Malignant peripheral nerve sheath tumor of the skin: a superficial form of this tumor

Abstract

A case of malignant peripheral nerve sheath tumor (MPNST) of the skin, which is a superficial form of this type of tumor, is described. Although our patient did not present the usual diagnostic criteria for MPNST, the clinicopathologic findings for both the initial and recurrent tumors were compatible with those of the ordinary type of this tumor and not with those of neurotropic melanoma or cellular schwannoma. The recurrent tumor presented progression compared to the low grade malignancy in the original tumor. Perhaps because of the superficial location of the tumor our patient showed an unexpected favorable outcome in spite of repeated recurrences. Reports indicate that, of the superficial forms, the ordinary type is still less frequently encountered than the epithelioid type. We also discuss the differentiation between MPNST of the skin and neurotropic melanoma.