Miscellaneous Neoplasms.

Carcinoid tumors originate from enterochromaffin cells, part of the diffuse endocrine system. Thus, they are considered to belong in the neuroendocrine group of tumors.1 They are a confusing group of tumors with a wide range of behavior. Carcinoid tumors may be located in any of a number of locations within and outside the gastrointestinal (GI) tract, may be single or multiple, may produce a wide array of biochemical products, may produce symptoms from the biochemical products or the tumor itself, and exhibit varying degrees of biochemical and aggressive behavior relative to their location. This section will focus on carcinoid tumors of the small bowel, appendix, colon, and rectum. [ABSTRACT FROM AUTHOR]