Misc

Question 1

What cells do GIST tumors arise from?

Answer 1

Interstitial cells of Cajal expressing KIT protein CD117

Question 2

What gut structure do most GIST tumors arise

Answer 2

Muscularis propria

Question 3

What is worldwide incidence of GIST

Answer 3

5-10k annually

Question 4

Are GISTs usually benign or malignant?

Answer 4

Benign 70-80%

Question 5

Which organ has highest frequency of benign GIST

Answer 5

Stomach

Question 6

What is most common organ of GIST inolvement

Answer 6

Stomach 47%>small intestine 35%>colon 5%, rectum 7%

Question 7

What are CT characteristics of GIST?

Answer 7

Variable enhancement! Ulceration or cystic degeneration. Exophytic.

Question 8

Where do GIST tumors metastasize

Answer 8

Liver, peritoneal cavity

Lungs, pleura, soft tissues

Question 9

Ddx of GIST

Answer 9

Adenocarcinoma
Lymphoma
Peritoneal carcinomatosis
Carcinoid
Metastasis
Leiomyoma

Question 10

What criteria are used to follow GIST lesions treated by imatinib

Answer 10

Choi
Response 10% decrease in size, 15% decrease in density of lesion
Small increase may occur in early response
PET CT good to monitor response and mets