A Case of Schwannoma of the Sigmoid Colon

Abstract

An 81-year-old woman presented with abdominal pain and bloody stool. She was diagnosed with ischemic colitis and referred to our hospital. Abdominal computed tomography showed a 35-mm tumor in the sigmoid colon. The tumor was not detected on colonoscopy, but fluorodeoxyglucose-positron emission tomography (FDG-PET) showed enhanced uptake. Because the possibility of malignant disease could not be ruled out, sigmoidectomy was performed. The histopathologic and immunohistochemical diagnosis was schwannoma of the colon, which is rare. Preoperative diagnosis is difficult for this type of submucosal tumor. Schwannoma presents with high uptake on FDG-PET scanning, but it is not malignant. Therefore, it is necessary to carefully consider the treatment strategy.