When a polyp is not a polyp: incidental finding of a sigmoid schwannoma at first colonoscopic screening.

Schwannomas, peripheral nerve sheath tumours arising from Schwann cells, are often associated with inherited disorders such as neurofibromatosis. Gastrointestinal schwannomas, while rare, have been reported in those without personal or family history of neurofibromatosis. Diagnoses of these lesions, however, typically follow evaluations prompted by symptomatic presentations associated with abdominal pain, rectal bleeding, change in bowel habits or positive results on faecal occult blood tests performed for colorectal cancer screening. Further, management of these predominantly benign lesions commonly incorporates surgical resection. We present the case of a sigmoid schwannoma found in an asymptomatic individual on first screening colonoscopy and treated with complete endoscopic polypectomy with anticipated surveillance colonoscopy. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.