Massive congenital bladder diverticulum in a teenager: Navigating an uncommon clinical entity through an exceptional therapeutic challenge - A case report.

Primary congenital bladder diverticula, rare in pediatric populations and particularly in females, often justify surgery for symptomatic cases. We report a 15-year-old girl with a giant bladder diverticulum, significant post-void residual urine, and preserved renal function without vesicoureteral reflux. Conservative care included antibiotic prophylaxis, surveillance imaging, and lifestyle modifications was adopted due to family refusal of surgery. Clinical stability (reduced infections, no complications) and anatomical stability were observed, supporting the hypothesis of residual muscular fibers as a stabilizing factor, suggesting potential nosological reclassification. This case underscores individualized therapeutic decisions integrating family preferences and rigorous monitoring.