Kikuchi A, Akiyama M, Han-Yaku H, Shimizu H, Naka W, Nishikawa T
Department of Dermatology, Keio University School of Medicine, Tokyo, Japan.
Am J Dermatopathol. 1993 Feb;15(1):15-9. doi: 10.1097/00000372-199302000-00003.
We describe two cases of malignant schwannoma in the skin that did not originate from a nerve trunk and was not associated with neurofibromatosis. Light microscopy showed that both tumors were composed predominantly of atypical spindle-shaped cells. Immunohistochemical analysis was performed with various monoclonal antibodies against mesenchymal determinants. In both patients, tumor cells were positive for S-100 alpha and S-100 beta, neuron-specific enolase, vimentin, neurofilament protein, and myelin basic protein, and negative for HMB-45, glial fibrillary acidic protein, epithelial membrane antigen, and desmin. Electron microscopy revealed that the tumor cells possessed indented nuclei with an electron-lucent cytoplasm. Immunoelectron microscopy showed diffuse fine granular staining for S-100 alpha, not detectable in normal Schwann cells, in the cytoplasm of the tumor cells.
