GIST Flashcards
(32 cards)
A 79-year-old man is evaluated for epigastric pain, loss of appetite, and
early satiety. Upper endoscopy reveals a submucosal mass in the gastric
antrum. Endosonography shows a mass (4 × 6 cm) in the mid stomach arising
from the second layer (mucosa/lamina propria). Which tumor is most likely?
A) Carcinoid tumor.
B) GIST.
C) Lipoma.
D) Myoma.
Carcinoid
الخلاصة
*Carcinoid tumors originate from enterochromaffin cells in the deep mucosa (second layer).
*GIST typically arises from the muscularis propria (fourth layer).
*Lipomas usually arise from the submucosa (third layer).
*Myomas are extremely rare in the stomach and typically arise from the muscularis as well.
GIST
G
1-Gene mutations of poro-oncogens (c- kit 85% ,PDGFRA 5%،no mutation 10%)
*c- kit is responsible for control of thyrosine kinase activity on the cell membrane so when mutation occurs it will lose its control on throsine kinase leading to increase activity and there will be increase in proliferation of cell more than apoptosis leading into a tumor
ما هو ترتيب الاورام في git
1-Adenocarcinoma
2-Lymphoma
3-GIST
Carney’s triad
GPE
Gastric Gist
Pulmonary chondroma
Extra adrenal paraganglionoma
GIST
I
1-Interstitial cells of cajal: the source of gist
2-Imatinib
This is a receptor tyrosine kinase inhibitor. It inhibits the growth of GISTs and induces apoptosis.
It is FDA approved as a first line treatment of metastatic or unresectable GISTs, and as adjuvant therapy following complete resection of GIST with high-risk features.
o High-risk features include any ruptured GIST (recurrence risk is near 100%)26, tumor size > 10 cm,
or tumor size > 5 cm with > 5 mitoses/HPF.
o The FDA approved indication includes any GIST ≥ 3 cm.
Duration of treatment is unclear but is at least 3 years.
o Treatment for 3 years improves overall survival compared to 1 year.
Side effects of imatinib are periorbital edema, diarrhea, myalgia, musculoskeletal pain headache, and skin rash.
The standard dose is 400 mg once daily.
o A higher dose of 400 mg twice daily is indicated in patients with disease progression on standard dose, or in patients with exon 9 c-Kit mutation.
GIST
I
Investigations
1- CT scan, MRI, PET scan
2-EGD shows a submucosal mass with normal or ulcerated overlying mucosa.
Mucosal biopsies are usually non-diagnostic.
3-EUS shows a hypoechoic mass originating from the fourth sonographic wall layer (muscularis).
x FNA shows spindle cells with eosinophilic cytoplasm that stain positive for c-Kit
GIST
S
*Site ..2s (stomach,small intestine)
Surgery
Sunitinib
GIST
S
Spindle cells with eosinophilic cytoplasm that stain positive for c-Kit in FNA biopsy
GIST
*Staging
1-90% of GISTs are CD117 (+), 70% are CD34 (+).
2-leiomyomas are smooth muscle actin (+) and desmin (+)
3- schwannomas are S100 (+)
4- Patients with neurofibromatosis type 1 (von Recklinghausen disease) develop multiple small intestinal GISTs. These GISTs are c-Kit, PDGRA, and CD117 negative.
5-Gastric mass + 4th layer + Vimentin positive =Glomus tumor
GIST
S
*Solitary in most cases ,rare to be multiple
GIST
S
Sunitinib (Sutent®)
Inhibits multiple receptor tyrosine kinases.
It is FDA approved for the treatment of imatinib-resistant, metastatic, or unresectable GIST. The
standard dose is 50 mg/day.
x Regorafenib (Stivarga®)
This is a multikinase inhibitor that is FDA approved for the treatment of locally advanced, unresectable,
or metastatic GIST unresponsive to imatinib or sunitinib.
GIST
S..surgery(the corner stone of treatment)
*Indications:
>2cm any where
<2cm with risky signs (irregular borders, bleeding,ulcerating, heterogeneous)
*Principles of surgery
1-no wide safety margins.
2- no lymphadenectomy unless lns enlargment
3-if gastric: laparoscopic ressection.
4-if Intestinal: segmental ressection
5-follow up after ressection by ct every 6 months for 5 years
GIST
T
Types in pathology include:
1- spindle cell (70-80%), 2-epithelial (20-30%)
3-mixed type (< 5%).
An 18-year-old boy develops epigastric pain, diminished appetite, and nausea for several weeks.
CBC performed by his primary care provider is unremarkable, although LDH level is markedly
elevated. His pain continues and he is referred to a gastroenterologist for further management.
Endoscopy is performed, revealing multiple small duodenal and proximal small bowel masses
with a greenish tinge. Biopsies of the lesions are strongly positive for myeloperoxidase stain.
▶ Which of the following is the most likely diagnosis?
A. Gastrointestinal stromal tumor (GIST)
B. B-cell lymphoma
C. Glomus tumor
D. Leiomyoma
E. Granulocytic sarcoma
Granulocytic sarcoma (chloroma)
3.5-cm subepithelial mass is found in the stomach during upper endoscopy for dyspep-
sia. EUS reveals a hypoechoic 4th layer tumor. Biopsy with immunostaining reveals c-kit
(CD117) positivity.
GIST
A 2-cm subepithelial mass is found in the stomach during upper endoscopy for evaluation
of iron deficiency anemia. The endoscopy is otherwise normal. Subsequent EUS reveals an
extramural, anechoic, spherical structure at the site of the subepithelial bulge.
Duplication cyst
- A 1-cm subepithelial mass is found in the stomach during upper endoscopy for dyspepsia.
EUS reveals a hypoechoic 4th layer tumor. Biopsy with immunostaining reveals actin
positivity, but negative c-kit staining.
Liomyoma
A 2-cm subepithelial mass is found in the stomach during upper endoscopy for reflux
symptoms. The mass demonstrates a “pillow sign,” meaning that it indents with pressure
from the forceps, and slowly reforms upon withdrawal of the forceps. Subsequent EUS
reveals a hyperechoic, well-circumscribed, 3rd layer tumor.
Lipoma
Several subepithelial masses are found in the stomach during upper endoscopy for dyspep-
sia in the setting of a previous Billroth II procedure for peptic ulcer disease. The gastrin is
also elevated, and a secretin stimulation test is negative. The subepithelial masses range in
size from a subcentimeter to 2 cm, and are scattered throughout the stomach. Subsequent
EUS reveals the lesions to be in the 2nd and 3rd layers of the stomach wall and hypoechoic
in echotexture.
Carcinoid
1.5-cm subepithelial mass is found in the stomach during upper endoscopy for dyspep-
sia. EUS reveals a hypoechoic 4th layer tumor. Biopsy with immunostaining reveals actin
and vimentin positivity, but c-kit negativity.
Glomus tumor
2-cm subepithelial mass is found in the stomach during upper endoscopy for dys-
pepsia. EUS reveals a hypoechoic 4th layer tumor. Biopsy with immunostaining reveals
S-100 positivity.
Schawanoma
A 2-cm subepithelial pre-pyloric mass is found in the antrum of the stomach during upper
endoscopy for dyspepsia. The mass has a central umbilication. EUS reveals a hypoechoic
mass arising from the 3rd sonographic layer
Panceriatic rest
CD117 positive + 4th layer subepithelial mass
GIST
