Cytoskeletal heterogeneity of an epithelioid sarcoma with expression of vimentin, cytokeratins, and neurofilaments.

We studied an unusual sarcoma with morphologic features diagnostic of epithelioid sarcoma by conventional light microscopy, transmission electron microscopy, and immunohistochemistry. The primary tumor, which was located in the deep soft tissues of the buttock of a 32-year-old woman, and its metastases to lymph nodes, liver, and lung were available for investigation. The histomorphological and ultrastructural appearance of the primary tumor and its metastatic deposits were typical of epithelioid sarcoma. Immunohistochemistry revealed a strong and uniform reactivity for vimentin in both the primary tumor and its metastases. In contrast, a marked cytoskeletal heterogeneity became evident for cytokeratins and neurofilaments, which were observed exclusively in lymph node metastasis. To our knowledge, the observation of neurofilaments in epithelioid sarcoma has not previously been reported.