Today at MHH morning report a case of pulmonary carcinoid was presented.
For quick board-type "pointers, " here are some key Learning Points about carcinoid in general:
Most commonly affected areas are the GI Tract (especially Stomach, Small Intestine, appendix and rectal) and the Bronchial location. Other sites involved, although rare, include ovaries, pancreas, gallbladder and testes
For Pulmonary Lesions:
1) Local Effect - Obstruction, persistant pneumonia, atelectasis, bleeding from irritation,
2) Systemic -
-About 15% get the "carcinoid syndrome": Diarrhea, Flushing, Tachycardia,
Bronchoconstriction, hemodynamic instability - all from excess serotonin. Since these are
excreted directly into the systemic circulation, patients do NOT have to have metastatic
disease to the liver to get this syndrome.
-The flushing usually is on the upper torso and face and lasts 10-30 minutes
-Episodes of Diarrhea can number even >15x a day
-Patients can get tricuspid and pulmonary disease (esp stenosis) due to fibrosis caused by
serotonin. The other valves are not affected because the lungs degrade serotonin
-Patients can also get a secondary pellagra from niacin deficiency
-Wheezing and asthma are present in >25% of patients
-About 1% get Cushings Syndrome from ectopic ACTH production
For GI Lesions:
1) Local - Anemia, abdominal pain, weight loss
2) Systemic - The carcinoid syndrome as above can occur, but lesions from the GI tract have
to metastasize to the liver before getting this constellation of findings.
Diagnosis of Carcinoid:
1) Urine 5-Hydroxyindoleacetic acid (5-HIAA) - A metabolite of serotonin. Elevated in 75% of patients.The patient has to be on a strict diet, as certain foods (like caffeine, wine, cheese) can falsely elevate the results. In addition, medications like INH and Acetaminophen can also elevate the results.
2) Serum Chromogranin A is elevated in 90% of patients, but only suggests that a neuroendocrine tumor is present
3) Radionucleotide scan with Indium-111 scan has a high sensitivity and specificity to help localize the lesion
4) For Pulmonary Tumors - Imaging will show a lesion in greater than 75% of patients - Then need Biopsy. Same for GI Tract - can image with colonoscopy (rectal lesions) or CT to better visualize other locations. Then biopsy
Subcutaneous Octreotide helps relieve the symptoms of the carcinoid syndrome in all tumor types.
Pulmonary Carcinoid is usually treated with surgery +/- Chemotherapy with Streptozotocin/5-FU
GI Carcinoids are also treated with surgery, and various chemotherapy regimens are used