label: Gastrointestinal Stromal Tumor of the Gastrointestinal Tract
label_lc: gastrointestinal stromal tumor of the gastrointestinal tract
description: A stromal tumor that originates from the interstitial cells of Cajal. It may involve any part of the gastrointestinal tract. The majority of cases occur in the stomach. Morphologic variants include the epithelioid cell type, spindle cell type, and mixed cell type. Most cases contain KIT- or PDGFRA-activating mutations. Lesions with a diameter greater than 10cm and more than 5 mitotic figures per 50HPF tend to have a more aggressive clinical course. Until recently, surgery has been the only effective therapy for this tumor. However, many patients still experience recurrence. A KIT tyrosine kinase inhibitor, imatinib mesylate (also known as STI-571 or Gleevec), is now effective in the treatment of relapsed and unresectable cases.