Fetal urinary ascites caused by bladder rupture due to paraurethral cyst: a rare case.

Fetal urinary ascites is an uncommon prenatal finding most often associated with lower urinary tract obstruction (LUTO). We report a rare case of fetal urinary ascites caused by bladder rupture secondary to suspected urethral compression by a paraurethral cyst. A 26-year-old gravida 3 para 1 woman was referred at 32 weeks' gestation due to newly detected isolated fetal ascites and mild polyhydramnios. Detailed ultrasonography suggested bladder wall defect and a cystic structure adjacent to the right inguinal canal. Fetal MRI confirmed bladder rupture and supported the suspicion of LUTO. Conservative management was adopted due to stable fetal condition and preserved renal appearance. The ascites resolved spontaneously before delivery. A healthy female neonate was born at term, and the paraurethral cyst resolved spontaneously postnatally. This case highlights a rare etiology of fetal urinary ascites and demonstrates that expectant management may result in favorable outcomes in selected cases.