Radiologic findings in malignant gastrointestinal stromal tumors.

In this pictorial essay, we describe the computed tomographic and magnetic resonance imaging appearances of primary and metastasized gastrointestinal stromal tumors. These nonepithelial tumors arise from the muscularis propria in the wall of the gastrointestinal tract and are thought to originate from Cajal cells in the interstitium of intestinal pacemaker tissue. These tumors are found in the stomach, small bowel, colon, rectum, and esophagus; they may also develop as primary tumors of the omentum, mesentery, or retroperitoneum. The clinical features and radiologic differential diagnosis of gastrointestinal stromal tumors are discussed.