Mediastinal pancreatic pseudocyst masquerading as diffuse alveolar haemorrhage.

Pancreatic pseudocyst formation with extension into the mediastinum is an uncommon complication of pancreatitis that can result in numerous pulmonary and cardiac complications. We present a case of a 56-year-old man with a history of recurrent pancreatitis who presented with haemoptysis. His initial workup was consistent with diffuse alveolar haemorrhage for which he was treated with glucocorticoids. After failure to improve, further imaging demonstrated a complex fluid collection in the mediastinum consistent with extension of his pre-existing pancreatic pseudocyst, leading to erosion into the right lower lobe of the lung. This case highlights a rare pulmonary complication of pancreatitis and underscores the importance of proper identification of this condition to guide successful management.