Plexiform schwannoma of the small intestine: report of a case.

Plexiform schwannoma is a benign peripheral nerve sheath tumor composed exclusively of schwann cells arranged in a plexiform pattern. Most plexiform schwannomas are skin tumors and there has been only one case report of this tumor originating in the colon. We describe herein the first known case of plexiform schwannoma of the small intestine occurring without any relationship to schwannomatosis or neurofibromatosis. A 57-year-old man presented with a short history of abdominal pain, vomiting, and bloody stool after each meal. Jejunography demonstrated multiple nodular tumors in the small intestine. We resected the small intestine laparoscopically. The tumors consisted of multiple white nodules in the submucosal and subserosal layers. Microscopic examination revealed that each tumor was composed mainly of Antony A tissue, compatible with conventional schwannoma. Immunohistochemically, the tumors were positive for S-100, vimentin, and neuron-specific enolase, and negative for HHF35, Alpha-SMA, and c-kit. No evidence of recurrence has been found in 38 months of follow-up.