1/2. Angiomyofibroblastoma and aggressive angiomyxoma: two benign mesenchymal neoplasms of the female genital tract. An immunohistochemical study.We describe a rare case of angiomyofibroblastoma (AMF) of the vulva and one case of aggressive angiomyxoma (AAM) of the pelvic region and, with the help of an extensive revision of the literature, we attempt to define their histogenesis and peculiar biological behaviour by an immunohistological evaluation. Our results indicate that AAM, which is characterized by the presence of a high content of glycosaminoglycans in the stroma, expresses uniformly vimentin and hyaluronate receptor CD44, and heterogeneously muscle specific actin (MSA) and desmin, while AMF displays a positive reaction for vimentin, desmin and laminin, and only a weak and heterogeneous positivity for CD44. Both AMF and AAM showed no immunohistochemical reactivity for alpha-smooth muscle actin (ASMA), myoglobin, cytokeratin, collagen type iv, CD68 and S-100. The stromal cells of AAM were negative for laminin. These findings support the suggestion of an origin of the two entities by a common myofibroblastic progenitor, which normally occurs in the lower female genital tract and subsequently undergoes a neoplastic transformation. The expression of CD44 by AAM, which has never been reported before, could be responsible for its more aggressive behaviour, because this receptor is able to mediate migration of neoplastic cells on a hyaluronate rich extracellular matrix. It is speculated that the neoplastic cell of the AAM and AMF of the vulva is a specific myofibroblast which probably arises from undifferentiated mesenchymal cells normally occurring in the lower female genital tract.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
2/2. Malignant myoepithelioma of the vulva resembling a rhabdoid tumour.AIMS: We report an example of malignant myoepithelioma of the vulva, which has not been hitherto described. We discuss the differential diagnosis and briefly review the literature. methods AND RESULTS: The lesion was found in an 81-year-old woman as an indolent 40 mm tumour. The neoplastic cells showed a myoid, spindled, epithelioid and plasmacytoid phenotype. Hyalinization of extracellular material and myxoid changes were present. There was a partly solid and microcystic pattern and a tight cohesiveness of cells was lacking. The circumscribed multinodular tumour somewhat resembled an extrarenal rhabdoid tumour, having large tumour cells with prominent nucleoli and large amounts of acidophilic cytoplasm. Immunohistochemically, the tumour cells were immunoreactive for cytokeratin, vimentin, muscle-specific actin, alpha-smooth muscle actin, and S100 protein, but not for desmin, epithelial membrane antigen, factor viii-related antigen, CD34 and CD31. CONCLUSIONS: The histological and cytomorphological appearance of the tumour well as the immunohistochemical findings suggest the diagnosis of malignant myoepithelioma, possibly derived from minor vestibulary glands or ectopic breast tissue. Differential diagnoses are, in particular, extrarenal rhabdoid tumour and 'proximal type' epithelioid sarcoma. Differentiation is important, because the tumours show a different behaviour and prognosis.- - - - - - - - - - ranking = 0.5keywords = behaviour (Clic here for more details about this article) |