Giant chronic urinary retention presenting as progressive abdominal distension with a bladder volume exceeding 10 l.

Massive chronic urinary retention, particularly with volumes exceeding 10 l, is an exceptional manifestation of bladder outlet obstruction (BOO) and may remain undetected until complications arise. We present the case of a 55-year-old who developed progressive abdominal distension with minimal lower urinary symptoms. Ultrasonography demonstrated a markedly enlarged bladder with a volume exceeding 10 l and bilateral hydroureteronephrosis. Following emergency referral, urethral catheterization drained 9.8 l and was followed by significant post-obstructive diuresis requiring monitoring and intravenous fluid replacement. Despite extensive radiological changes, renal impairment was relatively mild. Further evaluation identified a 28 ml prostate, and transurethral resection of the prostate (TURP) histology confirmed benign prostatic hyperplasia (BPH). This case highlights the remarkable compensatory capacity of the urinary tract in chronic obstruction and reinforces the importance of early recognition, close monitoring, and definitive management of BOO. Long-term bladder function remains under assessment because of suspected detrusor underactivity.