Solitary cyst of fetal kidney:

This 2nd trimester fetus shows a solitary cyst of the lower pole of left fetal kidney. The cyst is small (6 mm.) with no internal debris or septae. The fetal renal cyst shows no communication withe the pelvicalyces which appear norma, thus ruling out fetal hydronephrosis. The fetal urinary bladder (BL) appears normal. The above ultrasound images are typical of uncomplicated cyst of the fetal left kidney. The important differential diagnoses in this case include renal abscess or renal hematoma, both of which seem improbable here. The other possibility is that this cyst is precursor to onset of autosomal dominant polycystic kidney disease (adult type). Polycystic kidney disease may develop in this baby during adult life. Both images are courtesy of        Dr. Ravi Kadasne, MD, UAE.
For more on this topic visit: http://www.ultrasound-images.com/fetal-urogenital.htm