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Medicine

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Liver & GIT

Question
27 out of 27
 

All of the following are true about GIST except? (AIIMS Nov 2010)



A Duodenum is the most common site

B It is well encapsulated

C It shows areas of ulceration and necrosis

D PET is used for prognosis

Ans. A Duodenum is the most common site

Leiomyosarcomas and GISTs

1. Leiomyosarcomas and GISTs make up 1–3% of gastric neoplasms.

2. They most frequently involve the anterior and posterior walls of the gastric fundus.

They often ulcerate and bleed.

3. All such tumors should be analyzed for a mutation in the c-kit receptor.

4. Clinical feature : a. Dysphagia b. Gastrointestinal Hemorrhage c.metastases (mainly in the liver).

5. Definitive diagnosis of dysphagia made with a biopsy.

Pathophysiology

1. GISTs are tumors of connective tissue, i.e. sarcomas; unlike most gastrointestinal tumors, they are non-epithelial. 70% occur in the stomach, 20% in the small intestine and less than 10% in the esophagus.

2. GISTs arise from interstitial cells of Cajal (ICC), that are normally part of the autonomic nervous system of the intestine. They serve a pacemaker function in controlling motility.

3. Even those lesions that appear benign on histologic examination may behave in a malignant fashion.

4. These tumors rarely invade adjacent viscera and characteristically do not metastasize to lymph nodes, but they may spread to the liver and lungs.

Treatment:

1. The treatment of choice is surgical resection.

2. Combination chemotherapy should be reserved for patients with metastatic disease.

3. GISTs are unresponsive to conventional chemotherapy; ~50% of patients response and prolonged survival when treated with imatinibmesylate, a selective inhibitor of the c-kit tyrosine kinase.

4. Patients refractory to imatinib benefit from sunitinib, another inhibitor of the c-kit tyrosine kinase.

Liver & GIT Flashcard List

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