We present the case of a 43-year-old man, with a history of diabetes, who was admitted for moderate acute pancreatitis. Two weeks later, he reported acute pain in the left hemiabdomen and nausea, with no other symptoms. On examination, a large occupation of the left hemiabdomen was palpated without peritoneal irritation. Laboratory tests: elevated triglycerides and lipase, other biochemistry, haemogram and coagulation normal. During the examination, the patient suffered syncope and his haematocrit dropped from 40 to 21%, requiring transfusion of 6 red blood cell concentrates, and he remained stable. Imaging tests revealed a haemorrhagic pancreatic pseudocyst measuring 17 x 27 cm in diameter. The patient was admitted to the ICU where he remained stable. One week later, the patient was scheduled for surgery with a cysto-jejunostomy. The postoperative period was uneventful and the patient was discharged one week after the operation.