BackgroundIt is rare to encounter massive hemothorax as a complication of pancreatic pseudocyst. In addition, as no obvious hypotension and abdominal discomfort were noted, it was difficult to consider gastrointestinal lesion a possibility.Case presentationA 54-year-old Taiwanese man had tightness on the left side of his chest and shortness of breath for 3 days. He had a history of acute pancreatitis 3 months ago. After history taking and a series of examinations including thoracocentesis and computed tomography of his abdomen and chest, the diagnosis was finally confirmed based on the high amylase levels in his pleural fluid.ConclusionsTreatment with distal pancreatectomy and splenectomy was subsequently successfully performed. Based on our experience, we briefly discuss the currently available treatment options for pancreatic pseudocyst.