Xanthine stone in the urinary bladder of a male child.

Urinary tract calculi composed primarily of xanthine are rate both in adults and children. We describe the clinical presentation and management of a 3.5-year-old boy with hereditary xanthinuria (an autosomal recessive disorder of purine metabolism) and primary bladder calculus formed from xanthine. To our knowledge this case demonstrates a previously undescribed form of xanthinuria in childhood. Xanthine stones, although rare, should be considered in the diagnosis of urolithiasis.