A CASE OF SIGMOID COLON SCHWANNOMA

—A Case Report—

Abstract

Although schwannomas are common in the neck, brain, and extremities, they are relatively rare in the gastrointestinal tract and particularly rare in the large intestine. We here present a rare case of schwannoma arising from the sigmoid colon. A 73-year-old woman presented to nearby clinic with abnormalities on colorectal cancer screening, and an elevated lesion, suggestive of a submucosal tumor, was observed in the sigmoid colon by colonoscopy. Although the endoscopic biopsy results showed normal mucosa, laparoscopy assisted partial resection of the sigmoid colon was performed in order to rule out gastro intestinal stromal tumor (GIST). Pathological examination of the resected specimen demonstrated spindle cells in a submucosal lesion. Immunohistochemical staining was strongly positive for S-100 protein, and negative for c-kit and smooth muscle actin; Ki-67 showed a low rate positive. Thus, the diagnosis of schwannoma in the sigmoid colon was confirmed.