GISTs, Carcinoids, Etc

Question 1

What cells do GISTs arise from?

Answer 1

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

Question 2

GISTs histologically stain positive for ?

Answer 2

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

Question 3

Gastric carcinoids arise from?

Answer 3

enterochromaffin cells

Question 4

GISTs occur most frequently in the ____

Answer 4

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

Question 5

Survival indicators for GISTs

Answer 5

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

Question 6

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

Answer 6

GIST

Question 7

Staging workup of GIST

Answer 7

contrast enhanced CT Chest/ab/pelvis

Question 8

GIST surgical treatment

Answer 8

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

Question 9

for a GIST, what is used for tumor grading

Answer 9

mitotic rate

Question 10

Systemic therapy for ckit antibody in treatment for GIST

Answer 10

imatinib (gleevec)

Question 11

What surgical margins should be obtained for gastric adenocarcinoma?

Answer 11

at least 5cm margins

Question 12

Factors determining malignant potential of GISTs:

Answer 12

size of tumor, mitotic rate

Question 13

Which patients with GISTs should receive gleevec?

Answer 13

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

Question 14

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

Answer 14

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

Question 15

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

Answer 15

MALToma

Question 16

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

Answer 16

15 nodes

Question 17

What diagnostic imaging can be used to diagnose bile reflux?

Answer 17

HIDA scan - shows bile in stomach and sometimes esophagus

Question 18

A fasting serum gastrin ______ is pathognomic for gastrinoma.

Answer 18

1000 pg/mL

Question 19

Diagnostic test for gastrinoma:

Answer 19

secretin stimulation test

Question 20

When is neoadjuvant therapy recommended for gastric adenocarcinoma?

Answer 20

any node positive or locally advanced (T3) disease

Question 21

Most predictive prognostic factor for GISTS:

Answer 21

mitotic index

Question 22

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

Answer 22

false. it is worse

Question 23

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

Answer 23

16 lymph nodes

Question 24

characteristics of type 1 carcinoid:

Answer 24

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

Question 25

characteristics of type 2 carcinoid:

Answer 25

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

Question 26

characteristics of type 3 carcinoid:

Answer 26

aggressive, solitary lesions associated with normal gastrin levels

Question 27

How do GISTs metastasize?

Answer 27

hematogenous spread, most commonly to liver and peritoneal surfaces

Question 28

What type of margins for resection are adequate for GISTs?

Answer 28

R0 or R1 margins

Question 29

Most common risk factor for development of gastric adenocarcinoma:

Answer 29

H. pylori infection

Question 30

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

Answer 30

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

Question 31

Histologic features of MALToma:

Answer 31

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

Question 32

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

Answer 32

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

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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

Question 35

True or false. Surgical excision of MALToma is appropriate.

Answer 35

false

Question 36

Features of type 1 gastric neuroendocrine tumor:

Answer 36

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

Question 37

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.

Answer 37

true