Prenatal sonographic monitoring of idiopathic megacystis.

This case report is of a female fetus diagnosed with severe idiopathic megacystis at 21 weeks of pregnancy. Sonographic monitoring demonstrated normal amniotic fluid volume and renal structures, absence of hydronephrosis, ureteral dilation, and associated abnormalities. Conservative management was chosen with postnatal confirmation of diagnosis. The neonate presented seizures, and subsequent magnetic resonance imaging demonstrated transverse sinus thrombosis with adjacent ischemic damage. At present, the infant is 2 years old, and she is thriving normally and maintains urinary continence with spontaneous voidings.