A large unilateral contained urinoma in a fetus: an indication for intrauterine urinary shunting.

A large contained urinoma measuring 12 x 8 x 8 cm3 was diagnosed in the left kidney of a female fetus at 28 weeks gestation. Analysis of fluid from serial punctures of the cyst indicated that renal function on that side was poor, but because ultrasound findings of the thorax suggested lung growth impairment, a shunt was inserted. After 3 weeks the shunt dislocated into the fetal abdominal cavity and urinous ascites developed. The ascites was found to have resolved spontaneously on ultrasonography 3 weeks later. The infant was delivered at 37 weeks gestation and appeared normal except for bilateral pelvi-ureteric obstruction. This was much worse in the left kidney, the renal function of which was only 10% of normal. A left nephrectomy was carried out when the infant was 6 months old, when the inner part of the shunt was discovered in perinephric fibrous tissue. The renal pelvis was greatly enlarged and fibrotic; no site of rupture could be identified. The infant's respiratory function was normal. This case suggests the use of intrauterine shunting to decompress a large unilateral urinoma resulting in marked elevation of the fetal diaphragm to prevent impairment of fetal lung growth.