Carcinoid Tumors Flashcards
What is a carcinoid tumor?
Tumor arising from neuroendocrine cells (Kulchitsky cells).
Secretes serotonin.
Why is a carcinoid tumor called “carcinoid”?
A carcinoid resembles a carcinoma but is clinically and histologically less aggressive than most GI carcinomas
How can you remember that Kulchitsky cells are found in carcinoid tumors?
KUL CAR
What are the common sites for carcinoid tumors?
AIR:
Appendix, Ileum, Rectum
Also bronchus, jejunum, stomach, duodenum, colon, ovary, testicle, pancreas, thymus
What are the signs and symptoms of a carcinoid tumor?
Depends on the location (most cases are asymptomatic).
SBO, abdominal pain, bleeding, weight loss, diaphoresis, pellagra skin changes, intussusception, carcinoid syndrome, wheezing
Why SBO with carcinoid?
Severe mesenteric fibrosis
What are the pellagra-like symptoms of a carcinoid tumor?
- Dermatitis
- Diarrhea
- Dementia
What causes pellagra in carcinoid patients?
Decreased niacin production
What is carcinoid syndrome?
Syndrome of symptoms caused by release of substances from a carcinoid tumor
What are the symptoms of carcinoid syndrome?
B FDR:
Bronchospasm, Flushing (skin), Diarrhea, Right-sided heart failure (from valve failure)
Why does right-sided heart failure develop but not left-sided heart failure in carcinoid syndrome?
Lungs act as a filter, thus the left heart doesn’t see all the vasoactive compounds
What is the incidence of carcinoid syndrome in patients with a carcinoid tumor?
10%
What released substances cause carcinoid syndrome?
Serotonin and vasoactive peptides
What is the medical treatment for carcinoid syndrome?
Octreotide IV
What is the medical treatment of diarrhea alone in carcinoid syndrome?
Odansetron (Zofran)
How does the liver prevent carcinoid syndrome?
By degradation of serotonin and the other vasoactive peptides when the tumor drains into the portal vein
Why does carcinoid syndrome occur in some tumors and not in others?
Occurs when venous drainage from the tumor gains access to the systemic circulation by avoiding hepatic degradation of the vasoactive substances
What tumors can produce carcinoid syndrome?
Liver metastases; retroperitoneal disease draining into paravertebral veins; primary tumor outside of GI tract, portal venous drainage, or both
What does the liver break down serotonin into?
5-HIAA
What percentage of patients with a carcinoid have an elevated urine 5-HIAA level?
50%
What are the associated diagnostic lab findings with carcinoid tumor?
Elevated urine 5-HIAA as well as elevated urine and blood serotonin levels
How do you remember 5-HIAA for carcinoid?
5-HIGH CAR pile up
What stimulation test can often elevate serotonin levels and cause symptoms of carcinoid syndrome?
Pentagastrin stimulation
How do you localize a GI carcinoid?
Barium enema; upper GI series with small bowel follow-through; colonoscopy; enteroscopy; enteroclysis; EGD; radiology tests
What are the special radiologic (scintigraphy) localization tests for carcinoid tumors?
I-MIBG; In-octreotide; PET scan utilizing C-labeled HTP
What is the surgical treatment for carcinoid tumor?
Excision of the primary tumor and single or feasible metastasis in the liver; chemotherapy for advanced disease
What is the medical treatment for carcinoid tumor?
Palliation of the carcinoid syndrome (e.g. serotonin antagonists, somatostatin analog)
How effective is octreotide in treating carcinoid syndrome?
It relieves diarrhea and flushing in more than 85% of cases and may shrink tumor in 10-20%
What is a common anti-serotonin drug?
Cyproheptadine
What is the overall prognosis for carcinoid tumor?
66% alive at 5 years
What is the prognosis of patients with liver metastasis or carcinoid syndrome secondary to carcinoid tumor?
50% at 3 years
What does a carcinoid tumor look like?
Usually intramural bowel mass.
Appears as yellowish tumor upon incision.
For appendiceal carcinoid, when is a right hemicolectomy indicated vs. an appendectomy?
If the tumor is > 1.5 cm, right hemicolectomy is indicated.
If there are no signs of serosal or cecal involvement and tumor is < 1.5 cm, appendectomy should be performed.
Which primary site of carcinoid tumor has the highest rate of metastasis?
Ileal primary tumor
Can a carcinoid tumor be confirmed malignant by looking at the histology?
No, metastasis must be present to diagnose malignancy
What is the correlation between carcinoid tumor size and malignancy potential?
Vast majority of tumors < 2 cm are benign.
In tumors > 2 cm, malignancy potential is significant.
What treatments might you use for the patient with unresectable liver metastasis that is refractory to medical treatment?
Chemoembolization or radiofrequency ablation
What are the overall survival rates for carcinoid tumors at 5 years? 10 years?
70%; 50%
What are the side effects of colorectal carcinoid?
Most common side effect is rectal bleeding +/- vague abdominal pain or discomfort
