Solitary malignant schwannoma of the pancreas: report of a case and ultrastructural examination.

Primary malignant schwannoma of the pancreas is rare. The reported patient, a 40-year-old white female, presented with obstructive jaundice and a large palpable mass in the upper abdomen. A Whipple procedure was performed. Electron microscopic examination of the tumor established the Schwann cell origin of the neoplasm by demonstrating basement membranes, junctional complexes, and interdigitating cytoplasmic extensions infested with basal lamina, dense neurosecretory-like granules, and axon-like structures. The inadequacy of light microscopic examination alone for establishing the diagnosis with certainty is discussed. Review of the literature revealed only one case of a malignant schwannoma of the pancreas that was not resected. This is the first report confirmed by ultrastructural examination.