A Large Pedunculated Rectal Carcinoid Tumor Resected by Endoscopic Snare Polypectomy

Abstract

A 53 y/o asymptomatic black female with a history of HTN underwent a routine screening colonoscopy which revealed a 18mm pedunculated rectal polyp as well as a 10mm pedunculated transverse colon polyp. Both were removed by snare cautery. The rectal polyp was grossly atypical. It was pale, firm and nodular with irregular borders on a wide stalk. Pathology reported a rectal carcinoid tumor and a transverse colon tubular adenoma and. An endoscopic rectal ultrasound was performed three weeks later which revealed no invasion of the submucosa. Multiple jumbo biopsies were obtained from the polypectomy site all were negative for any residual carcinoid tumor tissue. Computed tomography of the chest, abdomen and pelvis were negative for metastasis. Discussion: Carcinoid tumors are derived from the neuroendocrine system. They have the capbility of secreting an array of biologically active agents. The incidence of carcinoid tumors has been estimated to be 8.4 per 100,000. 74% of carcinoid tumors are located in the gastrointestinal tract, the ileum, appendix and the rectum are the most common GI sites. The Bronchopulmonary system is responsible for the majority of the other sites. Grossly they are usually submucosal. They are usually yellow/tan or pale/gray secondary to a high lipid content, as well as firm and rubbery. Histologically they appear as nests, cords or rossettes of uniform round cells with rare mitotic figures. Immunohistochemically, they may be differentiated from other neuroendocrine tumors with chromogranins A, B, C, synaptophysin and enolase stains. They are best visualized endoscopicaly using EUS and by Somatostatin scintography, PET scans and CT scans. Tumors less than 1cm < 2% chance of mets, 1–1.9cm 10–15%, >2cm 60–80%. The overall survival rate of rectal carcinoid tumors is 72%. Their prognosis and treatment depend on a variety of factors including: location, size, degree of invasion and possibly by whether they are sessile or pedunculated. Pedunculated rectal carcinoid tumors are extremely rare. This may be the tenth reported case in medical literature. There have been recommendations regarding endoscpopic resection of flat, sessile rectal carcinoid tumors, however in our case of a pedunculated carcinoid tumor, more studies are needed to determine the prognosis and the most appropriate treatment.