A male infant in the Children's Clinical Hospital, with a single kidney and lesion in the pelvis, is referred for an follow-up ultrasound scan.
At ultrasound there is a single kidney with a septum at the border of the middle and upper thirds, like an end-to-end fused kidneys. In the pelvis behind the urinary bladder (in the projection of the uterus, if it were a girl), there is a cyst-like lesion with echo-dense contents, like a fluid level (cyst with hemorrhage?), at CFM blood flow through the capsule, presumably a Mullerian duct cyst.