S4027 Unmasking a Rare Neoplasm: Rectal Perineurioma

Introduction: Colonic perineuriomas are uncommon benign mucosal proliferations of mesenchymal cells expressing perineural markers. We are presenting a case of incidental diagnosis of rectal perineurioma during surveillance colonoscopy. Case Description/Methods: 55-year-old woman without any significant past medical history, presented for surveillance colonoscopy due to prior history of colon adenomas. No family history of colon cancer. No history of nausea, vomiting, abdominal pain, melena, hematochezia, change in bowel habits, and unintentional weight loss. On examination, patient was comfortable, abdomen was soft, non-tender, without organomegaly or ascites. During the colonoscopy, 4 2-6 mm sessile polyps were removed from the rectosigmoid using cold biopsy forceps and cold snare. Microscopic examination of the polyps demonstrated bland spindle cells in the lamina propria and immunostains confirmed the diagnosis of perineurioma. Discussion: Colonic perineurioma is a relatively rare type of benign tumor found in the gastrointestinal tract. The mean age at diagnosis is 60 years, and there is a slight woman predominance. Three-fourth of the colonic perineuriomas are found in the sigmoid colon or rectum. Histologically, they are composed of spindle cells that fill the lamina propria. Given the benign nature of perineurioma, endoscopic removal is not indicated in asymptomatic patients.