Case Report: Pseudo-prune belly syndrome after early fetal bladder decompression: implications for the pathogenesis of prune belly spectrum disorders.

Abstract

Background: Prune Belly Syndrome (PBS) is a rare congenital disorder characterized by abdominal wall deficiency, urinary tract dilatation, and bilateral cryptorchidism. Its pathogenesis remains controversial, with both developmental and mechanical theories proposed. Whether early fetal decompression influences the phenotypic expression of PBS has not been established.

Case presentation: We report a male fetus diagnosed at 12 weeks' gestation with severe megacystis and bilateral hydroureteronephrosis. A Somatex^® vesicoamniotic shunt was placed at 16 weeks because of progressive lower urinary tract obstruction. Prenatal follow-up demonstrated complete resolution of upper urinary tract dilatation and persistent bladder decompression throughout pregnancy. After birth, the patient presented bilateral cryptorchidism and mild abdominal wall weakness but preserved renal morphology and function. Voiding cystourethrography showed high-grade bilateral vesicoureteral reflux, and diagnostic cystoscopy excluded posterior urethral valves and urethral atresia, supporting the diagnosis of Pseudo-Prune Belly Syndrome (PPBS). At 6 months of follow-up, the patient remains asymptomatic, with no urinary tract infections, spontaneous bilateral testicular descent, stable abdominal wall weakness, normal renal growth, and preserved renal function.

Conclusion: This case illustrates a favorable early outcome following prenatal vesicoamniotic shunting in a fetus with severe lower urinary tract obstruction who subsequently developed an attenuated phenotype consistent with PPBS. Although causality cannot be inferred from a single observation, these findings are consistent with the fetal outlet obstruction hypothesis and raise the possibility that early fetal decompression may influence phenotypic expression in selected patients. Further studies are required to clarify the role of prenatal intervention in the pathogenesis and clinical spectrum of PBS.