Abstrakt
We report a case of a 58-year-old who woman presented with a solitary slowly growing subcutaneous nodule covered by normally appearing skin on her left groin. Microscopically, the lesion was well circumscribed but unencapsulated, and showed biphasic cellular differentiation.
One cell population was presented by small rounded (epithelioid) cells arranged singly, in small aggregates or short cords, whereas the second one was composed of cells with slender nuclei and delicate elongated bipolar cytoplasmic processes. On immunohistochemistry, the epithelioid component showed positive reaction for S-100 protein and negative for epithelial membrane ntigen (EMA), thus compatible with schwannian differentiation and resembling epithelioid schwannoma.
The other component showed reverse immunophenotype being S-100 protein negative and EMA ositive, thus corresponding to perineuriomatous differentiation. The linicopathologic nd immunohistochemical features of the lesion were ompatible with hybrid epithelioid schwannoma/perineurioma, a rare orphological variant of peripheral nerve sheath tumors.