An Incidentally Discovered Primary Hepatic Gastrointestinal Stromal Tumor Treated by Surgical Resection and Adjuvant Imatinib Therapy: A Case Report

Abstract

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors derived from precursors of the interstitial cells of Cajal that commonly arise from the stomach or small intestine. These tumors usually contain KIT and/or PDGFRA mutations, which encode type III receptor tyrosine kinases. Approximately 10% of GISTs originate from sites other than the gastrointestinal tract, such as the mesentery, urinary bladder, retroperitoneum, pancreas, gallbladder, and liver. These tumors are hypothesized to originate from interstitial Cajal-like cells or undifferentiated pluripotent mesenchymal cells outside the gastrointestinal tract. Primary hepatic GISTs are rare, with most hepatic GISTs being secondary. Here, we report the case of a 69-year-old woman with a rare primary hepatic GIST. The hepatic GIST, measuring 13.5 cm, was incidentally discovered in the right liver lobe and exhibited heterogeneous arterial phase hyperenhancement, washout, diffusion restriction, low signal intensity in the hepatobiliary phase, intratumoral hemorrhage, necrosis, and fluid-fluid levels. Imaging revealed no evidence of extrahepatic primary lesions. GIST was pathologically confirmed via percutaneous biopsy and subsequent surgical resection. Despite adjuvant imatinib therapy, the tumor recurred with peritoneal seeding 15 months postoperatively. © 2023 Korean Society of Magnetic Resonance in Medicine.