GIST 间质瘤定义.pdfVIP

Gastrointestinal stromal tumor 1 Gastrointestinal stromal tumor Gastrointestinal stromal tumor Classification and external resources Histopathologic image of gastrointestinal stromal tumor of the stomach. Hematoxylin-eosin stain. DiseasesDB 33849 [1] MeSH D046152 [2] Endoscopic image of GIST in fundus of stomach, seen on retroflexion. Same GIST seen on forward view of the endoscope showing overlying clot. A gastrointestinal stromal tumor (GIST) is one of the most common mesenchymal tumors of the gastrointestinal tract (1-3% of all gastrointestinal malignancies). They are typically defined as tumors whose behavior is driven by mutations in the Kit gene or PDGFRA gene, and may or may not stain positively for Kit.[3] Signs and symptoms Patients present with trouble swallowing, gastrointestinal hemorrhage or metastases (mainly in the liver). Intestinal obstruction is rare, due to the tumors outward pattern of growth. Often, there is a history of vague abdominal pain or discomfort, and the tumor has become rather large by time the diagnosis is made. Generally, the definitive diagnosis is made with a biopsy, which can be obtained endoscopically, percutaneously with CT or ultrasound guidance or at the time of surgery. Diagnosis As part of the analysis, blood tests and CT scanning are often undertaken (see the radiology section). A biopsy sample will be investigated under the microscope. The histopathologist identifies the characteristics of GISTs (spindle Gastrointestinal stromal tumor 2 cells in 70-80%, epitheloid aspect in 20-30%). Smaller tumors can usually be found to the muscularis propria layer of the intestinal wall. Large ones grow, mainly outward, from the bowel wall until the point where they outstrip their blood supply and necrose (die) on the inside, forming a cavity that may eventually come to communicate with the bowel lumen. When GIST is suspected—as opposed to other causes for similar tumors—the pathologist can use immunohistochemistry (specific antibodies