Chapter 45: Carcinoid Tumors Flashcards

1
Q

What is a carcinoid tumor?

A

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

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2
Q

Why is it called “carcinoid”?

A

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

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3
Q

What are the common sites of occurrence?

A

Think “AIR”:

  1. Appendix (most common)
  2. Ileum
  3. Rectum
  4. Bronchus

Other sites:

  • jejunum
  • stomach
  • duodenum
  • colon
  • ovary
  • testicle
  • pancreas
  • thymus
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4
Q

What are the signs/symptoms?

A

Depends on location;

  • most cases are asymptomatic
  • also SBO
  • abdominal pain
  • bleeding
  • weight loss
  • diaphoresis
  • pellagra skin changes
  • intussusception
  • carcinoid syndrome
  • wheezing
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5
Q

Why SBO with carcinoid?

A

Classically = severe mesenteric fibrosis

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6
Q

What are the pellagra-like symptoms?

A
  1. Dermatitis
  2. Diarrhea
  3. Dementia
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7
Q

What causes pellagra in carcinoid patients

A

Decreased niacin production

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8
Q

What is carcinoid syndrome?

A

Syndrome of symptoms caused by release of substances from a carcinoid tumor

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9
Q

What are the symptoms of carcinoid syndrome?

A

Remember the acronym “B FDR”:

  • Bronchospasm
  • Flushing (skin)
  • Diarrhea
  • Right-sided heart failure (from valve failure)
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10
Q

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

A

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

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11
Q

Classic cardiac complication with carcinoid syndrome?

A

Tips:

  1. Tricuspid Insufficiency
  2. Pulmonary Stenosis
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12
Q

What is the incidence of carcinoid SYNDROME in patients who havea carcinoid TUMOR?

A

≈10%

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13
Q

What released substances cause carcinoid syndrome?

A

Serotonin and vasoactive peptides

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14
Q

What is the medical treatment for carcinoid syndrome?

A

Octreotide IV

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15
Q

What is the medical treatment of diarrhea alone?

A

Odansetron (Zofran®)—serotonin antagonist

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16
Q

How does the liver prevent carcinoid syndrome?

A

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

17
Q

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

A

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

18
Q

What tumors can produce carcinoid syndrome?

A
  • Liver metastases
  • Retroperitoneal disease draining into paravertebral veins
  • Primary tumor outside the GI tract, portal venous drainage e.g.,
    • ovary
    • testicular
    • bronchus
19
Q

What does the liver break down serotonin into?

A

5-hydroxyindoleacetic acid (5-HIAA)

20
Q

What percentage of patients with a carcinoid have an elevated urine5-HIAA level?

A

50%

21
Q

What are the associated diagnostic lab findings?

A

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

22
Q

What stimulation test can often elevate serotonin levels and causesymptoms of carcinoid syndrome?

A

Pentagastrin stimulation

23
Q

How do you localize a GI carcinoid?

A
  • Barium enema
  • upper GI series with small bowel follow-through
  • colonoscopy
  • enteroscopy
  • enteroclysis
  • EGD
  • radiology tests
24
Q

What are the special radiologic (scintigraphy) localization tests?

A
  • 131I-MIBG (131 metaiodobenzylguanidine)
  • 111In-octreotide
  • PET scan utilizing 11C-labeled HTP
25
Q

What is the surgical treatment?

A
  • Excision of the primary tumor and single or feasible metastasis in the liver (livertransplant is an option with unresectable liver metastasis)
  • chemotherapy for advanced disease
26
Q

What is the medical treatment?

A

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

27
Q

How effective is octreotide?

A

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

28
Q

What is a common antiserotonin drug?

A

Cyproheptadine

29
Q

What is the overall prognosis?

A

Two thirds of patients are alive at 5 years

30
Q

What is the prognosis of patients with liver metastasis or carcinoidsyndrome?

A

50% are alive at 3 years

31
Q

What does carcinoid tumor look like?

A

Usually intramural bowel mass; appears as yellowish tumor upon incision

32
Q

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

A
  • if the tumor is >1.5 cm
    • right hemicolectomy is indicated
  • if there are no signsof serosal or cecal involvement and tumor is <1.5 cm
    • appendectomy should be performed
33
Q

Which primary site has the highest rate of metastasis?

A

Ileal primary tumo

34
Q

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

A

No, metastasis must be present to diagnose malignancy

35
Q

What is the correlation between tumor size and malignancypotential?

A
  • Vast majority of tumors <2 cm are benign
  • in tumors >2 cm, malignancy potential is significant
36
Q

What treatments might you use for the patient with unresectableliver metastasis that is refractory to medical treatment

A

Chemoembolization or radiofrequency ablation

37
Q

Name the diagnostic modality:

50-year-old male with history of flushing, diarrhea, JVD with echorevealing right-sided heart failure

A

24-hour urinary 5-HIAA (5-hydroxyindoleacetic acid) level to work up carcinoid syndrome