Polish Mother"s Memorial Hospital, Department of Genetics, Lodz, Poland

This is a case of a fetus with right kidney agenesis. In the images the right kidney is not visible in the normal location and the right renal artery is absent on Doppler. In front of the spine there was a cyst, which resembled the collection system of the kidney, but no kidney parenchyma or vessels were noted. The growth of the cyst was slow: proportionally slower than the growth of the fetus. The suspicion of right kidney agenesis with rudimentary ectopic kidney was set, although we could not exclude pelvic kidney. There was also mild tricuspid regurgitation.

After birth the diagnosis was confirmed and the baby did not require any treatment.

Images 1, 2: Power Doppler ultrasound; Coronal plane at the level of abdominal aorta and origins of renal arteries showing missing right renal artery (left image); and transverse plane showing left renal artery and cystic structure in front of the spine that we considered to be a right collection system without visible kidney parenchyma.

Images 3, 4: 2D ultrasonography; transverse planes showing a cystic structure in front of the spine corresponding with the right collection system without visible kidney parenchyma.

Image 5: A mild tricuspid regurgitation.