Urinary Bladder Diverticulum Presenting as a Palpable Abdominal Mass in a Neonate: A Case Report

Congenital Bladder Diverticulum (CBD) is a rare neonatal anomaly that typically presents with urinary tract infections, haematuria, or voiding dysfunction. However, it can occasionally present as an abdominal or suprapubic mass, which is an uncommon manifestation in the absence of urinary symptoms. This case report describes a full-term female neonate born at 39 weeks whose antenatal ultrasound revealed an abdominopelvic cyst. Postnatal MRI demonstrated a large, wide-necked diverticulum (3.3×3.9×2.8 cm) arising from the right superolateral wall of the bladder, extending into the right iliac fossa. The infant remained asymptomatic with respect to urinary symptoms, with normal urine output and no infection. Conservative management was undertaken, involving regular ultrasonographic monitoring and a planned Micturating Cystourethrogram (MCU). Over a six-month follow-up period, there was no increase in the size of the diverticulum, no evidence of vesicoureteral reflux, and preserved renal function. This case report underscores that in neonates, bladder diverticulum can present as a cystic abdominal mass even in the absence of classic urinary signs. Early anatomical imaging and longitudinal follow-up are crucial for identifying potential complications and guiding appropriate management. This case highlights the importance of considering congenital bladder anomalies in the differential diagnosis of neonatal abdominal cysts, even when urinary symptoms are absent.