GISTs, Carcinoids, Etc Flashcards

1
Q

What cells do GISTs arise from?

A

Interstitial cells of Cajal (intestinal pacemakers in the myenteric plexus)

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2
Q

GISTs histologically stain positive for ?

A

c-kit (CD117) in 99%; CD34 in 80%; DOG1

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3
Q

Gastric carcinoids arise from?

A

enterochromaffin cells

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4
Q

GISTs occur most frequently in the ____

A
  1. stomach 2. small bowel 3. rectum; most common location in the small bowel is the jejunum and ileum
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5
Q

Survival indicators for GISTs

A

size at presentation, mitotic index, evidence of invasion into the lamina propria

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6
Q

Tumor that appears endoscopically as a submucosal smooth muscle tumor that extrinsically compresses the lumen

A

GIST

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7
Q

Staging workup of GIST

A

contrast enhanced CT Chest/ab/pelvis

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8
Q

GIST surgical treatment

A

wide local excision to negative gross margins. they do not require large margins and lymphadenectomy is not mandatory; take care to not disrupt capsule of the tumor

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9
Q

for a GIST, what is used for tumor grading

A

mitotic rate

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10
Q

Systemic therapy for ckit antibody in treatment for GIST

A

imatinib (gleevec)

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11
Q

What surgical margins should be obtained for gastric adenocarcinoma?

A

at least 5cm margins

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12
Q

Factors determining malignant potential of GISTs:

A

size of tumor, mitotic rate

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13
Q

Which patients with GISTs should receive gleevec?

A

those with tumors >3cm, >5mitotic figures/hpf, or those with metastatic disease

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14
Q

What is the criteria to undergo endoscopic mucosal resection for gastric cancer?

A

2cm less in diameter, well-differentiated, no penetration beyond submucosa (T1), no lymphovascular invasion, negative margins

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15
Q

Which gastric cancer is characterized by polymorphous infiltrate of small cells with associated reactive appearing follicles that express CD19, CD20, and CD22?

A

MALToma

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16
Q

How many lymph nodes should be obtained at minimum for gastric adenocarcinoma lymphadenectomy?

A

15 nodes

17
Q

What diagnostic imaging can be used to diagnose bile reflux?

A

HIDA scan - shows bile in stomach and sometimes esophagus

18
Q

A fasting serum gastrin ______ is pathognomic for gastrinoma.

A

1000 pg/mL

19
Q

Diagnostic test for gastrinoma:

A

secretin stimulation test

20
Q

When is neoadjuvant therapy recommended for gastric adenocarcinoma?

A

any node positive or locally advanced (T3) disease

21
Q

Most predictive prognostic factor for GISTS:

A

mitotic index

22
Q

True or false. Small bowel GISTS have a better prognosis than gastric GISTS.

A

false. it is worse

23
Q

What is the current gold standard for adequate lymph node number in staging gastric cancer?

A

16 lymph nodes

24
Q

characteristics of type 1 carcinoid:

A

most common; associated with pernicious anemia and chronic atrophic gastritis; less malignant potential and slow growing

25
Q

characteristics of type 2 carcinoid:

A

occurs in MEN 1 and Zollinger Ellison syndrome; intermediate malignant potential

26
Q

characteristics of type 3 carcinoid:

A

aggressive, solitary lesions associated with normal gastrin levels

27
Q

How do GISTs metastasize?

A

hematogenous spread, most commonly to liver and peritoneal surfaces

28
Q

What type of margins for resection are adequate for GISTs?

A

R0 or R1 margins

29
Q

Most common risk factor for development of gastric adenocarcinoma:

A

H. pylori infection

30
Q

When you use endoscopic mucosal resection with submucosal dissection for gastric cancer?

A

when less than or equal to 2cm diameter, well or moderately differentiated, without extension beyond submucosa (T1), no lymphovascular invasion, and negative margins

31
Q

Histologic features of MALToma:

A

polymorphus infiltrate of small cells with associated reactive appearing follicles and expression of CD19, CD20, and CD22

32
Q

Which subtype of MALToma is less likely to respond to abx eradication?

A

t(11;18) mutations; if this mutation is present radiation is indicated or rituximab

33
Q

Other predictors of response to H. Pylori treatment for MALToma:

A

depth of penetration (deep to submucosa is less responsive)
absence of AP-12-MALT 1 translocation
gastric site (proximal is more worrisome)
microsatellite instability
advanced age

34
Q

Treatment of MALToma that doesnt respond to H pylori or when patient is H pylori negative:

A

radiation treatment; chemo is used as salvage in those with radiation failure

35
Q

True or false. Surgical excision of MALToma is appropriate.

A

false

36
Q

Features of type 1 gastric neuroendocrine tumor:

A

female, multifocal, subcentimeter polypoid protrusions in body or fundus; associated with chronic atrophic gastritis and enterochromaffin-like cell hyperplasia; usually asymptomatic on presentation

37
Q

True or false. Type 1 and Type 2 gastric neuroendocrine tumors can be managed with endoscopic removal or surveillance every 1-2 years when they are less than 1 cm without risk factors.

A

true