Urinary bladder agenesis presenting with bilateral pelviureteric junction obstruction in an infant: a rare urological anomaly.

Urinary bladder agenesis is an extraordinarily rare congenital anomaly, often associated with complex genitourinary malformations and poses significant diagnostic challenges in infancy. We report an infant girl with progressive abdominal distension, continuous urinary dribbling and bilateral hydronephrosis, ultimately found to have bladder agenesis with bilateral pelviureteric junction obstruction, ectopic ureteric insertion into the vagina and malrotated kidneys. Multimodality imaging, including ultrasonography, radionuclide diuretic renography with single-photon emission CT/CT and contrast-enhanced CT, was essential for establishing the diagnosis when the bladder was not visualised on initial evaluation. The child underwent staged management with initial decompression by percutaneous nephrostomy followed by left pyeloplasty, and was planned for delayed bladder reconstruction, but was lost to follow-up. This case highlights the need for high index of suspicion when the bladder is not visualised on imaging in infants with continuous dribbling and upper tract dilatation. It underscores the need to prioritise relief of obstruction before definitive reconstruction.