Usually associated with excessive secretion of serotonin

• A small tumor (benign or malignant) arising from the mucosa of the gastrointestinal tract

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
carcinoid \carcinoid\ [From Gr. karki`nos, a crab + -oid.] n. A small tumor (benign or malignant) arising from the mucosa of the gastrointestinal tract; it is usually associated with excessive secretion of serotonin.

Wiktionary Word definitions in Wiktionary
n. (context medicine English) A form of slow-growing tumour originating in the neuroendocrine system.

Wikipedia Word definitions in Wikipedia
Carcinoid (also carcinoid tumor ) is a slow-growing type of neuroendocrine tumor originating in the cells of the neuroendocrine system . In some cases, metastasis may occur. Carcinoid tumors of the midgut ( jejunum , ileum , appendix , and cecum ) are associated ...

WordNet Word definitions in WordNet
n. a small tumor (benign or malignant) arising from the mucosa of the gastrointestinal tract; usually associated with excessive secretion of serotonin