Classification and Locoregional Treatment of Rectal Neuroendocrine Tumors.

A 43-year-old male presented to his primary care physician's office with a complaint of painless rectal bleeding with a concomitant weight loss of 10-15 pounds and intermittent abdominal pain. Endoscopic evaluation was remarkable for a 5 mm rectal polyp roughly 10 cm from the anal verge. Resection was performed and the pathology was consistent with a low-grade neuroendocrine/carcinoid tumor. Immunostaining for synaptophysin, chromogranin, CD56, and CAM5.2 were positive while staining for CK20 was negative. Given the absence of metastasis on radiographic and endoscopic evaluation, the patient was managed conservatively thereafter with observation. Despite having an indolent clinical course, resection is recommended for all rectal neuroendocrine tumors. Locoregional endoscopic resection versus radical resection can be used for adequate tissue removal depending on the characteristics of the tumor and the degree of invasion.