Fécamp, France.

Case report

A 25-year-old woman, with non-contributive personal and familial medical history, and normal first and second trimester prenatal ultrasonography, presented a 32 weeks. Following images shows findings we could observe.

Images 1, 2: Image 1 shows a transverse scan at the level of renal pelvises. The left renal pelvis shows a mild pyelectasis. Image 2 shows decreased parenchymal thickness of the left kidney (cortico-medullary border is difficult to recognize).

Images 3, 4: Image 2 shows enlargement and pyelectasis of the left kidney (sagittal view). The image 3 shows sagittal view of the right (normal) fetal kidney.

Images 5, 6: Images show pyelectasis of the left fetal kidney with mild dilatation of the proximal part of the left ureter (U). This view ruled out a pyeloureteral junction obstruction.

The images above suggest three possible diagnoses:

• vesico-ureteral reflux with or without ectopic termination of the ureter;

• idiopathic megaureter;

• ureterocele.

Image 7: Image shows the urinary bladder with no evidence of ureterocele.

The findings remained stable during the rest of the pregnancy. The neonate was delivered at 40 weeks (3950 g). Its postnatal examination found the mild left renal pyelectasis with normal parenchymal thickness and good cortico-medullary differentiation. The left ureter was not seen by ultrasonography, but cystography showed normal bladder without active or passive vesico-ureteral reflux. Following intravenous urography surprisingly discovered pyeloureteral junction obstruction inspite the prenatal good visualization of the left ureter.