The anatomic splenic flexure: an ultrasonic renal impostor.

The anatomic splenic flexure of the colon occupies the left renal fossa in patients with agensis or ectopic of the left kidney. On ultrasonic scans, the colon filled with stool or fluid may simulate a kidney or mass. This mass is often comma shaped on the transverse scans and lacks good definition of its inferior margin on longitudinal scans. An evaluation of a patient with only right renal function should combine radiologic techniques with ultrasonography to establish the correct diagnosis.