A Large Unilateral Contained Urinoma in a Fetus: An Indication for Intrauterine Urinary Shunting

Abstract

A large contained urinoma measuring 12 × 8 × 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.

Enlarged fetal bladder: Differential diagnosis and outcomes

“…5 A rupture of the urinary tract with subsequent urinoma, as occurred in this case, is very rare, and only a few cases have been reported in the literature. 6 In Case 2, a neurogenic bladder ruptured, subsequently leading to urinary ascites. This is also a very rare event.…”

Fetal urinoma and prenatal hydronephrosis: how is renal function affected?

“…In addition, puncturing a urinoma has no effect on renal function prognosis. [18] In our study, none of the patients required puncture of a urinoma during the prenatal follow-up.…”

Fetal urinoma as a sign of a dysplastic kidney

“…The 12th case was shown postnatally to have a hypoplastic kidney [6]. Of note, a decrease in size of the urinoma occurring either spontaneously [3,6] or following in utero decompression [7,8] did not favorably influence the impaired function of the affected kidney. It follows, therefore, that the visualization of a prenatal urinoma is probably a sign of underlying renal dysplasia.…”

“…Urinoma must first be differentiated from hydronephrosis. Although, in the latter condition, the dilated renal pelvis is usually surrounded by renal parenchyma, due to compression and displacement of the intra-abdominal organs by the mass, identification of the kidneys may be precluded [8]. Thereafter, other causes of a retroperitoneal cystic mass, such as lymphangioma, hemorrhagic neuroblastoma, mesenteric cyst, enteric duplication, and other cystic renal diseases, namely multicystic kidney, polycystic kidney disease, and Wilms tumor, have to be excluded.…”