title: Schwannoma of the duodenum causing melena.
abstract: A rare case of duodenal schwannoma is reported. A 69-year-old man was admitted for evaluation of melena. Endoscopy and hypotonic duodenography showed a submucosal tumor in the third part of the duodenum. Biopsy findings were suggestive of leiomyosarcoma, therefore pancreatoduodenectomy was performed. Hematoxylin-eosin staining of the resected specimen showed interlacing bundles of spindle-shaped cells with palisading nuclei. Immunohistochemical staining showed positivity for S-100 protein and neuron-specific enolase, but desmin was negative, thus a diagnosis of schwannoma was made. Schwannoma is often difficult to distinguish from leiomyogenic tumors by standard staining, but immunohistochemical staining proved useful in this case.
authors: First Department of Internal Medicine, Nagoya City University Medical School.
authors: K
authors: K
authors: Seno
authors: M
authors: M
authors: Itoh
authors: K
authors: K
authors: Endoh
authors: T
authors: T
authors: Joh
authors: Y
authors: Y
authors: Yokoyama
authors: T
authors: T
authors: Takeuchi
authors: T
authors: T
authors: Nakamura
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D004379:Duodenal Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D004386:Duodenum / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007890:Leiomyosarcoma / Q000175:diagnosis; D008297:Male; D008551:Melena / Q000209:etiology*; D009442:Neurilemmoma / Q000150:complications* / Q000175:diagnosis / Q000601:surgery