A huge bladder calculus causing acute renal failure

We present a 39-year-old man with repeated urinary tract infection and lower abdominal pain. Kidney–ureter–bladder (KUB) and IVU film showed a huge 450-g elliptical pelvic calculus that was surgically removed with excellent results. Surgical intervention by cystolithotomy or endoscopic cystolithotripsy can achieve satisfactory results. Bladder outlet obstruction should be treated simultaneously. Bladder stone is a common disease, but it is rare for such a calculus to be so large as to cause bilateral hydronephrosis. Close follow-up, however, is mandatory because the recurrence of urolithiasis is high in those patients with voiding problems and recurrent urinary infection. To the best of our knowledge, this is the largest bladder stone in a human male.