Gastrointestinal stromal tumors (GIST)By mahyarHistory: 34 Y/M with nausea, vomiting, weight loss and hematemesis Findings:
:: CT 1 ::CECT demonstrates homogeneously enhancing mural mass.
:: CT 2 ::CECT demonstrateshomogeneously enhancingmural mass.
:: CT 3 ::CECT demonstrateshomogeneously enhancingmural mass.
:: CT 4 ::CECT demonstrateshomogeneously enhancingmural mass.
:: Endoscopy 1 ::Endoscopy greater curvature of the stomach
:: Endoscopy 2 ::Endoscopy greater curvature of the stomach
:: Fluoroscopy 1 ::DSA Discussion: Gastrointestinal stromal tumors (GIST) make up only 1% of neoplasms of the GI tract. May be found throughout the length of the GI tract, but are most commonly found in the stomach. Second most common nonepithelial malignant gastric tumor after lymphoma, reported incidence of 4 per million persons. Pathology: Visceral sarcomas, previously classified as leiyomyomas, leiomyosarcomas, and leiomyoblastomas. Now classified as GISTs with a range of biological behaviors from low grade to high grade malignancies. Traditionally, tumor size (>5cm) and microscopic findings were used to define malignancy including: increased cell size, increased cell irregularity, lack of cell differentiation, >5 mitoses per 50 HPF, presence of cells with hyperchromic and multiple nuclei. Proposed to arise from the interstitial cell of Cajal, an intestinal pacemaker cell of mesodermal origin found in the myenteric plexus, submucosa, and muscularis propria. GISTs have similar cell markers to those of normal Cajal cells: c-kit receptor (CD117), myeloid stem cell antigen CD34, variably positive for smooth-muscle actin, usually negative for desmin. Most GISTs have a gain-of-function mutation in the c-kit proto-oncogene, which results in ligand-independent activation of the KIT receptor tyrosine kinase and an unopposed stimulus for cell growth. Previously thought to be smooth muscle neoplasms but now accepted to have: Myogenic features (smooth muscle GIST). Neural features (GI autonomic nerve tumor). Myogenic and neural features (mixed GIST). Clinical Presentation: Most commonly present in the 6th and 7th decades but may occur at any age, including the pediatric population, and are evenly distributed between the sexes. Typically present with GI bleeding, pain and weight loss. Due to large size, lesions often develop central ischemia and necrosis that leads to bleeding. Rarely, free rupture may occur with intraperitoneal bleeding and the presentation of an acute abdomen. Other symptoms related to location may occur e.g. nausea and vomiting due to gastric outlet obstruction. Palpable mass present in 20-50% of patients. Evaluation: UGI: typically shows a mass with intact mucosa, although mucosal ulceration may be present. EGD: extrinsic mass with normal overlying mucosa. Bopsy most often reveals normal mucosa as the majority of lesions are deep. EUS: allows for identification of the depth and local extent of tumor. CT: most useful means of evaluating size and location relative to surrounding structures as well as the presence of metastatic disease (present in < 20% of patients). Differential diagnosis: Gastric lymphoma, Sarcoma invading stomach, Exophytic gastric carcinoma, Submucosal GI lipoma Diagnosis confirmation: Surgery / Histo Category: Gastrointestinal Region / Organ: GI-Stomach Etiology: neoplastic References: High-Yield Imaging: Interventional, By Charles Burke, Robert Dixon, Matthew A. Mauro, MD, Kieran Murphy, MD, Kenneth Thomson, MD, Anthony Venbrux, MD and Christoph L. Zollikofer, MD Diagnostic imaging. Abdomen / Michael P. Federle ... let al.].- 1st ed. Get more for Gastrointestinal stromal tumors (GIST) Peer-reviewed resources Literature  More publications about Gastrointestinal stromal tumors (GIST) Challenge yourself with the case quiz! |