bromochloroacetic-acid and Myofibroma

Calretinin is an intracellular calcium-binding EF-hand protein of the calmodulin superfamily. It plays a role in diverse cellular functions, including message targeting and intracellular calcium signaling. It is expressed in the mesothelium, mast cells, some neural cells, and fat cells, among others. Because of its relative specificity for mesothelial neoplasms, calretinin is widely used as one of the primary immunohistochemical markers for malignant mesothelioma and in differentiating it from adenocarcinoma. On the basis of our sporadic observation on calretinin immunoreactivity in desmoid fibromatosis, we systematically evaluated calretinin, keratin cocktail (AE1/AE3), and WT1 immunoreactivity in 268 fibroblastic/myofibroblastic neoplasms. Calretinin was observed in 75% (44/58) of desmoid fibromatosis, 50% (21/42) of proliferative fasciitis, 23% (8/35) of nodular fasciitis, 33% (13/40) of benign fibrous histiocytoma, 35% (22/62) of malignant fibrous histiocytoma, and 13% (4/31) of solitary fibrous tumors but not in normal connective tissue fibroblasts at various sites. Keratin AE1/AE3 immunoreactivity was also commonly (6/13) present in the large ganglion-like cells of proliferative fasciitis and sometimes in nodular fasciitis (3/35), solitary fibrous tumor (3/27), and malignant fibrous histiocytoma (9/62). Nuclear immunoreactivity for WT1 or keratin 5 positivity was not detected in myofibroblastic tumors. On the basis of these observations, it can be concluded that calretinin and focal keratin immunoreactivity is fairly common in benign and malignant fibroblastic and myofibroblastic lesions. Calretinin-positive and keratin-positive spindle cells in desmoid and nodular fasciitis or calretinin-positive ganglion-like cells in proliferative fasciitis should not be confused with elements of epithelioid or sarcomatoid mesothelioma. These diagnostic pitfalls can be avoided with careful observation of morphology, quantitative differences in keratin expression, and use of additional immunohistochemical markers such keratin 5 and WT1 to verify true epithelial and mesothelial differentiation typical of mesothelioma.

Topics: Calbindin 2; Cell Nucleus; Diagnosis, Differential; Diagnostic Errors; Fasciitis; Fibromatosis, Aggressive; Histiocytoma, Benign Fibrous; Histiocytoma, Malignant Fibrous; Humans; Keratins; Myofibroma; S100 Calcium Binding Protein G; Solitary Fibrous Tumors; Tissue Array Analysis; WT1 Proteins

Pseudosarcomatous myofibroblastic proliferation of the genitourinary tract is rare and may develop after trauma or spontaneously. The aim of this study was to characterize further the clinicopathological features of these lesions and to examine their relationship to inflammatory myofibroblastic tumour (IMT).. Twenty-seven cases of pseudosarcomatous myofibroblastic proliferation were analysed. There were seven males and 20 females; median age was 37 years (range 16-88). Most lesions were from the bladder (n = 21), while others were in the urethra, vulva, vagina, rectum and retrovesical space. Median tumour size was 30 mm (range 6-120 mm). Seven cases (25%) had a history of prior trauma or surgery. Three cases recurred locally but not destructively. The tumours had fasciitis-like features including bland spindle cells with evenly distributed chromatin, admixed inflammatory cells (mainly lymphocytes) and often a myxoid stroma. Immunohistochemistry showed positivity for smooth muscle actin in 14/20 cases, keratin in 8/19, desmin in 7/20 and anaplastic lymphoma kinase (ALK) in 10/21 cases. Fluorescent in situ hybridization was performed in six ALK+ cases; all were negative for ALK gene rearrangement.. Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract may show ALK immunopositivity but do not show consistent ALK rearrangement. Given subtle morphological differences and more consistently benign behaviour, their relationship to inflammatory myofibroblastic tumour at other sites remains uncertain.

Topics: Actins; Adolescent; Adult; Aged; Aged, 80 and over; Anaplastic Lymphoma Kinase; Desmin; Female; Fibroblasts; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Keratins; Male; Middle Aged; Muscle, Smooth; Myofibroma; Protein-Tyrosine Kinases; Receptor Protein-Tyrosine Kinases; Sarcoma; Urethral Neoplasms; Urinary Bladder Neoplasms