A 30 year-old woman presented at the casualty department 12 days after having given birth to a healthy baby via normal vaginal delivery. She complained of increasing pain and a mass in her right flank. There were no complaints of nausea, vomiting, dysuria or abnormal bowel habits.
On examination, the patient was acutely distressed, in severe pain and was anaemic with an Hb of 5 g/dl. Her blood pressure was 151/71 mmHg and her pulse rate 125/minute. Physical examination revealed a severely distended abdomen with features of peritonitis.
An abdominal ultrasound revealed a large abdominal fluid collection and a CT scan was therefore requested. A contrast-enhanced CT scan demonstrated a large homogenous retroperitoneal fluid collection in the right flank, with a 25mm rounded, intensely enhancing focus located close to the inferior border of the collection. The collection displaced the bowel to the left and inferiorly, and the liver, superiorly.
The differential diagnosis included a ruptured ovarian artery aneurysm. As soon as the patient was stable, she was taken for ovarian artery embolization that was successfully accomplished. The patient recovered well in the ward.

CT daignosis; Overian artery aneurysm embolisation