Carcinoid Tumors (Mid-Gut)
DEFINITION:
Carcinoids arise from enterochromaffin cells of the gastrointestinal tract See also Bowel- GI Endocrine Tumors (Chapter 2.16)
The term enterochromaffin refers to the ability to stain with potassium chromate (chromaffin), a feature of cells that contain serotonin
Classification includes tumors of the:
Foregut (including the lungs, bronchi, stomach, duodenum, pancreas) See also Esophagus/Gastric-Gastropathy (Chapter 1.13)
Midgut (including the small intestine, appendix, and proximal colon)
Hindgut (including the distal colon, rectum, and genitourinary tract): rarely produce serotonin
EPIDEMIOLOGY:
Carcinoid tumors are rare, but are the most common gastrointestinal neuroendocrine tumors
Incidence: Caucasian ♂/♀: 2.5/2.5 per 100,000; African American ♂/♀: 4.5/4.0 per 100,000
Age peak (bimodal): 15-25 and 65-75; Female predominance <50 y/o, Male predominance >50 y/o
PATHOPHYSIOLOGY:
WHO classification (2000):
Well-differentiated neuroendocrine tumor; Benign behavior or uncertain malignant potential; AKA: Carcinoid
Well-differentiated neuroendocrine carcinoma; Low grade malignancy; AKA: Malignant carcinoid
Poorly-differentiated neuroendocrine carcinoma; High grade malignancy; AKA: Malignant carcinoid
Majority of carcinoids (55%) occur in the GI tract:Related posts:
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