Malignant melanoma of the rectum presenting as cloacogenic polyp: a case report.

Mucosal malignant melanomas are uncommon. It is rare for a primary mucosal melanoma to occur in the anorectal region. Anorectal polypoid mucosal prolapse however, is a relatively common condition. We report a case of malignant melanoma presenting as mucosal prolapse and inducing changes similar to inflammatory cloacogenic polyp.

Low-grade myofibroblastic sarcoma of the piriform fossa: a case report with a literature review of a tumour with a predilection for the head and neck.

A low-grade myofibroblastic sarcoma was removed from the pyriform fossa of a 44-year-old man. It recurred 4 years later and was removed radically through an incision in the neck. There has been no further recurrence after 11 years.

Necrobiotic palisading granulomas associated with breast carcinoma.

AIMS: The presence of granulomas within the stroma of carcinomas and in the lymph nodes draining carcinomas has been well described. To date, however, there have been few studies examining the occurrence and relevance of necrobiotic granulomas occurring in association with breast carcinoma. METHODS/RESULTS: Four cases of breast carcinoma with necrobiotic granulomas were examined using periodic acid Schiff and Ziehl Neelsen stains for fungi and tubercle bacilli and with immunohistochemistry using CAM 5.2, cytokeratin 7, and cytokeratin AE1/3 for tumour cells. In one case the stroma was involved, in the other three cases the lymph nodes contained necrobiotic granulomas. In two of the cases, one with stromal and one with lymph node involvement, the necrobiotic granulomas contained necrotic tumour cells. CONCLUSION: In this study the features of four cases of breast carcinomas with necrobiotic granulomas are examined and their relevance explored. Close scrutiny of such granulomas is necessary to avoid underdiagnosis of metastatic disease.

High-grade carcinomas of the breast showing patterns of mixed ductal and myoepithelial differentiation (including myoepithelial cell-rich carcinoma of the breast).

AIMS: To assess the clinical, morphological and immunophenotypic characteristics of breast carcinomas showing patterns of mixed epithelial and myoepithelial differentiation. METHODS AND RESULTS: Included in the study were four carcinomas containing a mixed population of epithelial and myoepithelial cells identified using morphological features at the light microscopic level which were found amongst a review of 500 archival cases and two recently accessioned cases. The carcinomas varied in size from 20 to 38 mm and all were grade 3 ductal carcinomas. Most showed nodular and sheet-like cellular aggregates, although one case showed small solid cell aggregates with duct formation. The cells were large, round, polygonal or spindle-shaped and had areas of clear or eosinophilic cytoplasm in variable proportions. Foci of metaplasic carcinoma were present in three cases. All cases showed strong, patchy positivity for cytokeratin (CK)14, calponin, smooth actin and muscle specific actin. Epithelial membrane antigen and CK8 were positive in a similar proportion of cells. One patient died 23 months following diagnosis with metastatic carcinoma, another patient died of unrelated disease and four patients are alive with follow-up ranging from 18 months to 25 years. CONCLUSIONS: High-grade carcinomas of the breast showing patterns of mixed ductal and myoepithelial differentiation may show additional morphological features such as foci of metaplasia and appear to have a good prognosis similar to myoepithelial cell-rich carcinomas. However, young age and lymph node metastasis may portend a worse prognosis.

Post-transplant T-cell lymphoproliferative disorder/T-cell lymphoma: a report of three cases of T-anaplastic large-cell lymphoma with cutaneous presentation and a review of the literature.

AIMS: To report the clinical, pathological and immunohistochemical features of three cases of post-transplant T-cell lymphoproliferative disorder (T-PTLD) T-cell lymphoma with primary cutaneous presentation. METHODS AND RESULTS: Three cases of primary cutaneous post-transplantation anaplastic large-cell lymphomas occurred in renal transplant recipients and were shown to display a T-cell immunophenotype; all were ALK 1 protein and EMA negative and two were Epstein-Barr virus positive using in-situ hybridization. Two displayed a CD4+ phenotype, two were focally CD56+ and all three were negative for the cytolytic enzyme granzyme B. In two cases monoclonality was established by T-cell receptor gene rearrangement study. All presented with nodular cutaneous involvement and all were ultimately fatal. CONCLUSION: T-PTLDs are uncommon histological subtypes both in a general context and associated with cutaneous presentation. Our findings suggest clinicopathological and immunophenotypic similarities to primary cutaneous anaplastic large-cell lymphoma but with a progressive clinical behaviour similar to previously reported T-PTLD and to systemic nodal ALK- anaplastic large-cell lymphoma.

Actin filaments in human renal tubulo-interstitial fibrosis: significance for the concept of epithelial-myofibroblast transformation.

Epithelial-myofibroblast transformation has been argued as playing a role in tubulo-interstitial fibrosis. To investigate this hypothesis, we examined 9 renal biopsy specimens from patients with chronic renal disease by light and electron microscopy. In all cases, electron microscopy confirmed light microscope observations in relation to tubulo-interstitial fibrosis-tubular atrophy, accumulation of extracellular matrix and of mesenchymal interstitial cells, and infiltration by inflammatory cells. Tubular epithelial cells (TECs) contained bundles of actin filaments: mostly lacking the focal densities typical of smooth-muscle myofilaments. The interstitium contained collagen and inflammatory cells. Some endothelial cells showed bundles of myofilaments. Free mesenchymal cells in the matrix were spindled and had sparse rough endoplasmic reticulum (rER), small attachment plaques, few actin filaments and no lamina. In one case, myofibroblasts (defined by abundant rER, myofilaments and fibronexuses) were present. Most of the mesenchymal cells, therefore, did not correspond to myofibroblasts, nor to classical fibroblasts because of the sparse rER and the presence of actin filaments. We therefore called these cells myoid stromal cells, regarding them as stromal mesenchymal elements showing partial activation towards a smooth-muscle phenotype. This paper demonstrates a greater phenotypic complexity of actin-containing stromal cells in the interstitium than previously appreciated, with only a minority conforming to true or fully differentiated myofibroblasts. The widespread presence of actin (as filaments or immunoreactivity) in both TECs and interstitial cells, combined with the absence of evidence of intermediate forms or of migration from epithelium into interstitium, may point to epithelium and interstitium as separate targets for actin upregulation as an alternative hypothesis to epithelial-myofibroblast transformation.

Intractable pruritus associated with insulinoma in the absence of multiple endocrine neoplasia: a novel paraneoplastic phenomenon.

Insulinoma is a rare tumour, the main symptoms of which are related to hypoglycaemia. Generalized pruritus has been described in association with the multiple endocrine neoplasia syndrome (MEN II or Sipple's syndrome) as a paraneoplastic phenomenon. Further, pruritus is known to be part of the paraneoplastic syndrome in other solid tumours. This case describes a patient presenting with symptoms of Whipple's triad (hypoglycaemic symptoms during fasting, low fasting blood sugar levels and symptoms relieved by intravenous dextrose). Magnetic resonance scanning and selective mesenteric angiography demonstrated a probable pancreatic neuroendocrine tumour. Pituitary fossa imaging and endocrine profile excluded the MEN I syndrome. Symptoms resolved after surgical removal of the tumour. Histology confirmed a pancreatic neuroendocrine tumour. The association between pruritus and insulinoma appears to be a novel paraneoplastic phenomenon.

Colonic carcinoma with granulomatous (sarcoid) reaction.

A 74 year old man had a right hemicolectomy for a caecal adenocarcinoma. Microscopic examination also revealed non-caseating epithelioid granulomatas within the adjacent stroma and some of these granulomata contained centrally located malignant cells. Granulomatous inflammation was not present within the lymph nodes and the importance of this rare occurrence is discussed.