ABSTRACT
Bleeding from pancreatic pseudocyst is a rare complication. Furthermore, massive upper gastrointestinal (GI) bleeding from gastro-cystic fistula formation and intracystic bleeding are both extremely rare and are also potentially fatal. A 53-year-old male was referred to the emergency room with melena and hematemesis. An urgent endoscopy revealed a massive gastric hematoma but showed no specific bleeding focus. Gastrocystic fistula formation and intracystic bleeding leakage to the stomach were suspicious in the follow-up endoscopy. A contrast-enhanced computed tomography scan demonstrated splenic artery pseudoaneurysm and extravasation of contrast media into the cyst that was abutted to the greater curvature side of the stomach. A splenic artery embolization was performed and no further bleeding occurred after embolization. Upper GI bleeding from gastro-cystic fistula and intracystic bleeding are rare but possible. Therefore, this possibility should be considered in the unknown cause of an upper GI bleeding in a patient with pancreatic pseudocyst.