Gastrointestinal stromal tumors: Diagnosis and current management

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. They originate from the interstitial cells of Cajal in the myenteric plexus. GISTs can arise anywhere along the GI tract but the most common sites of origin are the stomach and small bowel. GISTs can occur at any age with different presentations. The discovery of the gain-of-function mutations in the KIT and PDGFRA genes (encoding tyrosine kinase receptor) led to the era of tyrosine kinase inhibitors (TKIs), such as imatinib and changed the management of these tumors. Surgery remains the treatment of choice for primary disease and can cure most patients. However, treatment with TKIs, usually in addition to surgery, can improve prognosis substantially in patients with large primary tumors and, advanced or metastatic disease. This chapter reviews the epidemiology, biology, pathology, and management of these tumors.