Carcinoid Tumors, C46 P301-305

Question 1

What is a carcinoid tumor?

P301

Answer 1

Tumor arising from neuroendocrine cells
(APUDomas), a.k.a. Kulchitsky cells;
basically, a tumor that secretes serotonin

Question 2

Why is it called “carcinoid”?

P301

Answer 2

Suffix “-oid” means “resembling”; thus,
carcinoid resembles a carcinoma but is
clinically and histologically less aggressive
than most GI carcinomas

Question 3

How can you remember that
Kulchitsky cells are found in
carcinoid tumors?
P301

Answer 3

Think: “COOL CAR” or KULchitsky

CARcinoid

Question 4

What is the incidence?

P301

Answer 4

Between 0.2% and 1.0% and about 25%

of all small bowel tumors

Question 5

What are the common sites
of occurrence?
P301

Answer 5

“AIR”:
1. Appendix (most common)
2. Ileum
3. Rectum
4. Bronchus
Other sites: jejunum, stomach,
duodenum, colon, ovary, testicle,
pancreas, thymus

Question 6

What are the signs/
symptoms?
P301

Answer 6

Depends on location; most cases are
asymptomatic; also SBO, abdominal
pain, bleeding, weight loss, diaphoresis,
pellagra skin changes, intussusception,
carcinoid syndrome, wheezing

Question 7

Why SBO with carcinoid?

P301

Answer 7

Classically = severe mesenteric fibrosis

Question 8

What are the pellagra-like
symptoms?
P302

Answer 8

Think “3-D”:

1. Dermatitis
2. Diarrhea
3. Dementia

Question 9

What causes pellagra in
carcinoid patients?
P302

Answer 9

Decreased niacin production

Question 10

What is carcinoid syndrome?

P302

Answer 10

Syndrome of symptoms caused by release

of substances from a carcinoid tumor

Question 11

What are the symptoms of
carcinoid syndrome?
P302

Answer 11

Remember the acronym “B FDR”:
Bronchospasm

Flushing (skin)
Diarrhea
Right-sided heart failure (from valve
   failure)

Question 12

What is a complete memory
aid for carcinoid?
P302 (picture)

Answer 12

Think: B FDR = CARcinoid, or “Be FDR

in a cool CAR” (COOL= KULchitsky cells)

Question 13

Why does right-sided heart
failure develop but not
left-sided heart failure?
P302

Answer 13

Lungs act as a filter (just like the liver);
thus, the left heart doesn’t see all the
vasoactive compounds

Question 14

What is the incidence of
carcinoid SYNDROME in
patients who have a
carcinoid TUMOR?
P302

Answer 14

≈10%

Question 15

What released substances
cause carcinoid syndrome?
P302

Answer 15

Serotonin and vasoactive peptides

Question 16

What is the medical treatment
for carcinoid syndrome?
P302

Answer 16

Octreotide IV

Question 17

What is the medical
treatment of diarrhea alone?
P302

Answer 17

Odansetron (Zofran®)—serotonin

antagonist

Question 18

How does the liver prevent
carcinoid syndrome?
P303

Answer 18

By degradation of serotonin and the
other vasoactive peptides when the
tumor drains into the portal vein

Question 19

Why does carcinoid
syndrome occur in some
tumors and not in others?
P303

Answer 19

Occurs when venous drainage from the
tumor gains access to the systemic circulation
by avoiding hepatic degradation
of the vasoactive substances

Question 20

What tumors can produce
carcinoid syndrome?
P303

Answer 20

Liver metastases
Retroperitoneal disease draining into
    paravertebral veins
Primary tumor outside the GI tract,
    portal venous drainage (e.g., ovary,
    testicular, bronchus), or both

Question 21

What does the liver break
down serotonin into?
P303

Answer 21

5-hydroxyindoleacetic acid (5-HIAA)

Question 22

What percentage of patients
with a carcinoid have an
elevated urine 5-HIAA level?
P303

Answer 22

50%

Question 23

What are the associated
diagnostic lab findings?
P303

Answer 23

Elevated urine 5-HIAA as well as
elevated urine and blood serotonin
levels

Question 24

How do you remember
5-HIAA for carcinoid?
P303 (picture)

Answer 24

Think of a 5-HIGH CAR pile up =

5-HIAA CARcinoid

Question 25

What stimulation test can
often elevate serotonin
levels and cause symptoms
of carcinoid syndrome?
P303

Answer 25

Pentagastrin stimulation

Question 26

How do you localize a GI
carcinoid?
P304

Answer 26

Barium enema, upper GI series with
small bowel follow-through, colonoscopy,
enteroscopy, enteroclysis, EGD, radiology
tests

Question 27

What are the special
radiologic (scintigraphy)
localization tests?
P304

Answer 27

I-MIBG (131 metaiodobenzylguanidine)
In-octreotide
PET scan utilizing C-labeled HTP

Question 28

What is the surgical
treatment?
P304

Answer 28

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

Question 29

What is the medical
treatment?
P304

Answer 29

Medical therapy for palliation of the
carcinoid syndrome (serotonin antagonists,
somatostatin analogue [octreotide])

Question 30

How effective is octreotide?

P304

Answer 30

It relieves diarrhea and flushing in more
than 85% of cases and may shrink tumor
in 10% to 20% of cases

Question 31

What is a common
antiserotonin drug?
P304

Answer 31

Cyproheptadine

Question 32

What is the overall prognosis?

P304

Answer 32

Two thirds of patients are alive at 5 years

Question 33

What is the prognosis of
patients with liver metastasis
or carcinoid syndrome?
P304

Answer 33

50% are alive at 3 years

Question 34

What does carcinoid tumor
look like?
P304

Answer 34

Usually intramural bowel mass; appears

as yellowish tumor upon incision

Question 35

For appendiceal carcinoid,
when is a right
hemicolectomy indicated
versus an appendectomy?
P304

Answer 35

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

Question 36

Which primary site has the
highest rate of metastasis?
P304

Answer 36

Ileal primary tumor

Question 37

Can a carcinoid tumor be
confirmed malignant by
looking at the histology?
P304

Answer 37

No, metastasis must be present to

diagnose malignancy

Question 38

What is the correlation
between tumor size and
malignancy potential?
P305

Answer 38

Vast majority of tumors 2 cm, malignancy

potential is significant

Question 39

What treatments might you
use for the patient with
unresectable liver metastasis
that is refractory to medical
treatment?
P305

Answer 39

Chemoembolization or radiofrequency

ablation

Question 40

What are the overall survival
rates for carcinoid tumors at
5 years? 10 years?
P305

Answer 40

5 years = 70%; 10 years = 50%

Question 41

What are the side effects of
colorectal carcinoid?
P305

Answer 41

Most common side effect is rectal bleeding

+/- vague abdominal pain/discomfort