Antenatally Diagnosed Giant Ectopic Ureterocele Presenting with Bladder Outlet Obstruction in a Male Neonate.

A giant ectopic single-system ureterocele is an exceptionally rare congenital anomaly, particularly in male neonates. We report a case of a full-term male neonate who presented with urinary retention and metabolic acidosis shortly after birth. Antenatal ultrasonography had revealed a large intravesical cystic lesion and gross hydroureteronephrosis. Postnatal imaging confirmed a giant ureterocele prolapsing into the posterior urethra, causing bladder outlet obstruction. The patient underwent successful endoscopic deroofing with prompt resolution of symptoms. Follow-up at 6 months demonstrated improved renal drainage and stable renal function. This case underscores the clinical importance of considering ureterocele in the differential diagnosis of neonatal urinary retention and highlights the role of timely surgical intervention in preventing long-term complications.