The purely epithelioid malignant peripheral nerve sheath tumor(MPNST) is a rare form of MPNST, first described by McCormack et al. in 1954. This tumor type differs from ordinary epithelioid MPNST because of absence of spindle cell components. The patient was 25-year-old woman with palpable bean-sized subcutaneous mass on the right upper arm for 8 months which enlarged gradually. On physical examinations, we could not find a evidence of lymphadenopathy or von Reklinghausen's disease. Microscopically the tumor showed well circumscribed encapsulated nodular pattern composed of epithelioid cells. The cells were plump round or polygonal cells which had vesicular nuclei and prominent nucleoli with abundant eosinophilic and some clear cytoplasms. Immunohistochemical study showed the cells being positive for S-100 protein and neuron specific enolase and negative for HMB-45, cytokeratin and vimentin. We report a case of purely epithelioid malignant peripheral nerve sheath tumor which is located superficially without evidence of von Recklinghaunsen's disease or associated peripheral nerve. (Korean J Dermatol 2000;38(4)：518~521)