Colonic Schwannoma: A Case Study and Literature Review of a Rare Entity and Diagnostic Dilemma

An asymptomatic 73-year-old woman was found to have a submucosal mass in the descending colon on routine colonoscopy. A CT scan revealed a 31 × 28 × 31 mm lesion in the same location. Previous biopsy proved to be nondiagnostic, and the patient underwent a laparoscopic descending colon resection. Histologic evaluation of the tumor revealed a low grade spindle cell neoplasm with strong, diffuse positivity for S-100 protein by immunohistochemistry, leading to the diagnosis of schwannoma. A review of the literature revealed intestinal schwannoma to be a rare disease entity, with only about 50 cases previously reported.