Extra-gastrointestinal stromal tumor presenting as hemorrhagic pancreatic cyst diagnosed by EUS-FNA

Context: Pancreatic gastrointestinal stromal tumors (GIST) are rare mesenchymal tumor with only 6 cases reported to date. We report a case of pancreatic GIST presenting as hemorrhagic cyst. Case report: A 63-year-old female with past medical history of hypertension and pancreatic mass presented with fatigue. She was found to have anemia requiring blood transfusion. An abdominal CT scan revealed an 11x16 cm cystic mass at the pancreatic body that had increased in size compared with previous CT scan. Endoscopic ultrasound confirmed a large complex pancreatic mass and fine needle aspiration demonstrated gross bloody fluid. Cytology revealed a spindle cell lesion. Immunohistochemistry from cyst wall biopsy was strongly positive for CD34 and CD117 confirming the diagnosis of pancreatic GIST. Conclusion: We report a case of pancreatic GIST which presented as hemorrhagic cyst. Endoscopic ultrasound guided fine needle aspiration plays an important role in the diagnosis. Although it is an uncommon tumor, pancreatic GIST should be in differential diagnosis of hemorrhagic pancreatic cystic lesions as well as a rare cause of solid pancreatic lesions.