Origin: Neuroendocrine cells
Location: Lungs, Bronchi, Trachea, Gastrointestinal tract
Synthesize: Biogenic amines (mainly serotonin which is metabolied to 5-HIAA)
5 Manifestations
Mnemonic: 5-HIAAS
1. Heart disease (2/3 patients)
- Right sided valvular heart lesions (due to factors secreted into hepatic vein by liver metastases)
- Tricuspid regurgitation
- Tricuspid stenosis
- Pulmonary stenosis (less common)
- Left sided heart disease (infrequent): 10%
- Hypotension
2. Intestinal manifestations
- Gastrointestinal bleeding
- Obstruction
- Watery diarrhea unresponsive to fasting
3. Airway obstruction
- Localized wheezing +/- hemoptysis
4. Asthma
- Significant diffuse wheezing
5. Skin manifestations
- Intense cutaneous flushing
- Necrolytic erythema
Alternative mnemonic: CARCinoid
- Cutaneous flushing
- Asthmatic wheezing
- Right sided valvular heart lesions
- Cramping and diarrhea
Rule of 1/3
- 1/3 of carcinoid tumors metastasize.
- 1/3 of carcinoid tumors present with 2nd malignancy.
- 1/3 of carcinoid tumors are multiple.
Surgery for appendiceal carcinoid tumor
- <2 cm: Simple appendectomy
- >2 cm or mesoappendix invasion: Hemicolectomy
Medical therapy
- Somatostatin analogue: Octreotide
- Tryptophan hydroxylase inhibitor: Telotristat