Carcinoid and neuroendocrine tumors of the colon and rectum.

Carcinoid and neuroendocrine tumors of the colon and rectum arise from the amine precursor uptake and decarboxylation (APUD) cells of the intestine. Carcinoid tumors are most commonly found in the gastrointestinal tract and are located in decreasing order of frequency in appendix, ileum, rectum, stomach, and colon. The vast majority of lesions are asymptomatic and are found incidentally during endoscopy. The management of these lesions depends upon the size of the lesion, involvement of the muscularis, location, and presence of metastatic disease. Small lesions (1 cm) can often be treated locally, either endoscopically or transanally. However, larger lesions (> 2 cm) require a formal oncologic resection. Adjuvant therapy is indicated only for metastatic disease, and admirable advances have been made in the realm of chemotherapy for reduction of disease and palliation of the symptoms of carcinoid syndrome. In this article, we discuss the nature of these interesting and uncommon tumors, clinical presentation, treatment options, and prognosis.