1/4. Solitary neurofibroma of the oral mucosa: a previously undescribed variant of neurofibroma.We report a distinct morphologic type of neurofibroma, lipomatous neurofibroma, arising in the oral mucosa, which has not been described previously in the literature. A 25-year-old female patient presented with a solitary mucosal mass on the palatal gingiva. Although the limited biopsy material was diagnosed as a spindle cell lipoma, characteristic light microscopic neurofibromatous areas, intricately admixed with mature fat, were found in the entire resection specimen. Immunohistochemically, many of the spindle cells were positive, either diffusely or focally, for common neural markers, with patchy staining for CD34 and epithelial membrane antigen. S-100 protein was also positive in adipocytes. Ultrastructural examination confirmed the diagnosis of neurofibroma and suggested an intimate relationship between neoplastic neural cells and adipocytes.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/4. A case of perineurioma with prominent myxoid changes.A perineurioma with prominent myxoid changes is presented. The patient, a 41 year-old woman, presented with a small skin nodule on her back. light microscopy revealed subtle cellular whorls within a myxoid background. immunohistochemistry showed epithelial membrane antigen positivity. In contrast, S-100 protein, common leukocyte antigen, vimentin and AE1-AE3 cytokeratin were negative.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
3/4. Comparative ultrastructural and immunohistochemical study of perineurioma and neurofibroma of the oral mucosa.In the course of assessing the cellular composition of intraoral neurofibroma (NF), we encountered a unique gingival tumor of putative perineurial (PN) origin. The lesion showed the ordinary light microscopic NF pattern, but the ultrastructural features of well-differentiated PN cells as well as an epithelial membrane antigen (EMA)-positive, S-100 protein-negative immunoprofile confirmed the diagnosis of soft tissue perineurioma (STP). In our small series of NF, there were three ultrastructural subtypes: Type I (common Schwann cell type), Type II (NF with a high content of PN cells) and Type III (predominantly fibroblastic NF), although inhomogeneous and overlapping assembly of cellular elements. A significant number of tumor cells in Type II showed the substantial reactivity for EMA, whereas many CD34-positive cells were noted in Type III. The present results confirm previous findings that PN lineage is an important constituent in the formation of NF and reinforce the value of electron microscopy in the diagnosis of peripheral nerve sheath tumors.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/4. Mucosal neuromas and plexiform neurofibromas: an immunocytochemical study.Mucosal neuromas (MN), a component of multiple endocrine neoplasia (MEN) type IIb, may be confused histologically with plexiform neurofibromas (PN), a component of neurofibromatosis. The ability to distinguish between these two markers for different genetic diseases is crucial, as the risk of development of medullary thyroid carcinoma and pheochromocytoma in affected patients with MEN IIb is great. We studied two cases each of MN and PN by immunocytochemistry (IC). Epithelial membrane antigen (EMA) proved to be the most useful marker. MN consisted of bundles of disorganized and tortuous nerve fibers surrounded by a thickened perineurium that expressed the cellular phenotype EMA( ), S-100(-). PN consisted of enlarged nerve fascicles with a loose myxoid stroma and was EMA negative. Thus, IC highlighted the differing pattern of growth and histogenesis of the proliferating cells in the two lesions and is likely to be especially useful in those lesions with atypical histology.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |