most common mesenchymal neoplasms of the gastrointestinal tract.

GISTs arise in the smooth muscle pacemaker interstitial cell of Cajal, or similar cells

They are defined as tumors whose behavior is driven by mutations in the KIT gene (85%), PDGFRA gene (10%), or BRAF kinase (rare).

95% of GISTs stain positively for KIT (CD117).

Most (66%) occur in the stomach and gastric GISTs have a lower malignant potential than tumors found elsewhere in the GI tract

ulcerations on these tumors can represent tumor necrosis and known marker of malignant behavior

these tumors tend to bleed easily after biopsy