Primitive neuroectodermal tumor arising in the ulnar nerve. A case report.

Malignant peripheral nerve tumors are rare. A neuroectodermal tumor arose in a 59-year-old man from the ulnar nerve. Typically, the tumor reproduces some of the appearances of cells of the primitive central nervous system. The possibility that a primary tumor of the sympathetic nervous system, especially of the adrenal glands, should be considered in the differential diagnosis. The tumor may arise from a major peripheral nerve and show features of growth patterns of the embryonic central nervous system. Blood stream spread is not uncommon; awareness of this proclivity makes early diagnosis mandatory.