bromochloroacetic-acid and Ameloblastoma

Ameloblastic carcinoma is a malignant odontogenic neoplasm that has been reported only rarely in veterinary species. A 16-y-old Arabian crossbred mare was presented for evaluation of a hard mass on the body of the mandible, with evidence of osteolysis on radiographs. Incisional biopsies revealed an invasive neoplasm comprised of spindloid epithelial cells with a high mitotic count and partial dual cytokeratin-vimentin immunoreactivity. The horse was euthanized because of rapid tumor progression 3 mo after presentation. Postmortem evaluation revealed partial obliteration of the mandible by a large, firm-to-hard, tan, locally destructive and invasive mass with no gross or histologic evidence of metastasis. Postmortem histology revealed a poorly differentiated epithelial neoplasm with variably prominent features suggestive of odontogenic histogenesis: a plexiform ribbon architecture, infrequent basilar palisading with antibasilar nuclei, rare basilar cytoplasmic clearing, subepithelial matrix hyalinization, and partial dual cytokeratin-vimentin immunoreactivity. Features of malignancy included regions of necrosis, pronounced cellular atypia, a high mitotic count, extensive tissue invasion and local tissue destruction, and extension of neoplastic cells beyond the margins of the mandibular bone. Collectively, these features are most consistent with mandibular ameloblastic carcinoma. Including our case described here, ameloblastic carcinoma has been reported in only 5 horses. The microscopic features reported most consistently are dual cytokeratin-vimentin immunoreactivity, a high mitotic count, and basilar palisading. Ameloblastic carcinoma should be considered as a differential diagnosis for rapidly growing, locally invasive masses arising from the dentate jaw of horses.

Topics: Ameloblastoma; Animals; Carcinoma; Female; Horse Diseases; Horses; Keratins; Mandibular Neoplasms; Odontogenic Tumors; Vimentin

The solid variant of odontogenic keratocyst (SOKC) is an extremely rare odontogenic lesion, which remains poorly defined even in the 2017 World Health Organization odontogenic tumour classification. It is difficult to distinguish between SOKC and so called keratoameloblastoma (KAB), both rare lesions that have similarities in clinical, histological and biological characteristics. Here, we report clinicopathological data and results of molecular analysis of nine cases with a literature review. First, they were compared to previously reported cases of SOKC and/or KAB, and many overlaps were found in clinical and pathological characteristics. Second, we performed PCR analysis for BRAF V600E mutation. Although ameloblastoma-like epithelia were often encountered, none exhibited BRAF V600E mutation, which has been reported to occur frequently in ameloblastomas but not in odontogenic keratocysts (OKCs). One of two cases of SOKC in the present series from which fresh frozen tissue specimens were available was found to harbour PTCH1 mutations, indicating that these were more likely to be a subtype of OKC. Moreover, we also examined the differences between SOKC and primary intraosseous carcinoma (PIOC) with regard to the expression of cytokeratins (pan-CK, CK5/6, CK7, CK8/18, CK10, CK14 and CK19), p53 and Ki-67. The proportions of p53-and Ki-67-positive cells were significantly higher in PIOC than in SOKC. These findings suggest that immunostaining for p53 and Ki-67 would be useful to differentiate between SOKC and PIOC. We also conducted a review of SOKC and KAB cases reported in the English language literature.

Topics: Adult; Aged; Ameloblastoma; Female; Humans; Keratins; Ki-67 Antigen; Male; Middle Aged; Odontogenic Cysts; Odontogenic Tumors; Retrospective Studies; Tumor Suppressor Protein p53; World Health Organization

This study was focused on the immunohistochemical profile of the adenomatoid odontogenic tumor. A Pub/Medline search revealed a number of immunohistochemical studies including cytokeratin profiles, extracellular matrix proteins, Integrins, ameloblast-associated proteins resorption regulators (RANK, RANKL), p53, PCNA, MDM2 protein, cyclin D1, Ki-67, Bcl-2 metallothionein, metalloproteinases, D56 hepatocyte growth factor, c-met, DNA methyltransferase, podoplanin, TGF-βI, Smad-2/3, Smad-I-5/-8, Smad 4, beta- catenin, calretinin, and clonality. Careful interpretation of the findings indicates that the adenomatoid odontogenic tumor may be more of a hamartomatous than neoplastic nature.

Topics: Ameloblastoma; DNA Modification Methylases; Extracellular Matrix Proteins; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Jaw Neoplasms; Keratins; Membrane Proteins; Metalloproteases; Metallothionein; Neoplasm Proteins; Nuclear Proteins

Keratoameloblastoma is a rare subtype of ameloblastoma. It tends to have a poor prognosis, and therefore a careful diagnosis based on imaging is important in planning appropriate surgical treatment for this distinctive type of ameloblastoma. A unique feature of keratoameloblastoma is atypical calcification inside the mass, such as a ground-glass appearance, internal calcification, or a mixed radiolucent and radiopaque pattern. Because of its poor prognosis and the likelihood of frequent recurrences, surgical resection is considered the treatment of choice. This study reports a new case of keratoameloblastoma with special emphasis on its radiologic features and reviews previously reported cases of keratoameloblastoma.

Topics: Ameloblastoma; Diagnosis, Differential; Humans; Keratins; Magnetic Resonance Imaging; Male; Maxillary Neoplasms; Middle Aged; Neoplasm Recurrence, Local; Radiography, Panoramic; Reoperation; Tomography, X-Ray Computed

Topics: Ameloblastoma; Carcinosarcoma; Chemotherapy, Adjuvant; Child; Diagnosis, Differential; Fatal Outcome; Female; Follow-Up Studies; Humans; Keratins; Mandibular Neoplasms; Neoadjuvant Therapy; Neoplasm Recurrence, Local; Radiotherapy, Adjuvant; Vimentin

To help the clinician understand the different odontogenic tumors found commonly in the maxillary sinus in terms of clinical and radiographic findings, diagnosis and treatment.. The classification of odontogenic tumors has changed recently with the addition of the odontogenic keratocyst and calcifying odontogenic cyst (Gorlin cyst) from the realm of odontogenic cysts to being classified by the WHO as odontogenic tumors based upon their neoplastic biologic behavior. The odontogenic keratocyst is now called a keratocystic odontogenic tumor. The calcifying odontogenic cyst is now called a calcifying cystic odontogenic tumor.. The diagnosis of odontogenic tumors of the maxillary sinus is difficult and challenging. Surgeons need to work in conjunction with an oral and maxillofacial pathologist to ensure accurate diagnosis for proper surgical planning.

Topics: Ameloblastoma; Calcinosis; Diagnosis, Differential; Fibroma; Humans; Keratins; Maxillary Sinus; Odontogenesis; Odontogenic Cysts; Paranasal Sinus Neoplasms; Tomography, X-Ray Computed

Keratoameloblastoma is an extremely rare variant of ameloblastoma, and a review of the English language literature yields only several documented cases of ketatoameloblastoma. This paper reports a keratoameloblastoma showing unique histological architecture. The patient was a 76-year-old Japanese man with a multilocular radiolucent lesion of the mandible extending from the left canine to the second molar area. Microscopically, the lesion was characterized by multicystic spaces lined by papillary projections of proliferating odontogenic epithelium with extensive surface parakeratinization in a lamellar accumulation of keratin. In addition, "hair-like" extensions of keratin were frequently found. There was no ghost cell type keratinization. Histological features of the odontogenic epithelium were similar to those of conventinal ameloblastoma. An additional prominent feature of the present ameloblastoma was formation of hard tissue in continuation, in part, of the accumulated keratin in the fibrous tissue. These hard tissues showed a woven bone- or cellular cementum-like appearance and were not in contact with odontogenic epithelium. The present case was finally diagnosed as "keratoa meloblastoma," although such a type of keratoameloblastoma has not been documented previously in the spectrum of ameloblastoma.

Topics: Aged; Ameloblastoma; Humans; Keratins; Male; Mandibular Neoplasms; Radiography

The keratoameloblastoma is a rare histologic variant of the ameloblastoma. Review of the English language literature revealed five case reports of keratoameloblastoma. We report the sixth case of this tumor. The tumor developed in the right posterior maxilla of a 26-year-old African-American man and demonstrated aggressive clinical behavior, analogous to conventional ameloblastoma. The initial biopsy specimen showed extensive cyst formation, which histologically resembled odontogenic keratocyst. However, the lining epithelium varied in thickness and there was separation and edema between the basal cells and the rest of the epithelium. The basal cells were strongly adherent to the underlying stroma unlike the basal layer of the odontogenic keratocyst, where cleavage often occurs in this area. Additionally, although the basal cells were palisaded and demonstrated nuclear polarization in areas, they were cuboidal rather than columnar. The excision specimen revealed more of a solid ameloblastic component in addition to the cystic component seen on the initial biopsy. Nevertheless, it is possible that the ameloblastoma had developed in an odontogenic keratocyst. Alternatively, it can be postulated that the keratoameloblastoma consists of both cystic and solid components, the former being analogous to the cysts of the conventional ameloblastoma.

Topics: Adult; Ameloblastoma; Ameloblasts; Biopsy; Cell Adhesion; Cell Nucleus; Collagen; Connective Tissue; Diagnosis, Differential; Epithelium; Humans; Keratins; Male; Maxillary Neoplasms; Odontogenic Cysts

In view of the still disputed relationship between adult adamantinoma and osteofibrous dysplasia in children, a unique case of adamantinoma, indicating a direct relationship between the two lesions, is presented with a review of the literature. The patient was a six-year-old boy who complained of pain and swelling in the left lower leg. Roentgenographs showed a loculate osteolysis surrounded by sclerosis within the cortex of the tibial shaft that would be typical of osteofibrous dysplasia. Although an osteofibrous-dysplastic component predominated histologically, some small islands of epithelial cells were scattered throughout the lesion. Immunohistochemically, the tumor cells of these epithelial islands gave a constant positive reaction for cytokeratin as well as vimentin, while the stromal cells in the osteofibrous dysplasia-like lesion were positive for vimentin only. This type of lesion is recorded in the Bone Tumor Registry of Westphalia at a rate of 8.3% for osteofibrous dysplasia, and of 25% for adamantinoma. A review of the literature, yielding reports with remarkable uniformity on 14 cases beyond the present one, suggests the existence of a separate clinicopathologic entity to be called juvenile intracortical adamantinoma with predominant osteofibrous dysplasia-like features, and which might be a regressing form of adamantinoma specific in childhood.

Topics: Ameloblastoma; Bone Neoplasms; Child; Fibrous Dysplasia of Bone; Humans; Immunohistochemistry; Keratins; Male; Tibia; Vimentin

The histologic classification for odontogenic carcinomas is still under revision; thus, the differentiation between the terms "malignant ameloblastoma" and "ameloblastic carcinoma" has not been definitely stated. Nevertheless, it is recommended to reserve the former for those lesions that, in spite of an apparently innocuous histology, have given origin to metastatic growths, and to apply the latter for those ameloblastomas in which there is histologic evidence of malignancy in the primary, recurrent or metastatic lesions. A case of an ameloblastic carcinoma in the mandible is presented. Histologically, it was characterized by areas with features of a typical ameloblastoma and areas with anaplastic appearances.

Topics: Ameloblastoma; Carcinoma; Cell Nucleolus; Cell Nucleus; Collagen; Cytoplasm; Humans; Keratins; Male; Mandibular Neoplasms; Middle Aged; Neoplasm Recurrence, Local

Topics: Adamantinoma; Adolescent; Adult; Ameloblastoma; Biomarkers, Tumor; Child; Female; Head and Neck Neoplasms; Humans; Immunohistochemistry; Keratins; Male; RNA-Binding Protein EWS; Sarcoma, Ewing; Young Adult

Adenomatoid odontogenic tumor (AOT) was classified by the World Health Organization as a mixed odontogenic tumor in 1992 and reclassified without a clear rationale as an epithelium-only tumor in 2005. The purpose of this study was to investigate if there was any evidence to suggest AOT might be a mixed odontogenic tumor.. Immunohistochemical studies with nestin, dentin sialophosphoprotein (DSPP), cytokeratin, and vimentin were performed using 21 cases of AOT, and the staining results were analyzed according to the various morphologic patterns seen in AOT. Sirius red stain was used to detect the presence of collagen types I and III in AOT products.. Our results showed that 20 of 21 (95.23%), 0 of 21 (0%), 21 of 21 (100%), and 20 of 21 (95.23%) cases expressed nestin, DSPP, cytokeratin, and vimentin, respectively. Some cells in rosette/duct-like structures (RDSs) expressed nestin, vimentin, or both, without cytokeratin. Coexpression of vimentin and cytokeratin or of nestin, cytokeratin, and vimentin was noted in some cells. Sirius red staining was positive in eosinophilic products in RDSs, double-layered spheres, and dentinoids.. Although most AOT cells appear epithelial, there is a small population of cells expressing mesenchymal proteins and secreting collagen types I and III. This evidence suggests that AOT is a mixed odontogenic tumor.

Topics: Ameloblastoma; Collagen; Humans; Keratins; Nestin; Odontogenic Tumors; Vimentin

The archetypal solitary fibrous tumor (SFT) features fibroblastic cells with varying cellularity without any particular architectural arrangement in a collagenous matrix, with staghorn vessels, CD34 and STAT6 expression, and NAB2::STAT6. To date, this fusion is thought to be specific for SFT. With more routine use of fusion gene panels, the histologic diversity of NAB2::STAT6-positive tumors is increasingly appreciated. Here we present four head and neck tumors harboring NAB2::STAT6 but exhibiting remarkably unusual morphologic features for SFT. All cases were pulled from the authors' consultation files. Immunohistochemistry was performed, along with targeted RNA sequencing in all cases, plus DNA next-generation sequencing on two. The cases arose in the nasal cavity (n = 2), retromolar trigone (n = 1) and parapharynx (n = 1), in patients ranging from 39 to 54 (mean, 44). Both nasal cases were biphasic, with a variably cellular collagenized stroma that resembled SFT but also interspersed malignant epithelial and neuroepithelial nests. One of the nasal cases also exhibited overt rhabdomyoblastic differentiation within both components. The two non-nasal cases were comprised of plump, epithelioid cells that were diffusely positive for pan-cytokeratin. One of these cases had prominent cystic change lined by overtly squamous epithelium. STAT6 immunostaining was positive in all cases, although the epithelial/neuroepithelial nests in the sinonasal cases were negative. All cases were confirmed to harbor NAB2::STAT6 by RNA sequencing. The two sinonasal cases were also found to harbor oncogenic mutations. The presented cases highlight a much broader histologic diversity than previously known for neoplasms with NAB2::STAT6. The biphasic nasal cases closely resemble teratocarcinosarcoma, while the epithelioid, cytokeratin-positive cases could be conceptualized as "adamantinoma-like," to borrow terminology already in use for Ewing sarcomas with complex epithelial differentiation. To identify similar cases, pathologists should have a low threshold for using STAT6 immunohistochemistry on any difficult-to-characterize head and neck tumor.

Topics: Adamantinoma; Ameloblastoma; Biomarkers, Tumor; Head and Neck Neoplasms; Humans; Keratins; Repressor Proteins; Solitary Fibrous Tumors; STAT6 Transcription Factor

Five cases of a heretofore unreported rare variant of thymic carcinoma characterized by a striking resemblance to adamantinoma of the mandible are described. The tumors occurred in 4 women and 1 man aged 58 to 76 years (mean: 67.8 y); they arose in the anterior mediastinum and measured from 5.3 to 12.0 cm in greatest diameter (mean: 8.9 cm). Presenting symptoms included chest pain, shortness of breath, and in 2 patients, pleural effusion. One tumor was asymptomatic and discovered incidentally. Histologically, the tumors were extensively desmoplastic, and the cellular proliferation was characterized by multiple islands of squamous epithelium with striking peripheral palisading of nuclei and central areas containing clear cells resembling a stellate reticulum. Areas of preexisting spindle cell thymoma were identified in 2 cases; these areas gradually merged with the higher-grade component of the lesion. Cystic changes were noted in 3 cases. Immunohistochemical studies in 3 cases showed the tumor cells were positive for cytokeratins, p40 and p63, and all showed a high proliferation rate (>50% nuclear positivity) with Ki-67. Next-generation sequencing was performed in 2 cases that showed amplification of the AKT1 gene (copy numbers 6 and 13). Clinical follow-up in 3 patients showed recurrence and metastasis after 1 and 2 years; 1 patient passed away 2 years after diagnosis due to the tumor. Desmoplastic adamantinoma-like thymic carcinoma represents an unusual histologic variant of thymic carcinoma that needs to be distinguished from metastases from similar tumors to the mediastinum.

Topics: Adamantinoma; Aged; Ameloblastoma; Biomarkers, Tumor; Epithelium; Female; Humans; Hyperplasia; Keratins; Male; Middle Aged; Thymoma; Thymus Neoplasms

Ameloblastoma is a locally aggressive odontogenic tumor. Etiopathogenesis and locally aggressive growth properties of ameloblastoma can be attributed to a hypoxic microenvironment conducive to tumor cell survival. Epithelial-derived follicular ameloblastoma cells (EP-AMCs) display enhanced basal autophagy, but the interplay of hypoxia and autophagy in EP-AMCs survival and ameloblastoma recurrence is unclear. We evaluated differential expression of autophagic markers in primary and recurrent ameloblastomas and hypothesized that hypoxia-induced autophagy supports EP-AMC survival. Primary and recurrent ameloblastomas were comparatively assessed for expression levels of pan-cytokeratin, Vimentin, and autophagic markers SQSTM1/p62, LC3, and pS6. EP-AMCs compared with human odontoma-derived cells (HODCs) were subjected to severe hypoxia to determine the interplay of hypoxia and autophagic process in posthypoxia survival. Pan-cytokeratin and SQSTM1/p62 were expressed by both primary and recurrent ameloblastoma epithelial cells while the ameloblastoma connective tissues displayed weak reactivity to vimentin. Under hypoxia, EP-AMC expression levels of hypoxia-inducible factor (HIF)-1α, p62, and LC3 were increased while pS6 was decreased posthypoxia. The combined decrease in pS6 and enhanced LC3 in EP-AMCs under hypoxia indicate that EP-AMCs re-establish basal autophagy under hypoxia. Taken together, these suggest a possible role of LC3-associated phagocytosis (LAP) in ameloblastoma cell survival.

Topics: Ameloblastoma; Autophagy; Cell Hypoxia; Cell Line, Tumor; Epithelial Cells; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Keratins; Sequestosome-1 Protein; Tumor Microenvironment; Vimentin

To investigate the clinical features, pathologic manifestations, and biologic behaviors of a variant of ameloblastoma with basal cell features (AM-BC).. Following retrospective review of the clinical and pathological data of six cases of AM-BC, we described their histological and immunohistochemical (IHC) features and discussed the biologic behaviors, prognoses, pathogenesis, and clinical relevance of AM-BC. Direct sequencing of polymerase chain reaction products was also performed in all cases.. The six cases of AM-BC involved four women and two men, aged 22-82 years. Four lesions occurred in the maxilla and two in the mandible. Histologically, the basal cells tended to be arranged as unequally sized follicles, strands, or cords of odontogenic epithelium in the connective tissue stroma. Little or no stellate reticulum was present in the central portion of the nest. Expression of CKs was consistent with other histological variants of ameloblastoma (AM), but AM-BC had significantly higher p53 and Ki-67 (p < 0.05) labeling indices than other histological variants of AM. Two patients had BRAF gene mutations.. Ameloblastoma with basal cell features is a very rare variant of AM. Our study showed the differences and relationships that exist between AM-BC and other variants of AM, which could enhance understanding of AM-BC.

Topics: Adult; Aged, 80 and over; Ameloblastoma; Female; Humans; Immunohistochemistry; Keratins; Ki-67 Antigen; Male; Mandibular Neoplasms; Maxillary Neoplasms; Middle Aged; Mutation; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras); Retrospective Studies; Smoothened Receptor; Tumor Suppressor Protein p53; Young Adult

Keratoameloblastoma is an extremely rare odontogenic tumor, as only 18 cases have been reported in the literature.. The authors report a case of keratoameloblastoma in a 32-year-old woman and review the literature concerning the clinical features, radiological appearance, histopathological findings and treatment options.. Keratoameloblastoma is a rare tumor observed more frequently in males (sex ratio: 3:1) characterized by extensive keratin production in odontogenic islets and fibrous stroma.

Topics: Adult; Ameloblastoma; Diagnosis, Differential; Female; Humans; Keratins; Mandibular Neoplasms; Plastic Surgery Procedures; Radiography, Panoramic; Treatment Outcome

To identify cutoff values of markers that correlate with the histopathologic diagnosis of ameloblastic carcinoma (AC) and/or the increased recurrence potential of ameloblastoma (AB).. Immunohistochemical expression (IHCE) of 9 selected markers were investigated in 18 non-recurrent ameloblastomas (NRABs), 6 recurrent ameloblastomas (RABs), and 5 ACs.. No significant difference in IHCE of K6, K8, K16, K17, K18, K19, maspin, or syndecan-1 was observed among study groups. α Smooth muscle actin (α-SMA)-positive area in central epithelial cells significantly differentiated between AB and AC (P = .017; t -test). Ki-67 score significantly differentiated between AB and AC (P < .005; t -test) and between AC and RAB (P = .015; ANOVA/post hoc).. Ki-67 score of 75 cells/HPF (ROC curve) is a potential indicator of AC. Clinical recurrence of AB may be predicted by α-SMA expression pattern. Syndecan-1 and α-SMA may indicate a higher aggressive potential of AB when expressed in the stroma.

Topics: Actins; Ameloblastoma; Biomarkers, Tumor; Carcinoma; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Ki-67 Antigen; Neoplasm Recurrence, Local; Prognosis; Serpins; Syndecan-1

To evaluate the effectiveness of decompression as the primary treatment of odontogenic cystic lesions of the jaw involving factors that affect relative shrinking speed and bone regeneration.. A total of 32 patients with odontogenic cystic lesions of the jaw underwent decompression with customized thermoplastic resin stents. Clinical examinations and pre- and postdecompression panoramic radiographs were analyzed.. The mean relative speed of shrinkage of radicular cysts (RCs; 3.37 cm(2)/month) was faster than those of keratocystic odontogenic tumors (KCOTs; 2.87 cm(2)/month) and unicystic ameloblastomas (UABs; 2.71 cm(2)/month). The relative shrinking size increased linearly in a time-dependent manner for KCOTs (r = 0.849, P < .001), RCs (r = 0.681, P = .319), and UABs (r = 0.146, P = .730); a similar relation was detected between the primary radiolucent area of cystic lesions before decompression and relative shrinking speed after decompression in KCOTs (r = 0.481, P = .032), RCs (r = 0.260, P = .673), and UABs (r = 0.370, P = .366), but patient age did not affect the relative speed of shrinkage (P > .05). Furthermore, the increase in bone density was more significant in RCs than in KCOTs (P = .026) and UABs (P = .012) after decompression.. Decompression was effective in reducing odontogenic cystic lesions of the jaw and increasing bone density. For aggressive lesions, secondary definitive surgery was necessary.

Topics: Adult; Ameloblastoma; Bone Density; Decompression, Surgical; Dentigerous Cyst; Female; Humans; Jaw Neoplasms; Keratins; Male; Odontogenic Cysts; Radicular Cyst; Stents

Diagnostic criteria that have been specified for unicystic ameloblastomas (UAs) are not always helpful to differentiate these cystic tumors from common odontogenic cysts. The aim of this study therefore was to identify additional histopathological features (other than the features considered for the diagnosis of UA at present) that would be helpful to differentiate UA from odontogenic cysts.. One hundred histopathologically confirmed unicystic ameloblastomas and 20 cases each of radicular, inflamed dentigerous and non-inflamed dentigerous cysts were selected. Histopathological features of the UAs that are not used as diagnostic criteria at present were identified.. Hyperplastic arcading epithelial proliferations with stellate-reticulum-like and vacuolated cells were always seen associated with inflammation in odontogenic cysts, while in UA plexiform-like areas were also seen without inflammation (P < 0.001). In addition, a spiky rete pattern was observed in non-inflamed UA while this pattern was observed only in inflamed odontogenic cysts. Furthermore, spiky retes together with subepithelial hyalinization were usually observed in UAs while only subepithelial hyalinization was observed in non-inflamed dentigerous cysts.. Combinations of histopathological features were identified to differentiate non-inflamed UA from common odontogenic cysts. However, presence of inflammatory changes in UA precludes the use of features identified in the present study for diagnostic purposes.

Topics: Ameloblastoma; Ameloblasts; Connective Tissue; Dentigerous Cyst; Diagnosis, Differential; Epithelial Cells; Epithelium; Female; Humans; Hyalin; Hyperplasia; Inflammation; Keratins; Male; Radicular Cyst; Vacuoles; Young Adult

The objective of this study was to evaluate the cytological content of ameloblastomas of the jaw. Nine cases of ameloblastoma were punctured, and the intralesional material was processed using the cell block technique. After centrifugation, the pellet obtained from the punctured material was fixed in formaldehyde and routinely processed to inclusion in paraffin. The obtained sections were stained with haematoxylin and eosin (H&E). Immunohistochemical reactions against anti-pan-cytokeratin (AE1/AE3) were performed to measure the presence of epithelial cells. Cytological analyses of the obtained slides revealed the presence of epithelial cells (as evidenced by AE1/AE3 labelling) and acellular amorphous eosinophilic materials. These cytological findings, in light of clinical and imaging data, can be helpful in the presumptive diagnosis of this disease entity by eliminating other possible diagnoses. Nonetheless further studies are needed in order to determine the nature of the acellular amorphous eosinophilic material and to ascertain the immunoprofile of epithelial cells.

Topics: Ameloblastoma; Biopsy, Fine-Needle; Cytodiagnosis; Epithelial Cells; Erythrocytes; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Odontogenic Tumors; Paraffin Embedding

A 3.5-year-old, male, neutered dwarf rabbit was presented with a history of a fast-growing gingival mass at the maxilla. The neoplasm was surgically completely excised. Histopathologically, an expansively growing, multilobulated, partially cystic, peripheral, keratinizing ameloblastoma was diagnosed. The immunohistochemical phenotyping of the tumour cells resulted in cytoplasmic labelling with various pan-cytokeratin antibodies. The cytokeratins 5/6, 7, 10 and 14 were expressed variably. Cytokeratin 20 was not detected. Vimentin was expressed in the cytoplasm of mesenchymal cells of the tumour stroma. In addition, in the nuclei of approximately 10% of the tumour cells the protein of the tumour suppressor gene p53 was expressed while in approximately 5% the proliferation marker Ki67 was expressed. Odontogenic tumours should be considered as a differential diagnosis of oral masses in rabbits.

Topics: Ameloblastoma; Animals; Immunohistochemistry; Keratins; Male; Maxillary Neoplasms; Rabbits

Oral squamous cell carcinoma (OSCC) and canine acanthomatous ameloblastoma (CAA) represent two epithelium-derived neoplasms that affect the oral cavity of dogs. The expression of cytokeratins (CKs) and calretinin has been previously established in the canine tooth bud and odontogenic tumours. The aim of this study was to characterize the CK and calretinin expression profile of OSCC in comparison to CAA and canine tooth bud tissues. Samples from 15 OSCC and 15 CAA cases, as well as 6 tooth buds and 2 normal gingival tissues were examined. OSCC CK expression was consistent with the CK expression profile of CAA and canine tooth bud tissue. Calretinin was positively expressed in 10 of 15 OSCC cases, with 5 cases demonstrating high staining intensity. Only 2 of 15 CAA cases demonstrated mild-moderate staining intensity. The statistically significant difference in staining pattern and intensity of calretinin in OSCC and CAA can help distinguish between these two tumour types.

Topics: Ameloblastoma; Animals; Antibodies, Monoclonal; Calbindin 2; California; Carcinoma, Squamous Cell; Dog Diseases; Dogs; Immunohistochemistry; Jaw Neoplasms; Keratins; Mouth Neoplasms; Tooth; Universities

The adenomatoid odontogenic tumor (AOT) is an uncommon tumor of odontogenic origin, composed of odontogenic epithelium and characterized by slow but progressive growth. We report a rare case of AOT in an 18-year-old, who presented with a palpable bony-hard swelling in the anterior maxillary region. The tumor was radiographically well-defined, and exhibited unilocular radiolucency. Histologically, the appearance was of solid nodules of cuboid or columnar cells of odontogenic epithelium, forming typical nests or duct-like structures. Immunohistochemistry was positive for cytokeratins (CK) CK5/6, CK17, CK19 and negative for KI-67. The results were consistent with a diagnosis of AOT.. A case of AOT is presented, emphasizing on the importance of recognizing neoplasms arising in odontogenic tissues. Recurrences seldom occur, and surgical cure is recommended.

Topics: Adolescent; Ameloblastoma; Female; Humans; Immunohistochemistry; Keratins; Ki-67 Antigen; Maxillary Neoplasms; Odontogenic Tumors; Radiography

Ameloblastoma is a benign odontogenic neoplasm with an origin reputed to reactivation of odontogenic structures. Histological classification is based on microscopic features and architectural distribution of neoplastic cells. The importance of squamous metaplasia and keratinization has been disputed in ameloblastomas. Clinical and histopathological aspects were evaluated of 85 ameloblastomas, with attention to keratinization and squamous metaplasia features.. Clinical-demographical information of 85 ameloblastomas were gleaned from the medical records. Microscopic analysis of all cases was carried out with emphasis on keratinization aspects of each tumor.. Most ameloblastomas (54.12%) were diagnosed in males with a mean age of 37 years. Fifty-six patients were Caucasians (65.88%) and the mandible was affected in 68 (89.4%) cases. Most cases analyzed presented areas of squamous metaplasia/keratinization. Recurrence was detected in 16 cases; this was not related to keratinization aspects of the tumor.. Keratinization is a common feature in ameloblastomas with no impact in tumor behavior.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Ameloblastoma; Child; Female; Humans; Jaw Neoplasms; Keratins; Male; Middle Aged; Young Adult

Calcifying cystic odontogenic tumors (CCOTs) are benign cystic lesions of odontogenic origin characterized by an ameloblastoma-like epithelium and the presence of a group of cells named ghost cells. The pattern of cytokeratin (Ck) expression on these lesions remains unclear and needs to be clarified. To this end, the expression of Ck6, Ck13, Ck14, Ck18, and Ck19 in the epithelium lining of 7 cases of CCOTs was evaluated by immunohistochemistry. For this, the epithelium lining was divided into 3 distinct regions: basal layer, suprabasal layer, and the compartment composed of ghost cells. In this study, 6 cases (85.7%) were classified as type 1 and 1 (14.3%) as type 4. All cases were negative for Ck13 and Ck18, despite the epithelial layer, as well as in the ghost cells. Ck6 was only positive in the ghost cells. Positivity for Ck14 and Ck19 was found in the basal and suprabasal layers, including the ghost cells. The results showing positivity for Ck14 and Ck19 in all of the analyzed cases reinforce CCOT as being of odontogenic origin, and the restricted expression of Ck6 in the ghost cells may be indicative that these cells suffer an altered differentiation into hair follicles in CCOTs.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Cell Differentiation; Epithelium; Female; Hair Follicle; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Male; Middle Aged; Odontogenic Cyst, Calcifying; Odontogenic Tumors; Young Adult

A 13-year-old castrated male Labrador retriever dog presented with a mass caudal to the first molar of his left mandible. Although the tumor was excised, a recurrent tumor was detected one month later and resected. Both tumors displayed invasive growth and were composed of neoplastic proliferation arranged in irregular lobules, nests and cords continuous with mucosal epithelium. The most prominent feature of the tumors was the presence of many proliferating spindle cells admixed with palisading basal-like cells, acanthocytes and stellate cells. In immunohistochemical examinations, the spindle cells were found to be positive for vimentin; cytokeratin AE1/AE3, 5/6, 14 and 19; and p63. The other neoplastic cells were positive for all of these markers shown above except vimentin. Based on these findings, the tumors were diagnosed as spindle cell ameloblastic carcinoma.

Topics: Ameloblastoma; Animals; Carcinoma; Dog Diseases; Dogs; Immunohistochemistry; Jaw Neoplasms; Keratins; Male; Neoplasm Recurrence, Local; Vimentin

Peripheral ameloblastoma (PA) is a rare extraosseous odontogenic tumor with histological characteristics similar to those of the common intraosseous ameloblastoma. Two questions regarding PA remain: its histogenic origin and how to differentiate between PA and intraoral basal cell carcinoma. We describe a patient with PA. The result of immunohistochemistry showed cytokeratin (CK) 7-, CK14+, CK19+, AE1/AE3+, CAM5.2-, 34 β E12+, epithelial membrane antigen-, Ber-EP4-, p53-, p63+, and low Ki-67, that was similar to those of 4 cases of intraosseous ameloblastoma. Our results suggest that a PA originates from odontogenic epithelial remnants, rather than from the oral epithelium.

Topics: Ameloblastoma; Antiporters; Biomarkers, Tumor; Carcinoma, Basal Cell; Diagnosis, Differential; Gingival Neoplasms; Humans; Immunohistochemistry; Keratins; Ki-67 Antigen; Male; Middle Aged; Molar; Mucin-1; Tumor Suppressor Protein p53

Peripheral ameloblastic carcinoma is an extremely rare odontogenic tumor derived from the remnants of dental lamina and/or mucosal epithelium of the oral mucosa. We present a case of secondary peripheral ameloblastic carcinoma of the mandibular gingiva. The patient was a 71-year-old man with gingival swelling and persistent bleeding. Exfoliative cytology revealed cohesive clusters composed of basaloid cells with nuclear atypia and various forms of keratinized cells of dysplastic squamous appearance. Some cell groups had a peripheral palisade. Histology of the biopsy and surgically removed specimens revealed characteristic features resembling squamous cell carcinoma, basal cell carcinoma, and benign follicles of ameloblastoma. These neoplastic structures, as well as proliferation and elongation of the mucosal epithelium, comprised an extensive network. The varied cytopathologic findings may be related to proliferation and transformation of basal cells of the mucosal epithelium toward ameloblastic carcinoma and variable squamous differentiation.

Topics: Aged; Ameloblastoma; Cell Shape; Gingival Neoplasms; Humans; Keratins; Male; Mandible

Odontogenic tumours are considered to be relatively rare; however, several histologically distinct types have been identified in dogs. The more common canine odontogenic tumours are peripheral odontogenic fibroma and canine acanthomatous ameloblastoma. The expression of cytokeratins (CKs) has been established for the human dental germ and odontogenic tumours. The aim of the present study was to describe the immunohistochemical expression of a panel of CKs in the epithelium of the canine dental germ, normal gingiva and odontogenic tumours arising in this species. Samples from 20 odontogenic tumours, 12 tooth germs and three normal gingival tissues were obtained. Each sample was stained with haematoxylin and eosin and subjected to immunohistochemistry for CK expression. The typical expression pattern of CKs in the odontogenic epithelium and gingiva of dogs was CK14 and CK5/6. CKs 7, 8, 18 and 20 were generally absent from the canine dental germ, gingiva and odontogenic tumours. Dogs and man therefore exhibit similar CK expression in the odontogenic epithelium.

Topics: Ameloblastoma; Animals; Cell Differentiation; Dog Diseases; Dogs; Epithelium; Fibroma; Gene Expression Regulation, Neoplastic; Gingiva; Gingival Neoplasms; Intermediate Filaments; Keratins; Neoplasm Proteins; Odontogenic Tumors; Odontoma; Tooth Germ

The expression of the HOX gene network in mid-stage human tooth development mostly concerns the epithelial tooth germ compartment and involves the C and D HOX loci. To further dissect the HOX gene implication with tooth epithelium differentiation we compared the expression of the whole HOX network in human ameloblastomas, as paradigm of epithelial odontogenic tumors, with tooth germs. We identified two ameloblastoma molecular types with respectively low and high number of active HOX C genes. The highly expressing HOX C gene ameloblastomas were characterized by a strong keratinized phenotype. Locus C HOX genes are located on chromosome 12q13-15 in physical contiguity with one of the two keratin gene clusters included in the human genome. The most posterior HOX C gene, HOX C13, is capable to interact with hair keratin genes located on the other keratin gene cluster in physical contiguity with the HOX B locus on chromosome 17q21-22. Inside the HOX C locus, a 2.2 kb ncRNA (HOTAIR) able to repress transcription, in cis, along the entire HOX C locus and, in trans, at the posterior region of the HOX D locus has recently been identified. Interestingly both loci are deregulated in ameloblastomas. Our finding support an important role of the HOX network in characterizing the epithelial tooth compartment. Furthermore, the physical contiguity between locus C HOX and keratin genes in normal tooth epithelium and their deregulation in the neoplastic counterparts suggest they may act on the same mechanism potentially involved with epithelial tumorigenesis.

Topics: Adult; Ameloblastoma; Female; Genes, Homeobox; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Male; Middle Aged; Real-Time Polymerase Chain Reaction

Global hypomethylation is a common epigenetic event in cancer. Keratocystic odontogenic tumor (KCOT) and ameloblastoma are different tumors but posses the same tissue in origin. Here, we investigated long interspersed nuclear element-1 (LINE-1 or L1) methylation status between ameloblastoma and KCOT.. We studied the methylation levels of the long interspersed nucleotide element-1 (LINE-1) in ameloblastoma and KCOT. After collecting ameloblastoma cells and epithelium lining cells of KCOT by laser capture microdissection from paraffin embedded tissue, combined bisulfite restriction analysis of LINE-1 (COBRALINE-1) was performed to measure LINE-1 methylation levels.. The LINE-1 methylation level in KCOT (53.16 +/- 12.03%) was higher than that in ameloblastoma (36.90 +/- 16.52%), with a statistical significance of P = 0.001. The ranges of LINE-1 methylation of both lesions were not associated with either age or sex.. We found LINE-1 hypomethylation levels between ameloblastoma and KCOT are different. Therefore, global methylations between these tumors are processed differently.

Topics: Adult; Aged; Aged, 80 and over; Ameloblastoma; Cell Transformation, Neoplastic; Child; DNA Methylation; DNA, Neoplasm; Female; Humans; Jaw Neoplasms; Keratins; Long Interspersed Nucleotide Elements; Male; Middle Aged; Odontogenic Tumors; Promoter Regions, Genetic; Restriction Mapping; Young Adult

Topics: Ameloblastoma; Biomarkers; Gingival Neoplasms; Humans; Immunophenotyping; Keratin-18; Keratin-7; Keratin-8; Keratins

To establish and characterize the cell line of ameloblastoma (AM) by transfection with human telomerase reverse transcriptase (hTERT).. Primary cultures of AM cells were infected with a retroviral vector encoding hTERT. Infected cells were selected and checked by immunocytochemistry (ICC), in vitro proliferation, reverse transcriptase polymerase chain reaction (RT-PCR), senescence associated beta galactosidase staining (SA-beta-Gal staining), telomerase activity assay.. Compared to the uninfected cells, which arrested at the population doublings (PDL) of 6, the infected cells were more active in proliferation and reached 65 PDL to date. ICC confirmed the epithelial origin of the infected cells based on positive pan-cytokeratin and negative vimentin expression. There was no senescent signal in infected cells but not in uninfected cells. hTERT mRNA and telomerase activity were detected stably in infected cells.. The infected AM cells were immortalized after transfection with hTERT and can serve as a genetically defined model for AM study.

Topics: Ameloblastoma; Cell Line, Transformed; Cell Line, Tumor; Cell Proliferation; Genetic Vectors; Humans; Jaw Neoplasms; Keratins; Retroviridae; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Telomerase; Transfection; Vimentin

To evaluate expression of BH3-only proteins in odontogenic tumors, expression of Bid, Bim, Bad, Noxa, and Puma was analyzed in ameloblastic tumors as well as in tooth germs.. Nine tooth germs, 37 ameloblastomas, and five malignant ameloblastic tumors were examined immunohistochemically with antibodies against Bid, Bim, Bad, Noxa, and Puma.. Immunohistochemical reactivity for Bid, Bim, Bad, Noxa, and Puma was detected in the cytoplasm of cellular components in normal and neoplastic odontogenic tissues. Expression of these BH3-only proteins was evident in odontogenic epithelial cells near the basement membrane in tooth germs and ameloblastic tumors. Acanthomatous ameloblastomas showed no reactivity for Bid, Bim, Bad, Noxa, or Puma in keratinizing cells, whereas granular cells in granular cell ameloblastomas reacted with these BH3-only proteins. Basal and desmoplastic ameloblastomas and ameloblastic carcinomas showed immunoreactivity for the BH3-only proteins in most neoplastic cells.. Expression of Bid, Bim, Bad, Noxa, and Puma in tooth germs and ameloblastic tumors suggests that the BH3-only proteins have a role in apoptotic cell death of normal and neoplastic odontogenic epithelium. Distinctive expression patterns of these BH3-only proteins in ameloblastoma variants suggest that the BH3-only proteins might be involved in tumor cell differentiation of ameloblastomas.

Topics: Ameloblastoma; Apoptosis Regulatory Proteins; Basement Membrane; Bcl-2-Like Protein 11; bcl-Associated Death Protein; BH3 Interacting Domain Death Agonist Protein; Cell Differentiation; Dental Enamel; Dental Sac; Endothelial Cells; Epithelial Cells; Fibroblasts; Humans; Immunohistochemistry; Keratins; Membrane Proteins; Mesoderm; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tooth Germ

Peripheral ameloblastoma (PA) is a rare variant of ameloblastoma occurring in the extraosseous region. With regard to the histogenesis of the tumor, two major sources of origin are considered: odontogenic epithelial remnants and the gingival epithelium. In this study, we examined the immunohistochemical profiles of cytokeratins (CKs) and Ki-67 labeling index (LI) of PAs, and discuss the histogenesis and the biologic behavior of the PA.. Eight cases of PA were retrieved from the pathology files of 212 cases of ameloblastoma that had been registered at our hospital. Immunohistochemical staining was performed in seven cases using monoclonal antibodies of six CKs (7, 8, 13, 14, 18, and 19) and Ki-67.. All cases of PA expressed CK13, 14, and 19. CK18 was positive staining in six cases, and CK8 in five cases. This staining pattern was similar to that in intraosseous ameloblastomas (IAs). The mean of Ki-67 LI of PAs (1.91%) was significantly lower than that of IAs (4.82%) (P = 0.002).. We consider that the PA originates from odontogenic epithelial remnants rather than from the gingival epithelium, and the Ki-67 LI of the tumor is a good prognostic indicator.

Topics: Adult; Aged; Ameloblastoma; Female; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Ki-67 Antigen; Male; Middle Aged

A 9-month-old male llama (Lama glama) was presented because of a rapidly growing mass on the right side of the face. Radiographs revealed a marked expansion of the right caudal face region with bone lysis involving the maxilla and the nasal, lacrimal, zygomatic, and palatine bones. Cytologically, the mass consisted of atypical round to polygonal cells with round nuclei and basophilic cytoplasms that formed acini and rows. Histologically, the mass consisted of anastomosing cords and sheets of neoplastic odontogenic epithelial cells embedded in a loose fibrovascular connective tissue. Single layers of peripheral, polarized, palisading, columnar epithelial cells were seen at the edges of some cords. Within the centers of the cords, epithelial cells showed rapid progression to keratin production. The histologic diagnosis was keratinizing ameloblastoma. Ameloblastomas are neoplasms of odontogenic epithelium that tend to be locally aggressive and can cause substantial destruction of bony structures. Because ameloblastomas do not tend to metastasize, they can be successfully treated by complete surgical excision, performed before extensive bony destruction occurs. Ameloblastoma, although expected to be rare, should be onthe list of differential diagnoses for facial swelling in llamas.

Topics: Ameloblastoma; Animals; Camelids, New World; Fatal Outcome; Jaw Neoplasms; Keratins; Male

Neoplasms and tumours related to the odontogenic apparatus may be composed only of epithelial tissue or epithelial tissue associated with odontogenic ectomesenchyme. The immunohistochemical detection of different cytokeratins (CKs) polypeptides and vimentin has made it easier to explain the histogenesis of many epithelial diseases. The present study aimed to describe the immunohistochemical expression of cytokeratins 7, 8, 10, 13, 14, 18, 19 and vimentin in the epithelial components of the dental germ and of five types of odontogenic tumours. The results were compared and histogenesis discussed. All cells of the dental germ were positive for CK14, except for the preameloblasts and secreting ameloblasts, in which CK14 was gradually replaced by CK19. CK7 was especially expressed in the cells of the Hertwig root sheath and the stellate reticulum. The dental lamina was the only structure to express CK13. The reduced epithelium of the enamel organ contained CK14 and occasionally CK13. Cells similar to the stellate reticulum, present in the ameloblastoma and in the ameloblastic fibroma, were positive for CK13, which indicates a nature other than that of the stellate reticulum of the normal dental germ. The expression of CK14 and the ultrastructural aspects of the adenomatoid odontogenic tumour probably indicated its origin in the reduced dental epithelium. Calcifying odontogenic epithelial tumour is thought to be composed of primordial cells due to the expression of vimentin. Odontomas exhibited an immunohistochemical profile similar to that of the dental germ. In conclusion, the typical IF of odontogenic epithelium was CK14, while CK8, 10 and 18 were absent. Cytokeratins 13 and 19 labelled squamous differentiation or epithelial cells near the surface epithelium, and CK7 had variable expression.

Topics: Ameloblastoma; Connective Tissue; Enamel Organ; Epithelial Cells; Humans; Immunohistochemistry; Intermediate Filaments; Keratin-10; Keratin-14; Keratin-7; Keratin-8; Keratins; Odontogenic Tumors; Odontoma; Tooth Germ; Vimentin

To establish an immortalized ameloblastoma cell line.. The primary cultured ameloblastoma cells were transfected with pRSV-Tag using Transfect AMINE kit. Tansfected cells were passaged to pass through crisis period and immortalize.. Cultured ameloblastoma cells were composed predominantly of closely packed small polygonal cells with epithelial morphology. They had limited life-span of 51 days in vitro. The small polygonal cells were eventually replaced by large flattened cells and subsequently became senescent and dead. On the other side, those tumor cells transfected with SV40Tag could live for a longer time. The majority of them died in crisis period while the survived cells from crisis period gained the ability to proliferate. There was no morphological change in TAM-1 compared with original cultured cells. A cell clone was harvested which was alive and keeping on proliferating after having been subcultured for 25 times. It was named TAM-1. The epithelial origin of TAM-1 was confirmed by strong immunoreactivity for cytokeratin in contrast to negative vimentin expression. It was detected that SV40Tag had been transfected into TAM-1 genesome and expressed continuously by PCR and RT-PCR.. TAM-1 is immortalized ameloblastoma cell line in vitro.

Topics: Ameloblastoma; Antigens, Polyomavirus Transforming; Cell Division; Cell Line, Transformed; Cell Survival; Female; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Plasmids; Time Factors; Transfection; Tumor Cells, Cultured; Vimentin

To investigate the proliferating activities and differentiation between peripheral cells and central cells in ameloblastoma.. Expressions of proliferating cell nuclear antigen (PCNA), Ki-67, CK10&13 and CK19 were detected in 43 ameloblastoma (15 follicular, 20 plexiform and 8 acanthomatous) by SP immunohistochemical methods.. The PCNA labelling indices were significantly higher in peripheral cells (5.12% +/- 2.76%) of tumour nests or strands than in central cells (1.36% +/- 1.02%, P < 0.001). The peripheral cells of tumour nests or strands exhibited a significantly higher Ki-67 labelling index (3.63% +/- 1.80%) than central cells (1.26% +/- 0.96%, P < 0.001). The labelling indices between PCNA and Ki-67 showed a significant correlation (P < 0.01). The positive expressions of CK10&13 and CK19 were significantly higher in central cells than in peripheral cells (P < 0.01).. The peripheral zones of tumour nests or strands are regarded as proliferating areas; there exists a significantly different differentiation between central cells and peripheral cells.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Cell Differentiation; Cell Division; Child; Female; Humans; Jaw Neoplasms; Keratins; Ki-67 Antigen; Male; Middle Aged; Proliferating Cell Nuclear Antigen

The purposes of this study were to investigate the distribution of cytokeratins in the different tissue types of ameloblastoma and to discuss the histogenesis of this tumor. CK19 and CK8, which are markers for odontogenic epithelium, reacted positively to the constituting cells in all types of ameloblastoma. This suggests that all types of ameloblastoma derive from odontogenic epithelium. However, the desmoplastic type diminished the odontogenic characteristics because the basal cells are negative to CK19. Immunoreactions of five kinds of cytokeratin revealed similar results in plexiform, follicular, acanthomatous, and granular cell types. The plexiform type is probably the original type of ameloblastoma; the other types have the characteristics of squamous epithelium, and the follicular, acanthomatous, and granular cell types can develop due to the differentiation of cells of the plexiform type into squamous epithelium.

Topics: Ameloblastoma; Epithelial Cells; Humans; Immunoenzyme Techniques; Jaw Neoplasms; Keratins; Molecular Weight

Topics: Aged; Aged, 80 and over; Ameloblastoma; Cell Nucleus; Cytoplasm; Diagnosis, Differential; Female; Follow-Up Studies; Humans; Keratins; Mandibular Neoplasms; Mucin-1; Neoplasm Recurrence, Local; Odontogenic Tumors

Apoptotic cell death in granular cell ameloblastomas was examined by immunohistochemistry using anti-single-stranded DNA (ssDNA) antibody and transmission electron microscopy. Routinely prepared sections of granular cell ameloblastomas showed various quantities of granular cells with some apoptotic nuclear fragments. Immunoreactivity for ssDNA was higher in granular cells than in other neoplastic cells. Ultrastructural examination revealed abundant lysosomes in the cytoplasm of granular cells. Numerous apoptotic cell fragments with condensed nuclei in granular cell clusters were phagocytosed by adjacent granular cells. On immunohistochemical characterization of cellular differentiation, granular cells were positive for cytokeratin, CD68, lysozyme and alpha-1-antichymotrypsin, but negative for vimentin, desmin, S-100 protein, neuron-specific enolase and CD15, indicating epithelial origin and lysosomal aggregation. These features suggest that the cytoplasmic granularity in granular cell ameloblastomas might be caused by increased apoptotic cell death of neoplastic cells and associated phagocytosis by neighboring neoplastic cells.

Topics: Adult; alpha 1-Antichymotrypsin; Ameloblastoma; Antibodies; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Apoptosis; Cell Differentiation; Cell Nucleus; Cytoplasm; Cytoplasmic Granules; Desmin; DNA, Single-Stranded; Female; Humans; Immunohistochemistry; Keratinocytes; Keratins; Lewis X Antigen; Lysosomes; Macrophages; Male; Microscopy, Electron; Middle Aged; Muramidase; Phagocytosis; Phosphopyruvate Hydratase; S100 Proteins; Vimentin

Epithelial odontogenic tumors exhibit considerable histological variation and are classified into several benign and malignant entities. Expression of amelogenin and cytokeratin 19 (CK19), that are potentially useful polypeptides for identification of odontogenic epithelial components, was evaluated in various types of epithelial odontogenic tumors.. Specimens of 33 ameloblastomas, three calcifying epithelial odontogenic tumors (CEOTs), two clear cell odontogenic tumors (CCOTs) and five malignant ameloblastomas were examined by immunohistochemistry using anti-amelogenin and anti-CK19 antibodies.. Immunohistochemical reactivity for amelogenin was detected in many peripheral columnar or cuboidal cells and some central polyhedral cells in ameloblastomas, and histological variants showed various degrees of amelogenin expression. Expression of CK19 was diffusely present in neoplastic cells in ameloblastomas, and decreased expression was found in keratinizing cells of acanthomatous variants and some neoplastic cells of desmoplastic variants. In CEOTs, immunohistochemical reactivity for amelogenin was detected in neoplastic cells and intercellular amyloid-like materials, whereas CK19 was expressed in neoplastic cells. CCOTs showed positive reactivity for amelogenin and CK19 in neoplastic cells. Malignant ameloblastomas exhibited various degrees of amelogenin expression with constant CK19 expression in neoplastic cells.. Diverse types of epithelial odontogenic tumors express amelogenin and CK19, suggesting that these tumors have ameloblastic differentiation or odontogenic epithelial properties.

Topics: Ameloblastoma; Amelogenin; Biomarkers, Tumor; Dental Enamel Proteins; Epithelial Cells; Humans; Immunohistochemistry; Keratins; Neoplasm Proteins; Odontogenic Tumors

A peripheral ameloblastoma with atypical features occurring on the left maxillary alveolar ridge of 40-year-old man is described, along with an immunohistochemical profile of its cytokeratin (CK). The lesion apparently originated from the surface gingival epithelium. The tumor nests or strands were highly cellular with a variable degree of squamous differentiation and microcyst formation. Occasional mitotic figures and dystrophic calcification, both of which are not seen in conventional ameloblastomas, were also observed. The tumor infiltrated deep into the alveolar mucosa, including the periodontal ligament, and showed histological and topographical evidence of atypism, resulting in resorption of the underlying alveolar bone. On the CK immunohistochemistry, CK19 was demonstrated in all the types of neoplastic epithelia, including microcyst-forming cells, densely packed round or spindle cells within the tumor nests, cells with squamous metaplasia, and peripheral tall columnar cells. The CK immunohistochemical findings suggest the lesion's cell of odontogenic origin; they may reflect an immature phenotypic expression of cell differentiation in the odontogenic epithelia during the tumor growth in the gingival mucosa.

Topics: Adult; Alveolar Bone Loss; Ameloblastoma; Calcinosis; Cell Differentiation; Epithelium; Gingival Neoplasms; Humans; Immunohistochemistry; Keratins; Male; Metaplasia; Mitosis; Mouth Mucosa; Periodontal Ligament; Phenotype

Craniopharyngiomas are generally considered to arise from the remnants of Rathke's pouch or a misplaced enamel organ. We tried to refine these hypotheses, comparing the subtypes of craniopharyngioma with Rathke's cleft cyst, a known Rathke's pouch derivative, and with ameloblastoma, an enamel organ derivative. Nineteen craniopharyngiomas (14 adamantinomatous and 5 papillary type tumors) and 17 ameloblastomas were immunostained for cytokeratin (CK) 7, CK 8, CK 14, and human hair keratin (HHK). All cases of adamantinomatous craniopharyngioma were CK 7+/CK 8+/CK 14+. Two cases (40%) of papillary craniopharyngioma were CK 7+/CK 8+/CK 14+, whereas the remaining three cases (60%) were CK 7+/CK 8-/CK 14+. Fifteen cases (88%) of ameloblastoma were CK 7-/CK 8+/CK 14+. Only the shadow cells present in adamantinomatous craniopharyngiomas were positive for HHK, which may indicate their follicular differentiation. In Rathke's cleft cyst, ciliated cuboidal cells were CK 7+/CK 8+/CK 14- and metaplastic squamous cells were CK 7+/CK 8/CK 14+. These findings suggest that both subtypes of craniopharyngioma may differ from ameloblastoma in histogenesis, although cytokeratin expression patterns may change during tumor development. Adamantinomatous craniopharyngioma may be related to a heterotopic ectodermal tissue which can differentiate into hair follicles, while papillary craniopharyngioma may arise from Rathke's cleft cyst.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Ameloblastoma; Biomarkers, Tumor; Craniopharyngioma; Female; Humans; Immunoenzyme Techniques; Jaw Neoplasms; Keratins; Male; Middle Aged; Neoplasm Proteins; Pituitary Neoplasms; Retrospective Studies

This study attempted to identify differential cytokeratin expression in cystic jaw lesions using immunohistochemical staining.. The charts from selected patients treated between 1983 and 1994 for jaw cysts were evaluated. Twenty-four paraffinized specimens were selected randomly for investigation with 5 immunohistochemical stains. The 4 diagnostic categories included ameloblastoma, dentigerous cyst, odontogenic keratocyst (OKC), and recurrent odontogenic keratocyst in patients with nevoid basal cell carcinoma (NBCC) syndrome. The 5 immunohistochemical stains included antibodies to cytokeratins 13, 17, and 18; CAM 5.2; AE 1/3; and carcinoembryonic antigen (CEA).. Differential staining of OKCs from patients with and without NBCC syndrome was found only with the antibody to cytokeratin 17. Furthermore, staining of OKCs in syndromic patients appeared to be stronger and more uniform than in nonsyndromic patients.. These findings suggest that immunohistochemical staining for cytokeratin 17 may aid in the diagnosis of OKCs and may be used to further subdivide these lesions based on the presence or absence of NBCC syndrome.

Topics: Ameloblastoma; Antibodies, Monoclonal; Basal Cell Nevus Syndrome; Dentigerous Cyst; Diagnosis, Differential; Humans; Immunoenzyme Techniques; Jaw Neoplasms; Keratins; Odontogenic Cysts; Random Allocation; Sampling Studies; Staining and Labeling

The botryoid odontogenic cyst (BOC) is considered a rare multilocular variant of the lateral periodontal cyst. The origin of the BOC can be seen in aberrant odontogenic tissue. The BOC is found especially in the premolar region of the mandible, as well as in the frontal region of the maxilla of patients aged between 60 and 70 years. Most of the 11 published articles of BOC have shown high rates of recurrence. Histopathologically the BOC is marked by multilocular cysts lined by a thin, nonkeratinized epithelium. Clusters of glycogen-rich epithelial cells may be noted in nodular thickenings of the cyst lining. For the clinician, the differentiation of the BOC from the keratocyst and ameloblastoma is relevant. One case of a large BOC (65-year-old male, BOC regio 33-45, diameter 5 cm, radiographically and histologically multilocular) is presented with a review of the literature, including the therapeutic management, and the possible diagnostic criteria are discussed. The immunohistochemically determined expression of cytokeratin (CK) 13 implicates the histogenetic origin of the BOC from the squamous epithelium of the oral cavity and excludes the origin from the small salivary glands. The expression of CK 19 and the lack of expression of p53, as well as the higher proliferation rate of the basal epithelial cell layer by the BOC, may be useful for distinction between the keratocyst.

Topics: Ameloblastoma; Biomarkers, Tumor; Diagnosis, Differential; Humans; Keratins; Male; Mandibular Diseases; Mandibular Neoplasms; Middle Aged; Nonodontogenic Cysts; Odontogenic Cysts

Comparative investigations of odontogenic cells in normally forming teeth and tumors may provide insights into the mechanisms of the differentiation process. The present study is devoted to late phenotypic markers of ameloblast and odontoblast cells, i.e., proteins involved in biomineralization. The in situ expression of amelogenins, keratins, collagens type III and IV, vimentin, fibronectin, osteonectin, and osteocalcin was performed on normal and tumor odontogenic human cells. The pattern of protein expression showed some similarities between ameloblasts and odontoblasts present in normally developing human teeth and cells present in neoplastic tissues of ameloblastic fibroma, ameloblastic fibro-odontomas, and complex odontomas. Amelogenins (for ameloblasts) and osteocalcin (for odontoblasts) were detected in cells with well-organized enamel and dentin, respectively. In contrast, "mixed" cells located in epithelial zones of mixed odontogenic tumors co-expressed amelogenins and osteocalcin, as shown by immunostaining. The presence of osteocalcin transcripts was also demonstrated by in situ hybridization in these cells. Keratins and vimentin were detected in the same epithelial zones. Tumor epithelial cells were associated with various amounts of polymorphic matrix (amelogenin- and osteocalcin-immunoreactive), depending on the types of mixed tumors. No osteocalcin labeling was found in epithelial tumors. This study confirms that the differentiation of normal and tumor odontogenic cells is accompanied by the expression of some common molecules. Furthermore, the gene products present in normal mesenchymal cells were also shown in odontogenic tumor epithelium. These data may be related to a tumor-specific overexpression of the corresponding genes transcribed at an undetectable level during normal development and/or to an epithelial-mesenchymal transition proposed to occur during normal root formation. A plausible explanation for the results is that the odontogenic tumor epithelial cells are recapitulating genetic programs expressed during normal odontogenesis, but the tumor cells demonstrate abnormal expression patterns for these genes.

Topics: Ameloblastoma; Amelogenin; Cell Differentiation; Cell Polarity; Cell Transformation, Neoplastic; Dental Enamel Proteins; Epithelial Cells; Extracellular Matrix Proteins; Gene Expression Regulation, Developmental; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; In Situ Hybridization; Infant, Newborn; Keratins; Odontogenesis; Odontogenic Tumors; Odontoma; Osteocalcin; Osteonectin; Tumor Cells, Cultured; Vimentin

Ameloblastomas appear to exhibit biological heterogeneity and, except in the case of malignancy, histological appearances that do not always allow their behaviour to be predicted. The aim of this study was to assess keratin expression in African ameloblastomas and to correlate this with their clinical and histological features.. Expression of simple keratins 7, 8, 18 and 19; cornification keratins 1 and 10; basal and differentiation keratins 5 and 14 and hyperproliferation-related keratins 6 and 16 in 14-39 cases of ameloblastoma was assessed by immunohistochemical methods.. There was patchy expression of keratin 7 in the suprabasal and stellate reticulum-like cells in some cases. All cases showed similar weak expression for keratins 8 and 18 in suprabasal and stellate reticulum-like cells but none showed keratin 1 or 10 expression. There was intense expression of keratins 5, 14 and 19 by all tumour cells suggesting that they may retain basal cell characteristics with a potential for proliferation. No consistent relationship was seen between histological types and keratin expression pattern. However, keratins 6 and 16, expressed by suprabasal and stellate reticulum-like cells, showed a marked variation within and between cases, with the highest levels of expression in squamous strands.. We propose that squamous strands may represent the sites of most active growth within individual tumours and expression of keratins 6, 16 and 19 may be predictors of rapid growth. There is a need for further investigation of this in longitudinal clinical studies.

Topics: Adolescent; Adult; Ameloblastoma; Antibodies, Monoclonal; Chi-Square Distribution; Child; Female; Humans; Immunoenzyme Techniques; Jaw Neoplasms; Keratins; Male; Middle Aged; Neoplasm Proteins; Prognosis; Statistics, Nonparametric

The monoclonal antibody NCL-CK13 was studied in specimens of craniopharyngioma, ameloblastoma and calcifying odontogenic cyst neoplasms and the mandible and maxillae of normal human fetuses. There was a decrease in NCL-CK13 as the dental lamina developed, with a complete loss in the enamel organ. The neoplastic epithelia of the neoplasms revealed a clear phenotypic and immunohistochemical reactive relationship to the stratified embroyonic mucosa, away from the enamel organ. This suggests that these neoplasms might have their histogenesis from early stage epithelium, the oral part of the dental lamina or its remnants.

Topics: Ameloblastoma; Amelogenesis; Case-Control Studies; Craniopharyngioma; Dental Enamel; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Jaw Neoplasms; Keratins; Odontogenesis; Odontogenic Cyst, Calcifying; Phenotype; Pituitary Neoplasms

In this report, the cytological features and differential diagnosis of the metastasis from and subsequent local recurrence of an unusual case of malignant (metastatic) ameloblastoma are described, with histological confirmation. Characteristic cytological findings included fibrovascular central cores surrounded by palisading crowded basaloid or columnar cells or both and rosette-like structures of tumor cells with central fibrillary material. Keratin debris in the background and cystic cavities were prominent components of the metastatic ameloblastoma. The basaloid cells showed scant-to-absent cytoplasm, round-to-oval to tear-shaped nuclei, rare longitudinal nuclear grooves, single or multiple nucleoli, and smooth-to-clefted nuclear contours. No features to predict malignant behavior were identified (abundant mitotic activity, necrosis, nuclear pleomorphism). The cytological features of ameloblastoma appear to be characteristic enough to allow definitive diagnosis. However, since the cytology of this tumor is underreported in the literature, the unwary observer could easily misdiagnose it, especially at metastatic sites.

Topics: Ameloblastoma; Biopsy, Needle; Diagnosis, Differential; Female; Humans; Keratins; Lung Neoplasms; Mandibular Neoplasms; Middle Aged; Neoplasm Recurrence, Local

Ameloblastomas are slowly growing, locally invasive neoplasms with a potentially destructive behaviour. The molecular mechanisms that regulate the cell growth and invasion of ameloblastoma cells are unknown. Because ameloblastoma cells placed in culture have a very limited lifespan, the establishment of immortalized clones of ameloblastoma cells would aid its study. We produced an immortalized ameloblastoma cell line (AM-1) using human papillomavirus type-16. This cell line maintains epithelial cell morphology and expresses cytokeratins K8, K14, K18, K19. Furthermore, bcl-2 protein, which prevents apoptosis, is expressed. We investigated the behaviour of these cells on a collagen matrix in vitro. These cells grew in a monolayer over foci of collagen degradation and could invade the collagen gel at such sites. Since the behavior of cell line AM-1 mimics the behavior of ameloblastoma in vivo, it may be a valuable model for the study of these neoplasms.

Topics: Ameloblastoma; Apoptosis; Cell Division; Clone Cells; Collagen; Culture Media; Epithelial Cells; Humans; Keratins; Neoplasm Invasiveness; Papillomaviridae; Proto-Oncogene Proteins c-bcl-2; Transfection; Tumor Cells, Cultured

The objective of this investigation was to study the relationship of the ghost cell ameloblastoma (GCA), which is a form of type II calcifying odontogenic cyst (COC), to the adamantinomatous craniopharyngioma (ACP). H&E sections of 26 examples of ACP were compared to three cases of GCA and to the reported microscopic features of that tumor. Clinical records of the ACPs were studied to determine their biologic behavior compared to that of the ameloblastomas. Immunohistochemical studies of nine examples of ACP were performed for KL1 (high mol.wt cytokeratins), 5D3 (low mol.wt cytokeratins) and involucrin (characteristic of terminally differentiated keratinocytes) using the peroxidase-antiperoxidase method. The results were compared with those reported for COC and ameloblastoma. ACP and GCA exhibited similar microscopic features, including pre-ameloblasts, tissue resembling stellate reticulum, ghost cells and calcifications; both tumors grew slowly and were invasive. ACP and COC, and by interpolation GCA, exhibited similar features with all three antibodies. The ghost cells did not exhibit any immunoreactivity but the adjacent cells stained positively for involucrin. The immunological features of ACP were similar to those reported in ameloblastomas for squamous differentiation. However, because of their rarity, no ameloblastomas exhibiting keratinization, including ghost cells, have yet been studied with these antibodies. We conclude that ACP and GCA are homologous lesions.

Topics: Ameloblastoma; Ameloblasts; Biology; Calcinosis; Cell Differentiation; Coloring Agents; Craniopharyngioma; Eosine Yellowish-(YS); Epithelial Cells; Fluorescent Dyes; Hematoxylin; Humans; Immunoenzyme Techniques; Immunohistochemistry; Jaw Neoplasms; Keratinocytes; Keratins; Molecular Weight; Odontogenic Cyst, Calcifying; Pituitary Neoplasms; Protein Precursors

Two cases of either peripheral odontogenic fibroma (POF) (WHO type) or peripheral ameloblastoma are reported. Their immunohistochemical characteristics were investigated in an attempt to clarify their histogenesis. The results showed that the epithelial component of this neoplasm tended to retain its distinct odontogenic character and expressed a keratin profile different from that of the overlying oral epithelium from which both cases most probably originated. The connective tissue element of these tumors was vimentin-positive and S-100 protein negative, confirming their mesodermal nature but precluding the possibility of ectomesenchymal derivation. No reactivity for desmin was noted.

Topics: Adult; Ameloblastoma; Desmin; Diagnosis, Differential; Female; Gingival Neoplasms; Humans; Immunohistochemistry; Keratins; Male; Maxilla; Odontogenic Tumors; Palatal Neoplasms; S100 Proteins; Vimentin

This report describes the cytologic, histologic, and clinical features of an ameloblastic carcinoma of the maxilla occurring in an 83-yr-old white male. A fine-needle aspiration revealed malignant cells with a predominantly small cell type morphology. There were also a few cells of a second type which were more polygonal to spindled with oval to elongate nuclei. A focal amorphous blue-grey matrix was noted in association with these cells. Although the biopsy showed prominent areas of squamous metaplasia, no squamous cells were seen in the cytologic sample.

Topics: Aged; Aged, 80 and over; Ameloblastoma; Biomarkers; Biomarkers, Tumor; Biopsy, Needle; Humans; Immunoenzyme Techniques; Keratins; Male; Maxillary Neoplasms; Tomography, X-Ray Computed

Expression of human leukocyte elastase inhibitor, elafin, otherwise known as skin-derived antileukoproteinase inhibitor (SKALP), was investigated in normal and abnormal oral tissues using a specific anti-SKALP rabbit antiserum. Weak staining was observed in keratinizing epithelia of normal oral mucosa but not in non-keratinizing mucosa. Increased expression was also observed in the suprabasal layers of dysplastic oral epithelia and in well-differentiated squamous cell carcinoma, but not in basal cell carcinoma. A uniform strong expression was observed in all supra-basal layers of odontogenic keratocyst epithelia, except in regions where inflammatory infiltrate was adjacent to keratocyst epithelia. In contrast, elafin expression in a small number of dentigerous cysts and ameloblastomas was more patchy. The increased levels of elafin in keratocyst epithelia and dysplastic tissue may be a cellular homoeostatic response to generate a protective barrier preventing proteolytic degradation of underlying elastic tissue.

Topics: Ameloblastoma; Animals; Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Dental Sac; Dentigerous Cyst; Elastic Tissue; Epithelium; Gene Expression Regulation; Gene Expression Regulation, Neoplastic; Gingiva; Homeostasis; Humans; Keratins; Mouth Mucosa; Mouth Neoplasms; Odontogenic Cysts; Peptide Hydrolases; Proteinase Inhibitory Proteins, Secretory; Proteins; Rabbits; Serine Proteinase Inhibitors

To obtain monoclonal antibodies reactive with odontogenic but not other types of epithelium, mice were immunized with homogenates of fixed ameloblastoma tissues, and monoclonal antibodies Y4 and M11 were produced. Y4 reacted immunohistochemically with odontogenic epithelial components but not with those of squamous differentiation, while M11 reacted with odontogenic epithelial components and a part of keratotic epithelial tissues. Immunoglobulin isotypes of both antibodies were IgM as determined by Ouchterlony immunodiffusion and enzyme-linked immunosorbent assays. Western blotting revealed that the antigen recognized by Y4 had a molecular mass of approximately 66 kDa; however, the antigen reactive with M11 was not identified by Western blotting in spite of various attempts in changing reaction conditions. These antibodies may be beneficial to histological analyses of odontogenic tissues and their related lesions.

Topics: Ameloblastoma; Animals; Antibodies, Monoclonal; Antigens, Neoplasm; Blotting, Western; Enzyme-Linked Immunosorbent Assay; Epithelium; Epitopes; Fixatives; Formaldehyde; Humans; Immunodiffusion; Immunoglobulin Isotypes; Immunoglobulin M; Immunohistochemistry; Keratins; Mice; Mice, Inbred BALB C; Mice, Inbred Strains; Molecular Weight; Odontogenesis; Paraffin Embedding; Tissue Fixation

A rare case of ameloblastoma with prominent stromal ossification in an 8-year-old female dog was studied. A bony mass recurred rapidly in the right mandible at the first molar region. Histopathologic examination revealed the lesion to be an atypical variant of ameloblastoma. Epithelial cells showed marked cell atypia, and mitotic figures were rather common. The collagenous stroma was abundant, with prominent formation of bone trabecular rimmed by active osteoblasts. The tumor was highly proliferative and aggressive, and thought to be malignant in nature.

Topics: Ameloblastoma; Animals; Cell Division; Dog Diseases; Dogs; Epithelium; Female; Immunohistochemistry; Keratins; Mandible; Mandibular Neoplasms; Ossification, Heterotopic; Osteoblasts

Topics: Ameloblastoma; Animals; Carcinoembryonic Antigen; Female; Glial Fibrillary Acidic Protein; Immunohistochemistry; Jaw; Jaw Neoplasms; Keratins; Macaca; Microscopy, Electron; Monkey Diseases

Five cases of odontogenic mixed tumour comprising of an ameloblastic fibroma, an adenomatoid odontogenic tumour, an odonto-ameloblastoma and two ameloblastic fibro-odontomas were immunohistochemically investigated. Odontogenic epithelial cells were fully positive for cytokeratin detected by antibody KL-1, although there were some differences in its intensity. In contrast, for tenascin, only immature dental papilla-like mesenchymal tissue, especially around the dental lamina-like odontogenic epithelium, was positive, while the myxomatous area and connective tissue were negative. Positive vimentin staining was observed in some areas of immature dental papilla-like cells as well as the basement membrane of odontogenic epithelium in the ameloblastic fibroma, suggesting that this tumour had developed at the early stage of tooth formation. Proliferating nuclear cell antigen-positive cells were generally rarely seen, but were frequently observed in epithelial cells of the ameloblastic fibroma and odonto-ameloblastoma. These observations suggest that tumour cells in each odontogenic mixed tumour possess characteristic proteins associated with proliferation potential and that ameloblastic fibroma and odonto-ameloblastoma have higher proliferation potential among the tumours examined.

Topics: Adolescent; Adult; Ameloblastoma; Cell Adhesion Molecules, Neuronal; Cell Division; Child; Child, Preschool; Extracellular Matrix Proteins; Female; Humans; Keratins; Male; Neoplasm Proteins; Odontoma; Proliferating Cell Nuclear Antigen; Radiography; S100 Proteins; Tenascin; Vimentin

Topics: Ameloblastoma; Humans; Keratins; Odontogenic Cysts

Twenty-four cases of adamantinoma and 24 cases of osteofibrous dysplasia of the long bones were studied to evaluate the expression and distribution of cytokeratin (CK) subtypes in relation to histogenesis and differentiation. The immunohistochemical study was performed on tissue fixed in buffered formalin and embedded in paraffin wax utilizing antibodies to vimentin, factor VIII, epithelial membrane antigen and cytokeratins of different molecular weights. In all cases the vimentin antibody marked positively in stroma, endothelium and osteoblasts, while factor VIII expression was confined to endothelial cells. In 71% of adamantinomas, vimentin showed strong immunoreactivity in the tumour cells of nests and tubules. CKAE1/AE3 and CK19 were strongly expressed in all morphological patterns of adamantinoma emphasizing their epithelial origin, while the antibodies to CK8 and CK18 showed a high percentage of negative responses. In osteofibrous dysplasia the epithelial-like component was much smaller than in adamantinoma and was present in scattered islands composed of a few cell positive for CKAE1/AE3 and CK19 and negative for other keratins. These results suggest that these two lesions are of a similar histogenesis.

Topics: Ameloblastoma; Antibodies, Monoclonal; Bone Neoplasms; Female; Fibrous Dysplasia of Bone; Fibula; Humans; Immunohistochemistry; Keratins; Male; Tibia; Vimentin

An unusual case of ameloblastoma which depicts cystic follicles containing orthokeratin, parakeratin, desquamated epithelium and necrotic material with dystrophic calcification is presented. The presence of ameloblast-like cells confirms the diagnosis of an ameloblastoma. However, certain features resembled those of the keratoameloblastoma and others, less convincively, the papilliferous keratoameloblastoma. The extensive keratinisation in this tumour and in the aforementioned neoplasms raises the question whether they represent variants of the acanthomatous ameloblastoma.

Topics: Adult; Ameloblastoma; Ameloblasts; Calcinosis; Cysts; Epithelium; Female; Humans; Keratins; Mandibular Neoplasms; Necrosis

Canalicular adenoma is a newly recognized salivary gland adenoma that may be confused with malignant salivary gland tumors. To better characterize this neoplasm, six examples were investigated with a panel of immunohistochemistry antibodies including anti-keratin (AE1/AE3), anti-epithelial membrane antigen, anti-carcinoembryonic antigen, anti-vimentin, anti-S-100, anti-muscle specific actin, and anti-glial fibrillary acid protein. All canalicular adenomas stained in a similar fashion showing positive staining with anti-keratin, anti-vimentin, and anti-S-100 (6 of 6 cases each). Rare focal staining with anti-epithelial membrane antigen and anti-glial fibrillary acid protein was noted (1 of 6 cases each). This immunohistochemistry staining pattern was compared with those of ameloblastoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma. Immunohistochemistry may be useful in the distinction of canalicular adenoma from other salivary gland tumors.

Topics: Actins; Aged; Ameloblastoma; Antibodies, Monoclonal; Carcinoembryonic Antigen; Carcinoma, Adenoid Cystic; Carcinoma, Ductal, Breast; Carcinoma, Lobular; Diagnosis, Differential; Female; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Keratins; Lip Neoplasms; Male; Membrane Glycoproteins; Middle Aged; Mouth Mucosa; Mucin-1; Mucins; Neoplasm Proteins; S100 Proteins; Salivary Gland Neoplasms; Salivary Glands, Minor; Vimentin

This paper describes the microscopical features of one variant of canine ameloblastoma. It is composed of islands and strands of odontogenic epithelium that have infiltrated through the surrounding stroma. Most of the basal cells are hyperchromatic, cuboidal and perpendicular to the basement membrane (palisading); in some areas their nuclei are located at the distal ends of the cells (reverse polarization) and their cytoplasm is vacuolated. These are the classical characteristics of the basal cell layer of ameloblastomas. The central cells of these tumours are closely-packed, spindle-shaped and exhibit cellular keratinization and calcification as prominent features. Amyloid is present between the neoplastic epithelial cells in some examples.

Topics: Ameloblastoma; Animals; Dog Diseases; Dogs; Female; Jaw Neoplasms; Keratins

Whether the peripheral ameloblastoma (PA) and intraoral basal cell carcinoma (BCC) are two different clinical entities or essentially the same lesion still remains unresolved. The immunophenotypes of neoplastic cells of peripheral and intraosseous ameloblastomas, ameloblastic carcinomas, and BCCs were studied using a panel of monoclonal/polyclonal antibodies and lectins. The major cytokeratins (CKs) of neoplastic cells of ameloblastomas were CKs 5 and 14, whereas co-expression of CKs 8, 18, and 19 was observed in the cells of the stellate reticulum-like areas. Metaplastic squamous and keratinizing cells found in follicular and acanthomatous variants of ameloblastomas expressed CKs 1 and 10, involucrin, and binding sites for the lectins Ulex europeaus agglutinin I and Helix pomatia agglutinin. beta 2-Microglobulin was uniformly negative in all cases of ameloblastomas and ameloblastic carcinomas studied. Cutaneous BCCs also demonstrated similar reactive patterns with the above-mentioned antigens. The most striking feature is the presence of a peritumorous band-like peanut agglutinin staining found in both BCCs and PAs but not in intraosseous ameloblastomas. This unique peanut agglutinin staining pattern of PA may be diagnostically useful for its histopathologic distinction from an intraosseous ameloblastoma that has infiltrated the soft tissue. The neoplastic cells of ameloblastomas express markers of less-differentiated epithelial cells. Despite differences in epithelial origins, PAs are tumors analogous to cutaneous BCCs.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Antigens, Differentiation; beta 2-Microglobulin; Bone Neoplasms; Carcinoma, Basal Cell; Female; Humans; Immunoenzyme Techniques; Keratins; Lectins; Male; Middle Aged; Protein Precursors; Receptors, Mitogen; Skin Neoplasms; Soft Tissue Neoplasms

Four cases of either combined occurrence of ameloblastoma and odontogenic keratocyst or a rare keratinising variant of ameloblastoma are presented. The cardinal histomorphologic characteristics are simultaneous occurrence of ameloblastomatous epithelial islands with central keratinisation and multiple keratinising cysts. Immunohistochemically the tumour elements were keratin positive and occasionally S-100 protein and desmin positive. Major differential diagnosis of these neoplasms are discussed.

Topics: Adult; Ameloblastoma; Connective Tissue; Desmin; Epithelium; Female; Humans; Keratins; Keratosis; Male; Mandibular Diseases; Mandibular Neoplasms; Maxillary Diseases; Maxillary Neoplasms; Odontogenic Cysts; S100 Proteins

Two solid and two cystic forms of calcifying odontogenic cysts were stained immunohistochemically to study keratin, carcinoembryonic antigen, epithelial membrane antigen, and S-100 protein expression in ghost cells. The patterns of immunoreactivity were compared with those of dentigerous cysts, odontogenic keratocysts, ameloblastomas, calcifying epitheliomas of Malherbe, and control samples. Immunostaining patterns of calcifying odontogenic cysts were found to be similar to the odontogenic lesions and different from calcifying epithelioma. It is concluded that ghost cells are "keratinizing" odontogenic cells showing aberrant differentiation. These cells should not be regarded as metaplastic. The similarity of the immunostaining patterns of cystic and solid calcifying odontogenic cysts supports the view that these lesions are two morphologic variants of the same entity.

Topics: Ameloblastoma; Antigens, Neoplasm; Biomarkers, Tumor; Carcinoembryonic Antigen; Dentigerous Cyst; Humans; Immunohistochemistry; Keratins; Membrane Glycoproteins; Mouth Mucosa; Mucin-1; Odontogenic Cysts; Odontogenic Tumors; S100 Proteins; Skin; Skin Neoplasms

Seventeen cases of desmoplastic ameloblastoma were examined immunohistochemically. Immunoperoxidase techniques were applied for detection of keratin, desmin, vimentin and S-100 protein expression in these tumors. The tumor epithelium of desmoplastic ameloblastoma exhibited weak, focal, inconstant keratin staining, weak, variable expression of S-100 protein, desmin immunoreactivity of mild to moderate intensity and vimentin non-reactivity. The pertinent literature on the immunohistochemistry of ameloblastomas is briefly reviewed.

Topics: Adult; Ameloblastoma; Desmin; Female; Humans; Immunoenzyme Techniques; Immunohistochemistry; Intermediate Filament Proteins; Intermediate Filaments; Jaw Neoplasms; Keratins; Male; Middle Aged; Neoplasm Proteins; S100 Proteins; Vimentin

Granular cell ameloblastoma (GCA) is a well recognized variant of follicular ameloblastoma with extensive granular cell change. In contrast, plexiform granular cell odontogenic tumor (PGCOT) is a rare and recently described lesion characterized histologically by a monophasic plexiform pattern of granular cells. In this paper, two cases of an unusual granular cell odontogenic tumor exhibiting combined features of these two entities are described along with their immunohistochemical characteristics. The granular cells of both the GCA and PGCOT areas showed similar patterns of expression for keratin and S-100, which differed from those of typical ameloblastoma. No reactivity for desmin or vimentin was noted. The histomorphologic and immunohistochemical features of these hybrid tumors suggest that the granular cells present have a common origin, most probably the odontogenic epithelium.

Topics: Adult; Ameloblastoma; Desmin; Female; Granular Cell Tumor; Humans; Immunoenzyme Techniques; Immunohistochemistry; Keratins; Mandibular Neoplasms; Middle Aged; Neoplasm Proteins; Odontogenic Tumors; S100 Proteins; Vimentin

To gain more insight into the differentiation characteristics of the epithelial cells of the adamantinoma of the long bones, we studied the specific keratin immunoreactivity pattern using monoclonal antibodies on 34 primary, recurrent, or metastatic specimens of 22 patients. The results revealed the widespread presence of keratins 14 and 19 in all specimens studied; 74% showed immunoreactivity of keratin 5, and focal staining of keratin 17 was detected in 50%. Keratins 7 and 13 were found in three adamantinoma specimens. This keratin immunoreactivity pattern was independent of histologic subtype, despite marked variety in differentiation pattern, suggesting a common histogenesis for all subtypes of adamantinoma. Furthermore, the pattern was conserved both in local recurrences and in metastasis. The major pattern found in our study differs significantly from other bone and soft tissue tumors with known epithelial characteristics, e.g., synovial sarcomas, chordomas, and epithelioid sarcomas, in that it lacks immunoreactivity of keratins 8 and 18. Our results suggest a basal epithelial cell-like differentiation of adamantinomas.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Antibodies, Monoclonal; Bone Neoplasms; Cell Transformation, Neoplastic; Child; Child, Preschool; Female; Humans; Immunohistochemistry; Keratins; Male; Middle Aged; Neoplasm Recurrence, Local

A clinicopathological and immunohistochemical study of 12 cases of osteofibrous dysplasia (OFD), two cases of differentiated adamantinoma, and five cases of adamantinoma of long bones is presented. Although OFD and differentiated adamantinoma showed similar radiologic findings, differentiated adamantinoma was more likely to be a recurrent lesion than osteofibrous dysplasia and seemed to require a more extensive surgical procedure. Immunohistochemically, cytokeratin- and vimentin-positive cells were seen in both OFD and differentiated adamantinoma. The positive cells were scattered in the former, and were both scattered and nest-like in the latter. Both these lesions, however, were negative for epithelial membrane antigen. Excluding two cases of Ewing-like adamantinoma, the other three cases of adamantinoma were also positive for cytokeratin and vimentin. These results suggest that these three lesions share the same histogenetic origin. The two cases of Ewing-like adamantinoma differ from tibial adamantinoma in their radiological, histological and immunohistochemical aspects, and seem to constitute a distinct variant of adamantinoma with a different histogenesis.

Topics: Adolescent; Adult; Ameloblastoma; Bone Neoplasms; Cell Nucleus; Child; Cytoplasm; Epithelium; Female; Fibrous Dysplasia of Bone; Humans; Immunohistochemistry; Keratins; Male; Middle Aged; Osteoblasts; Osteoclasts; Radiography; Tibia; Vimentin

Immunohistochemical localization of two enamel proteins, amelogenin and enamelin, in comparison with that of keratin, was determined in odontogenic tumors and the allied lesions in order to verify functional differentiation of the tumor cells as ameloblasts. Amelogenin and enamelin were demonstrated in small mineralized foci and in the tumor cells surrounding them in adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), and calcifying odontogenic cyst (COC). Hyaline droplets in AOT showed positive staining for both enamel proteins. These mineralized and hyaline materials were not positive for keratin, although tumor cells were positive. On the other hand, no immunoreaction for enamel proteins was obtained in ameloblastoima and odontogenic epithelial cell nests within myxoma and epulis. The results suggest that tumor cells of AOT and CEOT and lining epithelial cells of COC show ameloblastic differentiation in part, but that ameloblastoma cells do not attain functional matauration as secretory phase ameloblasts.

Topics: Ameloblastoma; Ameloblasts; Amelogenin; Animals; Cattle; Cytoplasm; Dental Enamel Proteins; Epithelium; Gingival Neoplasms; Humans; Hyalin; Immunoenzyme Techniques; Immunohistochemistry; Keratins; Odontogenic Tumors; Polyps; Tooth Germ

Keratin expression was studied immunohistochemically in 27 ameloblastomas using polyclonal antibody against wide-spectrum keratins (TTL) and monoclonal antibodies against lower- and higher-molecular-weight keratins (PKK1 and KL1), respectively, to clarify the tumor differentiation. Reactions with TTL and KL1 antibodies were generally positive in the stellate cells of the follicular or acanthomatous ameloblastomas. Cell nests of the basal cell type were positive for PKK1. On the other hand, the reactions with TTL or KL1 in the plexiform type were generally weak or absent. From these facts, it was concluded that the follicular, as well as acanthomatous, ameloblastoma is liable to undergo squamous differentiation, whereas the plexiform ameloblastoma remains in primitive stage of tumor differentiation.

Topics: Ameloblastoma; Antibodies; Antibodies, Monoclonal; Cell Nucleus; Cell Transformation, Neoplastic; Cytoplasm; Epithelium; Gingiva; Humans; Immunoenzyme Techniques; Keratins

A case of papilliferous keratoameloblastoma is reported which is only the second ever documented. The patient was a 76-yr-old black woman with a large expansile multilocular radiolucency of the body, angle and ramus of the mandible. Histologically the lesion consisted of sheets of cystic follicles filled with necrotic debris and sometimes parakeratin. The vast majority of the follicles were lined by a papilliferous epithelium consisting of large rounded cells with centrally placed nuclei. True papillary projections with cores of connective tissue were also present. The remainder of the follicles were lined by a thin parakeratinising stratified squamous epithelium. Histological features characteristic of ameloblastoma were absent. Final classification of these lesions will have to await the reporting of further cases.

Topics: Aged; Ameloblastoma; Connective Tissue; Epithelium; Female; Humans; Keratins; Mandibular Neoplasms; Necrosis

The binding sites for Ulex europaeus agglutinin I (UEA-I), Bandeirea simplicifolia agglutinin I (BSA-I), and peanut agglutinin (PNA) were comparatively examined in the surgical materials from 41 cases of cystic and solid ameloblastomas and 42 cases of non-neoplastic odontogenic cysts including dentigerous cyst, odontogenic keratocyst, and radicular cyst. In non-neoplastic cysts, most of epithelial lining layers gave positive binding with UEA-I and BSA-I. However, no positive reactions were obtained for these two lectins in the epithelial components of ameloblastoma, except for limited UEA-I binding to markedly keratinized tumor cells in four cases. PNA binding was irregular and did not make any clear distinction between ameloblastomas and cysts. The results suggest that the lectin staining for UEA-I and BSA-I is a useful histologic aid for differential diagnosis between cystic ameloblastoma and non-neoplastic jaw cysts.

Topics: Ameloblastoma; Biomarkers, Tumor; Dentigerous Cyst; Diagnosis, Differential; Endothelium, Vascular; Epithelium; Humans; Immunoenzyme Techniques; Jaw Neoplasms; Keratins; Lectins; Odontogenic Cysts; Peanut Agglutinin; Plant Lectins; Radicular Cyst

Topics: Ameloblastoma; Dentigerous Cyst; Diagnosis, Differential; Female; Humans; Keratins; Middle Aged; Odontogenic Cysts; Odontogenic Tumors; Radicular Cyst; Radiography

In situ and Northern hybridization was carried out to study cytokeratin (Ck) 1, 4, 8, 18, and 19 and vimentin (Vim) gene expression in 13- to 24-week-old human fetal tooth germs, including overlying oral epithelium and odontogenic tumors (N = 6) of epithelial (ameloblastoma) and epithelial-ectomesenchymal (ameloblastic fibroma) origin. The results were compared with immunocytochemistry using monoclonal antibodies. A relatively strong expression of simple epithelial Ck 19 mRNA, together with low, but significant expression of Ck 8 and 18 mRNAs, was demonstrated in all normal and neoplastic odontogenic epithelia studied. Transcripts for squamous differentiation marker, Ck 4, and for terminal differentiation marker, Ck 1, were detected suprabasally in the fetal oral epithelium, focally in the dental lamina but not in the enamel organ. Ck 4 mRNA was expressed variably in most odontogenic tumors studied, whereas Ck 1 mRNA was detected in one ameloblastoma only. Vim mRNA was not found in the fetal oral epithelia, dental lamina or the enamel organ, but a distinct immunoreactivity with monoclonal antibodies to Vim was seen in the stellate reticulum cells of the enamel organ. The epithelium of most ameloblastomas showed a focal Vim mRNA and polypeptide expression. In addition to Vim, the neoplastic ectomesenchymal cells of ameloblastic fibroma coexpressed low amounts of simple epithelial Cks 8, 18, and 19. The results indicate that the differentiation and cytoskeletal gene expression programs of odontogenic epithelia upon neoplastic transformation are not fully retained. Most ameloblastomas and ameloblastic fibromas show differentiation parameters reminiscent of dental lamina. Ameloblastomas seem to form a heterogenous group of tumors, which may originate from odontogenic epithelial cells at various differentiation levels. The origin of ameloblastic fibroma is more closely related to the tooth germ proper.

Topics: Ameloblastoma; Dental Enamel; Epithelium; Female; Gene Expression; Humans; Keratins; Mouth Mucosa; Odontogenic Tumors; Pregnancy; RNA, Messenger; Tooth; Vimentin

A case is described of ameloblastoma of maxilla presenting with numerous calcified keratin pearls. The significance of cellular variation in relation to the behavioural potential of the ameloblastoma in general is briefly discussed.

Topics: Adult; Ameloblastoma; Calcinosis; Humans; Keratins; Male; Maxillary Neoplasms

A rare case of granular cell ameloblastoma in the anterior mandible of a 59-year-old man has been studied by light and electron microscopy. In some areas, the tumor was very similar to an oncocytoma (oxyphilic adenoma). Almost all tumor cells were full of eosinophilic granules, whereas in the common type of granular cell ameloblastoma, only the cells located in the central portion of the tumor are granular.

Topics: Adenoma; Ameloblastoma; Cell Nucleus; Cytoplasm; Cytoplasmic Granules; Diagnosis, Differential; Epithelium; Humans; Keratins; Male; Mandibular Neoplasms; Middle Aged

Monoclonal antibodies (Mab) were used to study the expression of cytokeratins and vimentin in various histological types of ameloblastoma and in human fetal tooth germ. The ameloblastoma and the tooth germ epithelia showed characteristics of both simple glandular and stratified squamous epithelial cells. Cytokeratin No. 18 was detected focally in most ameloblastomas studied but not in fetal odontogenic epithelia. Cytokeratins Nos. 8 and 19 were expressed in all epithelial elements of ameloblastomas and tooth germs. Only two tumors showed focally characteristics of keratinizing epithelia also seen in dental lamina but not in the enamel organ. All tumors except the granular cell ameloblastoma showed a variable coexpression of vimentin and cytokeratins in their neoplastic epithelia. A similar coexpression was detected in the stellate reticulum cells of the developing tooth. Ameloblastoma and human tooth germ epithelia share complex pattern of cytokeratin polypeptides together with coexpression of vimentin. The results strongly support the theory that ameloblastomas are of odontogenic origin and not direct derivatives of basal cells of oral epithelium or epidermis.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Antibodies, Monoclonal; Cytoskeleton; Enamel Organ; Female; Fetus; Fluorescent Antibody Technique; Humans; Intermediate Filaments; Keratins; Male; Middle Aged; Tooth Germ; Vimentin

Granular cells can occur in various odontogenic and non-odontogenic tumours. 5 granular cell lesions, one granular cell ameloblastoma, one so-called granular cell ameloblastic fibroma and three granular cell tumours were examined immunohistochemically for the intermediate filaments cytokeratin, vimentin, desmin, neurofilaments and the neural markers NSE and S-100 protein. The granular cell tumors (granular cell myoblastoma) showed positive staining for vimentin and S-100 protein. Only vimentin could be demonstrated in the granular cells of the so-called granular cell ameloblastic fibroma, whereas the granular cell ameloblastoma showed positive staining only for cytokeratin. A positive reaction with S-100 protein was not found in any of the odontogenic tumours. In our opinion the mesenchymal odontogenic granular cell is a fibroblast, whereas the epithelial granular cell is derived from enamel epithelium. The term "granular cell ameloblastic fibroma" is a misnomer, as a number of these tumours are probably central odontogenic fibromas exhibiting granular cell transformation.

Topics: Adult; Ameloblastoma; Epithelium; Female; Gingival Neoplasms; Humans; Immunoenzyme Techniques; Immunohistochemistry; Keratins; Male; Middle Aged; Odontogenic Tumors; Phosphopyruvate Hydratase; S100 Proteins; Vimentin

Complementary DNA (cDNA) clones corresponding to the 55 kDa (K 14) and 59 kDa (K 10) keratins were used as probes for in situ hybridization analysis for the expression of keratin genes in human ameloblastomas and in oral mucosa. Transcripts for either the K 14 keratin or the K 10 keratin were restricted in their spatial distribution within stratified epithelia consistent with the stage of differentiation of the keratinocyte: the K 14 keratin gene transcript was restricted to the basal cell layers of the mucosa, while the K 10 keratin transcript was expressed predominantly in suprabasal cells, within the granular and prickle layers. In contrast, only the K 14 keratin transcript could be identified within the epithelial cells of human ameloblastomas. The differentiation-specific keratin transcript (K 10) was not present at detectable levels in this type of odontogenic tumors. In an atypical, infiltrating ameloblastoma, neither the K 10 nor the K 14 transcript could be identified. Granular cells within one ameloblastoma expressed the K 14 transcript. A detailed examination of the pattern of gene expression in these unique tumors may lead to a better understanding of their pathogenesis.

Topics: Ameloblastoma; Autoradiography; Cytoplasm; Epithelium; Gene Expression Regulation; Histocytochemistry; Humans; Keratins; Nucleic Acid Hybridization; RNA Probes; RNA, Messenger; RNA, Neoplasm; Transcription, Genetic

Ten cases of ameloblastoma including a case of gingival origin and a case of atypical ameloblastoma were studied immunohistochemically, especially with monoclonal and polyclonal anti-keratin antibodies. Stellate reticulum cells reacted strongly with monoclonal and polyclonal anti-keratin antibodies but columnar cells were reacted weakly. The level of keratinization of columnar cells was similar to that of the basal cell layer of the gingival squamous epithelium. Our immunohistochemical studies suggested that the process of keratinization-ameloblastoma follows the sequence of 1) cuboidal cells 2) columnar cells 3) stellate reticulum cells and 4) metaplastic squamous cells. The findings also disclosed the epithelial nature of granular cells. The reactivity of the components of atypical ameloblastoma differed from that of other cases. Other positive "markers" in ameloblastomas included CEA and CA19-9, but no particular histologic differences were observed between positive and negative cases.

Topics: Adult; Ameloblastoma; Antibodies, Monoclonal; Female; Gingiva; Gingival Neoplasms; Humans; Immunoenzyme Techniques; Keratins; Male; Middle Aged

Immunostaining with monoclonal antibodies was used to study and compare the cytokeratin content of odontogenic cysts and normal gingival epithelium. Two monoclonal antibodies, PKK2 and KA1, stained the whole epithelium in all cyst samples. In gingiva, PKK2 gave a suprabasal staining and KA1 reacted with all epithelial cell layers. Antibodies PKK1, KM 4.62 and KS 8.12 gave a heterogeneous staining in follicular and radicular cysts. In keratocysts and in gingiva PKK1 and KM 4.62 reacted mainly with basal cells and KS 8.12 gave a suprabasal staining. Antibodies reacting with the simple epithelial cytokeratin polypeptide No. 18 (PKK3, KS 18.18) recognized in gingiva only solitary cells compatible with Merkel cells. In a case of follicular ameloblastoma a distinct staining of tumor epithelium was revealed with these antibodies. In 2 follicular cysts, but not in other cyst types, a layer of cytokeratin 18-positive cells was revealed. KA5 and KK 8.60 antibodies, reacting exclusively with keratinizing epithelia, including normal gingiva, gave no reaction in radicular cysts, keratocysts and ameloblastoma. Two of the follicular cysts, were negative for PKK3 and KS 18.18, but reacted strongly with KA5 and KK 8.60. The present results show that odontogenic jaw cysts have distinct differences in their cytokeratin content. With the exception of some follicular cysts, they lack signs of keratinizing epithelial differentiation. Only follicular cysts appear to share with some types of ameloblastoma the expression of cytokeratin polypeptide No. 18.

Topics: Ameloblastoma; Antibodies, Monoclonal; Epithelium; Follicular Cyst; Gingiva; Humans; Jaw Diseases; Jaw Neoplasms; Keratins; Microscopy, Fluorescence; Odontogenic Cysts; Radicular Cyst

The relationship of the keratocyst antigen (KCA), the soluble component present in most keratocyst fluids, and keratin, was studied with immunofluorescence microscopy comparing their distribution in developing mouse embryonic teeth and in human ameloblastomas. In these tissues both molecules showed a strong codistribution in epithelial cells. In the embryonic teeth both molecules were present in the stratum intermedium cells between the stellate reticulum cells and ameloblasts, but the secretory ends of the ameloblasts showed fluorescent staining only for keratin. The relationship was further investigated by comparing the physicochemical characteristics of KCA and keratin. Results on immunoblotting and two-dimensional gel electrophoresis showed that KCA existed in keratocyst fluid as a 60-68,000 dalton polypeptide with an isoelectric point of pI 6.8. Immunoblotting analysis of various isolated keratins revealed a typical polypeptide pattern of each keratin when anti-KCA antiserum was used for staining. These findings suggest that KCA and keratin are related molecules and that KCA may be a soluble component of keratin.

Topics: Ameloblastoma; Animals; Antigens; Collodion; Electrophoresis, Polyacrylamide Gel; Fluorescent Antibody Technique; Humans; Keratins; Mice; Odontogenic Cysts; Paper; Staining and Labeling; Tooth Germ

This study describes the distribution of type 1 and type 2 blood group carbohydrate chains in human normal and pathological odontogenic epithelia and in epithelia of human oral mucosa. Odontogenic epithelium was examined from 12 fetal tooth germs, 25 ameloblastomas, 13 odontogenic keratocysts, 13 follicular cysts and 13 radicular cysts. Oral mucosal epithelia was studied from 12 fetuses and 10 adults. Cell surface carbohydrates were detected using antibodies with reactivity for the blood group antigens A, B, type 1 chain Lea and type 2 chain H by an immunofluorescence technique. The expression of Lea and H type 2 chain in fetal palatal epithelium and only H type 2 chain in adult palatal epithelium suggests that a change in synthesis of blood group chains occurs during development. Type 2 blood group chains (antigen H) were found in fetal tooth germs, type 1 (Lea) in ameloblastomas and both type 1 and type 2 in odontogenic cysts. These results indicate that a modulation in synthesis of blood group carbohydrates has occurred in ameloblastomas and odontogenic cysts as compared with the cells from which the lesions presumably are developed. It is suggested that ameloblastomas may be distinguished from odontogenic cysts by the inability of ameloblastomas to synthesize type 2 blood group chains and antigens A and B.

Topics: ABO Blood-Group System; Adolescent; Adult; Aged; Ameloblastoma; Antibodies, Monoclonal; Dentigerous Cyst; Epithelium; Female; Fetus; H-2 Antigens; Humans; Keratins; Lewis Blood Group Antigens; Male; Middle Aged; Mouth Mucosa; Odontogenic Cysts; Odontogenic Tumors; Radicular Cyst; Tooth Germ

The light microscopic, ultrastructural, and immunohistochemical characteristics of two tibial adamantinomas are presented. The immunohistochemical studies utilized specific antibodies against Factor VIII-related antigen and keratin protein, considered as markers for endothelial and epithelial cells, respectively. These revealed positive staining for keratin in the tumor cells of both cases, whereas Factor VIII was not found in either. Ultrastructurally, both tumors had tonofilaments, desmosomes, gap junctions, microvillous-like projections, and basement membranes. Patient 1 had disease that was histologically of the classic spindle cell type; the disease of Patient 2 was atypical and closely resembled an epithelioid angiosarcoma. Immunohistochemical and ultrastructural findings in each case indicate an epithelial component in tibial adamantinoma.

Topics: Adolescent; Ameloblastoma; Antigens; Bone Neoplasms; Factor VIII; Female; Histocytochemistry; Humans; Immunoenzyme Techniques; Keratins; Male; Microscopy, Electron; Tibia; von Willebrand Factor

The nature and location of intermediate filament proteins (IFP) may provide new insights into the origin and differentiation of neoplastic cells. An immunofluorescent study of these IFP in a case of a granular cell ameloblastoma revealed that all tumor cells contained the IFP keratin. Some granular cells, however, also contained the IFP vimentin, which is considered specific for mesenchymal tissues only. The implications of these observations are discussed. Study with monoclonal antibodies indicated the origin of the ameloblastoma from non-keratinized squamous epithelium. A comparison of the anti-keratin immunofluorescence pattern of the ameloblast-like cells in the present tumor with ameloblasts in the tooth germ revealed no similarities, indicating that despite some resemblance of the peripheral columnar cells to ameloblasts, these cells differ in other aspects.

Topics: Aged; Ameloblastoma; Animals; Antibodies, Monoclonal; Female; Fluorescent Antibody Technique; Histocytochemistry; Humans; Intermediate Filament Proteins; Keratins; Mandibular Neoplasms; Rabbits; Vimentin

The nature of the tumor cells in 5 cases of ameloblastomas was studied by immunohistochemistry, and the findings were compared with developing mouse and human teeth as well as with 5 cases of carcinomas in the oral region. The antigens investigated were keratin, an intracellular cytoskeletal protein typical of epithelial cells, and laminin, an extracellular matrix protein found in basement membranes. Our results show that keratin is expressed by all types of epithelial cells in ameloblastomas as well as in the epidermoid carcinomas, and developing teeth. The epithelial, keratin-positive tumor islands in the ameloblastomas were surrounded by a continuous line of laminin, in a pattern similar to that seen in developing tooth. Laminin was seen also around the epidermoid carcinomas but large areas devoid of laminin were constantly seen between the stroma and the neoplastic epithelium. This indicates a lack of proper basement membrane formation by the malignant epidermoid carcinomas. This may be due either to a diminished production or an increased degradation of basement membrane proteins by the carcinoma cells. Our results are in line with suggestions that ameloblastomas are derived from odontogenic epithelial cells. Immunostaining for keratin does not distinguish between carcinomas and the ameloblastomas. However, visualization of basement membrane proteins such as laminin can apparently be used in the differential diagnosis between ameloblastomas and carcinomas.

Topics: Ameloblastoma; Animals; Basement Membrane; Carcinoma, Squamous Cell; Diagnosis, Differential; Fluorescent Antibody Technique; Histocytochemistry; Immunoenzyme Techniques; Keratins; Laminin; Mice; Mouth Neoplasms; Tooth

Adamantinoma of the tibia was studied by electron microscopy and immunohistochemistry. The palisading tumor cell nests were invested with a continuous basal lamina. The peripheral tumor cells of the nests were bound to each other by desmosomes. Intermediate densities in the form of incomplete hemidesmosomes were seen in the outermost cells of the nests. There were two types of cytoplasmic filaments--tonofilaments and actinlike microfilaments. The latter occurred predominantly in the cytoplasm beneath the plasma membrane of the outermost cells of the nests. This could be implicated in the motile and invasive properties of the tumor cells. Immunohistochemic stains localized keratin in most tumor cells. Coagulation factor VIII-related antigen was localized in the endothelial cells of the stroma but not in the tumor cells. These findings indicate the appendicular adamantinoma to be of ectodermal epithelial origin, most likely a variant of basal cell carcinoma.

Topics: Aged; Ameloblastoma; Antigens; Bone Neoplasms; Cytoskeleton; Factor VIII; Histocytochemistry; Humans; Keratins; Male; Microscopy, Electron; Tibia; von Willebrand Factor

The histologic similarities between the craniopharyngioma and the ameloblastoma are well recognized and supported by their common embryologic origin from oral ectoderm. Differences in these lesions include a greater tendency for craniopharyngiomas to be cystic and form ghost cells and calcifications. The keratinizing and calcifying odontogenic cyst (KCOC), a lesion that features proliferating ameloblastic epithelium, ghost keratin, calcification, and cyst formation, may more precisely mimic the craniopharyngioma. The histologic features of twenty-seven craniopharyngiomas were studied. Twenty cases resembled KCOC microscopically. Two examples duplicated the histologic features of infiltrative ameloblastoma, while five showed characteristics of both lesions. This study shows that the range of histologic features in craniopharyngioma includes and spans both odontogenic lesions but more often simulates KCOC. The results suggest that the KCOC and the ameloblastoma may be closely related developmentally.

Topics: Ameloblastoma; Craniopharyngioma; Diagnosis, Differential; Epithelium; Humans; Keratins; Metaplasia; Odontogenic Tumors; Pituitary Neoplasms

Ameloblastomas reviewed in this report were locally invasive neoplasms arising from the epithelial structures of the dental lamina, and were characterized histologically by features which are unique to dental lamina epithelium. These include the formation of epithelial sheets in which the cells nearest the stroma form a palisading row aligned perpendicularly to the basement membrane and the cells toward the center separate from each other except at desmosomal attachments. This is similar to the appearance of th stellate reticulum of the early enamel organ. Other features include epithelial cords which branch and interconnect, and the intimate association of epithelial structures and collagenous matrix. In our dogs, other important features were the deposition of inclusions similar in appearance to enamel matrix between the cells of the epithelium and various degrees of keratinization. All ameloblastomas studied were locally invasive tumors which occurred at various sites on the gingiva. The average age of the dogs was 8.7 years and the age range was three to 13 years. Radiographically, all of the tumors studied resulted in periodontal osteolysis. Six dogs were treated with radiation therapy, but details of the radiotherapy of two dogs could not be located. Of the other four dogs, one is alive 48 months after radiotherapy with no evidence of tumor regrowth. Regrowth of the oral tumor was apparent in the other three dogs six, 21, and 34 months after completion of the radiotherapy. Three dogs were treated by radical mandibulectomy; all are alive with no evidence of tumor recurrence at two, 20, and 28 months postoperatively. Two dogs had local dissection (curettage) of tumors and the tumors recurred at 12 and 15 months after surgery. One dog was euthanatized after diagnosis of the oral tumor because of a progressive neuropathy.

Topics: Ameloblastoma; Animals; Dog Diseases; Dogs; Epithelium; Female; Gingiva; Gingival Neoplasms; Keratins; Male

Topics: Adolescent; Ameloblastoma; Dentigerous Cyst; Female; Humans; Keratins; Mandibular Neoplasms

A case of an extraosseous ameloblastoma occurring in a 33-year-old woman has been described. Of the 11 cases documented in the literature, only nine fulfill the histologic and clinical criteria for a true peripheral ameloblastoma. In contrast to the intraosseous ameloblastoma, the diagnosis of extramedullary or peripheral ameloblastoma implies a less aggressive neoplasm that can be treated by a more conservative surgical approach.

Topics: Adult; Ameloblastoma; Connective Tissue; Female; Gingival Neoplasms; Humans; Keratins

The potential of odontogenic epithelium to keratinize in the form of ghost cells is demonstrated in the histologic variants of a number of odontongic tumors. Although the cells lack keratohyaline granules, they do contain abundant tonofilaments and probably represent an altered form of keratin. The presence of this material in odontogenic tumors does not appear to alter clinical occurence or clinical behavior.

Topics: Adolescent; Adult; Aged; Ameloblastoma; Cell Membrane; Child; Epithelial Cells; Epithelium; Female; Gingival Neoplasms; Humans; Keratins; Male; Mandibular Neoplasms; Maxillary Neoplasms; Middle Aged; Odontogenic Tumors; Odontoma; Organoids

Topics: Ameloblastoma; Diagnosis, Differential; Humans; Keratins; Mandibular Neoplasms; Neoplasm Recurrence, Local; Odontogenic Cysts; Radiography; Root Resorption

Topics: Ameloblastoma; Dentistry; Keratins; Odontogenic Tumors

Topics: Adolescent; Ameloblastoma; Fetus; Geriatrics; Gingival Diseases; Gingivectomy; Humans; Keratins; Odontogenesis; Odontogenic Cysts; Pathology; Pathology, Oral; Radiography, Dental; Surgery, Oral