Clinical History A 67-year-old man presented with the new onset of generalized abdominal pain. CT of the abdomen revealed a 3-cm mass at the root of the mesentery, for which he underwent exploratory laparotomy. Tissue biopsy of the mass revealed high-grade gastrointestinal stromal tumor. The mass was unresectable because of encasement of the superior mesenteric vessels. Despite neoadjuvant chemotherapy, the patient developed liver metastases. His chemotherapy regimen was altered, and he subsequently underwent MRI of the abdomen to evaluate his response to treatment.
