<prompt> Treatment of Zollinger Ellison syndrome -Total gastrectomy with removal of tumourPartial gastrectomyExcision of tumour aloneH2, receptor antogonist  <response>: GISTs: MC mesenchymal tumor of the GI tract MC primary site for GIST: Stomach 6070 small bowel 2025 colorectum and esophagus 5 each. Most GISTs are positive for CD-117 95, BCL-2 80, CD-34 70 Types: Spindle cell 70 and Epitheloid 30Pathology: Arise from the muscularis propria and most likely originate from the cells of Cajal Expression of the receptor tyrosine kinase KIT CD 117, 5 express platelet derived growth factor receptor alpha PDGFRA. PDGFRA mutations in GIST appear to confer a very favorable prognosis with low risk of recurrence. Spindle cell pattern 70 of GIST is more common than epitheloid or round cell pattern 30. New tumor markers of GIST: DOG-1 discovered on GIST-1 and protein kinase C-thetaClinical features: Patients usually present after the fourth decade, with the mean age of 60 years at diagnosis. MC presentations of gastric GISTs: GI bleeding and pain or dyspepsia.Carney triad Association of extra-adrenal paragangliomas, pulmonary chondromas and multifocal GISTDiagnosis: CT: IOC for evaluation of primary tumor and accurate staging PET-CT: Gold standard for recurrent GIST Percutaneous or endoscopic biopsy should only be performed if the results would obviate the need for surgeryQ.Treatment: Bleeding manifestation is the MC indication for surgery. GIST should be treated with segmental resectionQ margins of 1cm LN metastasis are uncommon, regional lymphadenectomy is not recommended Intraoperative incisional biopsy prior to resection should be avoided, because it risks tumor spillage Imatinib selective inhibitor of type 3 tyrosine kinase KIT, is approved for use in CD117-positive unresectable and metastatic GISTs. Functional imaging of GIST with 18FDG-PET scanning represents a useful diagnostic modality for early-response assessment with imatinib therapy. Sunitinib is used in imatinib-refractory disease.Prognosis: Tumor size is a predominant factor for survival in surgical series for primary GIST. MC sites of disease failure after complete resection: Liver, omentum or peritoneal cavity. Half to two third primaries will have disease failure within the liver and nearly 40 will have liver as the only site of failure. Generally hepatic involvement is multifocal. Median time to recurrence after resection of primary GIST is 2 years. 