GIST is the second most common benign polypoid lesion in the stomach (accounts for 70%). It is a mesenchymal tumour expressing a tyrosine k...
GIST is the second most common benign polypoid lesion in the stomach (accounts for 70%). It is a mesenchymal tumour expressing a tyrosine kinase growth factor receptor. In total, 60% are found in the submucosal stomach, and growth may also be outside the stomach, being extra- or intra-luminal. A total of 30% of GISTs are seen in the small bowel and 7% are ano-rectal. Lesions less than 5 cm without evidence of invasion are most likely benign. Oesophageal, colonic and ano-rectal GISTs are usually malignant (i.e. leiomyosarcoma). GIST is more common in patients with neurofibromatosis type-1.
if >5 cm, malignancy should be considered
BARIUM MEAL
• Submucosal mass, forming an obtuse angle with the gastric wall in profile• No change to the stomach’s mucosal surface—areae gastricae maintained• Focal areas of ulceration
CT
• Smooth, large (e.g. 30 cm) solid mass sometimes with cystic areas and a sizeable exophytic component.• Peripheral enhancement—large vessels or a vascular blush are common.• Central low attenuation representing necrosis, haemorrhage and cyst formation.• Large GISTs show a crescent-shaped area of necrosis (Torricelli-Bernoulli sign).• Large cavitating GISTs may fistulate to the gut lumen.• Nodal involvement is rare—another primary is more likely!• Malignant lesions commonly metastasise to the liver and peritoneum.
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