Gastrointestinal autonomic nerve tumor of the rectum - A rare case report

Abstract

Gastrointestinal stromal tumour (GIST) is the most common mesenchymal, or nonepithelial, neoplasm of the gastrointestinal (GI) tract. Gastrointestinal autonomic nerve tumour (GANT) is a subset of GIST and a very rare mesenchymal tumour with neuronal differentiation. We report a 33-year-old gentleman presented with a chief complaint of perianal pain, itching, and mucus discharge per rectum for the past 4 months. There was no history of bleeding per rectum/loss of weight/loss of appetite. On digital rectal examination: Hard fixed growth at 2–8 O' clock approximately 5 cm from the anal verge and proximal extent could not be felt. Magnetic resonance imaging pelvis revealed a mass lesion involving the inferior two third of the rectum and anal canal predominantly the posterior and lateral walls. Contrast-enhanced computed tomography abdomen and pelvis revealed a heterogeneously enhancing mass involving the lower rectum (involving posterior and both lateral walls) and also circumferentially involving the entire length of anal canal with severe luminal narrowing. Upper border 10 cm from anal verge. Multiple enlarged perirectal/ para-aortic/presacral lymph nodes. Colonoscopy demonstrated an ulceroproliferative growth of 7 cm from anal verge, extending from 2 to 7 o' clock position. Examination was carried out under anaesthesia and biopsy was also done. Biopsy with Immunohistochemical analysis suggestive of GI autonomic nervous system tumour. Treatment Palliative end colostomy was done in view of large locally advanced infiltrating growth involving the lower rectum and anal canal and coccyx.