The positive psoas sign on the left is a non-specific sign, but should raise the possibility of retroperitoneal pathology. The patient's age and clinical presentation were concerning for a possible aortic aneurysm rupture and an urgent non-contrast CT was subsequently obtained which confirmed a ruptured aortic aneurysm with a large left retroperitoneal hematoma. The imaging findings were confirmed at surgery. The patient had an uneventful post-operative recovery period.