[A case of rectal schwannoma presenting with hematochezia].

Rectal schwannoma is a rare mesenchymal tumor originating from Schwann's cell. We experienced a 61- year-old female patient who complained of blood tinged and narrow calibered stool for several years, and found a 4 cm sized submucosal tumor with a central ulcer on the rectal wall during colonoscopy. She underwent transanal excision. Microscopically, the tumor was composed of fasciculating bundles of spindle cells with benign nuclear atypia and peripheral lymphoid cell cuffing. Tumor cells showed a diffuse strong immunoreactivity to S-100 protein, but not stain for CD 34, desmin and smooth muscle actin. This is the first case report of rectal schwannoma in Korea.