Gastrointestinal stromal tumor (GIST) is the most common human sarcoma and the
most common mesenchymal tumor of the gastrointestinal (GI) tract. About 85% of the
time GIST tumors are activated by the mutation in either KIT or PDGFRA (Platelet
Derived Growth Factor Receptor Alpha. GISTs may originate in the omentum or
mesentery. Most GISTs are spherical or ovoid. The tumors generally are enclosed by a
pseudo capsule and rarely infiltrate within the wall of the GI tract. They often grow in an
exophytic pattern. (insert a image )
GISTs tumors can occur throughout the GI tract. They are most common in the stomach
(60%) and small intestine: jejunum and ileum (30%) It’s rare to see GIST in the
duodenum (5%), rectum (3%), colon (1%), and esophagus (<1%).
The size thresholds used in this staging system are 2, 5, and 10 cm of the
greatest tumor diameter. Regional nodal metastasis is extremely rare in GIST,
except in SDH‐deficient GISTs, which tend to be less aggressive than most other
GISTs despite nodal involvement. In the absence of information on regional
lymph node status, cN0 is appropriate; the specification NX should not be used.
The presence of any metastasis is designated as M1. The morphologic subtypes
of GIST include spindle cell (70%), epithelioid (20%), and mixed‐cell types.