We present the case of a patient who had a large pseudocyst in the right adrenal gland, which was ruptured following blunt abdominal trauma, leading to a voluminous hemorrhage in retroperitoneum. A 29-year old female patient was admitted in the emergency room following a fall from stairs with trauma in right flank. She underwent a computerized tomography that evidenced a large retroperitoneal collection, with no apparent renal damage. She was submitted to surgery, where a large ruptured cyst was observed, originating from the upper portion of the right adrenal gland. Cystic diseases of adrenal gland are rare. Highly voluminous cysts can be damaged in cases of blunt trauma to the lumbar region leading to large hematomas in retroperitoneum.