Gastrointestinal Pathology- Clinicopathologic Correlation in Mucosal Biopsy

Case #2 (question #3):

    A 35 year-old gentleman with a history of familial adenomatous polyposis (FAP), status post colectomy and now with duodenal polyps. Representative images are illustrated below:

Click on thumbnails to see full sized pictures.

Question No. 3. The Answer is: (C) It is more commonly found in the rectum than other parts of the colon..

Discussion: The photomicrographs show nests of cells with round and uniform nuclei, morphologically consistent with a low-grade neuroendocrine neoplasm (carcinoid tumor).  Carcinoid tumors of the rectum are more common than those of other parts of the colon. Colonic carcinoid tumors are most commonly present in the seventh decade.  The most common presentation is with symptoms of abdominal pain and weight loss.  Less than 5% of patients present with the carcinoid syndrome.  They commonly appear as submucosal nodules, while sometimes are polypoid. Rectal carcinoids generally have a good prognosis, showing a 5-year survival rate of 72% to 89%.  The distribution in colon with relative frequencies are as follows: rectum (54%), cecum (20%), sigmoid colon (7.5%), rectosigmoid colon (5.5%), and ascending colon (5%).

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