Malignant extra-gastrointestinal stromal tumor of the pancreas: report of two cases and review of the literature.

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that arise from the gastrointestinal tract. In rare cases, these tumors are found in intra-abdominal sites unrelated to the gastrointestinal tract, such as the mesentery, omentum and retroperitoneum. However, pancreatic extra-gastrointestinal stromal tumors are extremely rare, with only 14 previous cases reported. A 61-year-old man with no clinical symptoms had a routine check-up, during which an abdominal mass located in the pancreas tail was detected. Abdominal surgery was performed with resection of the pancreas tail and the spleen, and he was diagnosed with low-risk GISTs. Another 60-year-old man with no clinical symptoms underwent Computed tomography which revealed a well-demarcated tumor, 6 cm in diameter, in the head of the pancreas. He was diagnosed with pancreatic GISTs. Here, we describe two rare cases of pancreatic GISTs and review the cases previously reported in the literature.