Carcinoid Tumors, C46 P301-305 Flashcards
What is a carcinoid tumor?
P301
Tumor arising from neuroendocrine cells
(APUDomas), a.k.a. Kulchitsky cells;
basically, a tumor that secretes serotonin
Why is it called “carcinoid”?
P301
Suffix “-oid” means “resembling”; thus,
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?
P301
Think: “COOL CAR” or KULchitsky
CARcinoid
What is the incidence?
P301
Between 0.2% and 1.0% and about 25%
of all small bowel tumors
What are the common sites
of occurrence?
P301
“AIR”: 1. Appendix (most common) 2. Ileum 3. Rectum 4. Bronchus Other sites: jejunum, stomach, duodenum, colon, ovary, testicle, pancreas, thymus
What are the signs/
symptoms?
P301
Depends on location; most cases are asymptomatic; also SBO, abdominal pain, bleeding, weight loss, diaphoresis, pellagra skin changes, intussusception, carcinoid syndrome, wheezing
Why SBO with carcinoid?
P301
Classically = severe mesenteric fibrosis
What are the pellagra-like
symptoms?
P302
Think “3-D”:
- Dermatitis
- Diarrhea
- Dementia
What causes pellagra in
carcinoid patients?
P302
Decreased niacin production
What is carcinoid syndrome?
P302
Syndrome of symptoms caused by release
of substances from a carcinoid tumor
What are the symptoms of
carcinoid syndrome?
P302
Remember the acronym “B FDR”:
Bronchospasm
Flushing (skin) Diarrhea Right-sided heart failure (from valve failure)
What is a complete memory
aid for carcinoid?
P302 (picture)
Think: B FDR = CARcinoid, or “Be FDR
in a cool CAR” (COOL= KULchitsky cells)
Why does right-sided heart
failure develop but not
left-sided heart failure?
P302
Lungs act as a filter (just like the liver);
thus, the left heart doesn’t see all the
vasoactive compounds
What is the incidence of carcinoid SYNDROME in patients who have a carcinoid TUMOR? P302
≈10%
What released substances
cause carcinoid syndrome?
P302
Serotonin and vasoactive peptides
What is the medical treatment
for carcinoid syndrome?
P302
Octreotide IV
What is the medical
treatment of diarrhea alone?
P302
Odansetron (Zofran®)—serotonin
antagonist
How does the liver prevent
carcinoid syndrome?
P303
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?
P303
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?
P303
Liver metastases
Retroperitoneal disease draining into
paravertebral veins
Primary tumor outside the GI tract,
portal venous drainage (e.g., ovary,
testicular, bronchus), or bothWhat does the liver break
down serotonin into?
P303
5-hydroxyindoleacetic acid (5-HIAA)
What percentage of patients
with a carcinoid have an
elevated urine 5-HIAA level?
P303
50%
What are the associated
diagnostic lab findings?
P303
Elevated urine 5-HIAA as well as
elevated urine and blood serotonin
levels
How do you remember
5-HIAA for carcinoid?
P303 (picture)
Think of a 5-HIGH CAR pile up =
5-HIAA CARcinoid
What stimulation test can often elevate serotonin levels and cause symptoms of carcinoid syndrome? P303
Pentagastrin stimulation
How do you localize a GI
carcinoid?
P304
Barium enema, upper GI series with
small bowel follow-through, colonoscopy,
enteroscopy, enteroclysis, EGD, radiology
tests
What are the special
radiologic (scintigraphy)
localization tests?
P304
I-MIBG (131 metaiodobenzylguanidine)
In-octreotide
PET scan utilizing C-labeled HTP
What is the surgical
treatment?
P304
Excision of the primary tumor and single
or feasible metastasis in the liver (liver
transplant is an option with unresectable
liver metastasis); chemotherapy for
advanced disease
What is the medical
treatment?
P304
Medical therapy for palliation of the
carcinoid syndrome (serotonin antagonists,
somatostatin analogue [octreotide])
How effective is octreotide?
P304
It relieves diarrhea and flushing in more
than 85% of cases and may shrink tumor
in 10% to 20% of cases
What is a common
antiserotonin drug?
P304
Cyproheptadine
What is the overall prognosis?
P304
Two thirds of patients are alive at 5 years
What is the prognosis of
patients with liver metastasis
or carcinoid syndrome?
P304
50% are alive at 3 years
What does carcinoid tumor
look like?
P304
Usually intramural bowel mass; appears
as yellowish tumor upon incision
For appendiceal carcinoid, when is a right hemicolectomy indicated versus an appendectomy? P304
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 has the
highest rate of metastasis?
P304
Ileal primary tumor
Can a carcinoid tumor be
confirmed malignant by
looking at the histology?
P304
No, metastasis must be present to
diagnose malignancy
What is the correlation
between tumor size and
malignancy potential?
P305
Vast majority of 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? P305
Chemoembolization or radiofrequency
ablation
What are the overall survival
rates for carcinoid tumors at
5 years? 10 years?
P305
5 years = 70%; 10 years = 50%
What are the side effects of
colorectal carcinoid?
P305
Most common side effect is rectal bleeding
+/- vague abdominal pain/discomfort
