[A case of mucosal Schwann cell hamartoma].

A 40-year-old man was referred to our hospital because of a positive fecal occult blood test. Colonoscopy revealed many small whitish nodules in the mucosa of the sigmoid colon. Specimens endoscopically resected from the lesions revealed spindle cell proliferation in the lamina propria. Immunohistochemical study revealed strong and diffuse positivity for S-100 protein. Results of staining for neurofilament protein and epithelial membrane antigen were negative. The neurogenic tumors were diagnosed as mucosal Schwann cell hamartoma. No clinical features of multiple endocrine neoplasia type 2B or neurofibromatosis type 1 were found in the present case.