bromochloroacetic-acid and Neoplasm-Regression--Spontaneous

We describe an unusual case of metastatic choriocarcinoma of the pancreas arising from a regressing testicular mixed germ cell tumor that clinically mimicked a primary pancreatic tumor. A 54-year-old male presented with a 2-month history of progressive upper abdominal pain, weight loss, and jaundice. He also had a history of recurrent epididymitis associated with the presence of a right testicular mass shown to be cystic by ultrasound and stable for at least 10 years. A computed tomography scan showed an isolated 6 cm mass in the head of the pancreas. A pancreaticoduodenectomy was performed. Upon histological examination, the pancreatic tumor showed extensive hemorrhage and necrosis. In the viable area, the tumor was composed of an intimate mixture of mononuclear cytotrophoblast cells and multinucleated syncytiotrophoblasts with vascular invasion. These characteristic features led to the correct diagnosis on frozen section. The cytology of the tumor was nonspecific and suggested undifferentiated carcinoma of the pancreas. The trophoblastic origin of the tumor cells was confirmed by immunohistochemistry staining. The testicular mass showed a regressed mixed germ cell tumor of predominantly seminoma with focal teratoma but without a choriocarcinoma component. In conclusion, we present a rare and unusual case of a regressing testicular mixed germ cell tumor that presented as a primary pancreatic tumor. Cytological features of the pancreatic mass were not specific and raised the possibility of a primary undifferentiated carcinoma of the pancreas. Characteristic histological features of choriocarcinoma led to the correct diagnosis on frozen section. Subsequent resection of the testicular mass confirmed the presence of a cystic and scarring (regressing) mixed germ cell tumor but without evidence of choriocarcinoma.

Topics: Biomarkers; Choriocarcinoma; Chorionic Gonadotropin; Germinoma; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Keratins; Male; Middle Aged; Neoplasm Regression, Spontaneous; Pancreas; Pancreatic Neoplasms; Testicular Neoplasms; Testis

The immunophenotype of tumor cells and inflammatory infiltrate associated with cutaneous melanocytic lesions (29 melanocytomas, two malignant melanomas, and 23 residual lesions) from 54 adult Iberian and Iberian x Duroc pigs were examined using a panel of nine antibodies. All neoplastic cells were vimentin+, cytokeratin-, and alpha-1-antitrypsin- and the majority were S100+, whereas all pigmented macrophages were vimentin+, cytokeratin-, and S100- and most expressed alpha-1-antitrypsin. Regressing tumors were characterized by zones with low density of neoplastic cells accompanied by heavy infiltration of CD3+ T lymphocytes, whereas zones with high density of neoplastic cells showed very low numbers of CD3+ T lymphocytes. The infiltrate of CD79a+ B cells and IgG, IgM, and IgA plasma cells was low. The majority of lymphocytes of the peri- and intratumoral infiltrate were major histocompatibility complex class II+, but neoplastic cells did not express class II antigen. The 17 residual lesions examined were composed of macrophages containing abundant melanin pigment and low to moderate numbers of CD3+ T lymphocytes. The results of the present study suggest that the local cellular immune response plays a crucial role in the host response that induces regression of cutaneous melanomas and melanocytomas of the Iberian and crossbred Iberian x Duroc pigs.

Topics: alpha 1-Antitrypsin; Animals; Antigens, CD; B-Lymphocytes; CD3 Complex; CD79 Antigens; Histocompatibility Antigens Class II; Immunohistochemistry; Keratins; Melanocytes; Melanoma; Neoplasm Regression, Spontaneous; Plasma Cells; Receptors, Antigen, B-Cell; S100 Proteins; Skin Neoplasms; Swine; Swine Diseases; T-Lymphocytes; Vimentin

Keratoacanthomas are benign skin tumors that grow rapidly but eventually regress. They occur most commonly in sun-exposed skin and are histologically remarkably similar to squamous cancers. Since mutations of the p53 tumor suppressor gene are found frequently in cutaneous squamous cell carcinomas, we hypothesized that p53 mutations might contribute to the development of keratoacanthomas. To address this question, we did p53 immunohistochemistry with a polyclonal rabbit antiserum, CM-1, that binds both mutant and wild-type p53 proteins. Although wild-type p53 protein degrades rapidly and is generally undetected by immunohistochemistry, mutant p53 protein has a longer half-life and accumulates to detectable levels. We tested 26 formalin-fixed keratoacanthomas and 4 normal skin biopsies. Positive nuclear staining was detected in 20 of 26 (77%) of the keratoacanthomas and in none of the normal skin samples. Nuclear staining occurred in the outermost layer of the neoplasms and not in the keratin-filled central cores. Since nuclear p53 protein within a cutaneous squamous cell carcinoma usually correlates with missense mutation, these data suggest that p53 mutations contribute to the development of this benign neoplasm. The histologic similarity to squamous cell carcinoma and the accumulation of p53 protein suggest progression toward malignancy, but the invariable regression of these tumors suggests an arrest at some point in multistage carcinogenesis. If this model is correct, then genetic analysis of keratoacanthomas may provide clues to the later stages of squamous carcinogenesis including local invasion and metastasis.

Topics: Animals; Carcinoma, Squamous Cell; Cell Nucleus; Coloring Agents; Disease Progression; Fixatives; Formaldehyde; Genes, p53; Half-Life; Humans; Image Processing, Computer-Assisted; Immunohistochemistry; Keratins; Keratoacanthoma; Mutation; Neoplasm Regression, Spontaneous; Rabbits; Remission, Spontaneous; Skin; Skin Neoplasms; Sunlight; Tumor Suppressor Protein p53