Distinctive features of gastrointestinal stromal tumors arising from the colon and rectum

Gastrointestinal stromal tumors (GISTs) are rare, yet they are the most common mesenchymal neoplasm in the gastrointestinal tract with an annual incidence in the United States of 3,300–6,000 new cases a year (1). Postulated to arise from the interstitial cell of Cajal, 75–80% of cases have mutations in the C-KIT proto-oncogene in exons 9, 11, 13, or 17, while an additional 10% possess platelet-derived growth factor receptor (PDGFR) mutations (2-4). A clear understanding of the tumor biology has led to improved treatment of these sarcomatous neoplasms of the gastrointestinal tract. In particular, knowledge of these genetic abnormalities led to the use of multi-targeted tyrosine kinase inhibitors (imatinib, sunitinib, regorafenib), which have revolutionized the treatment of solid tumors (5-8)