A case history of a foreign body stone in the urinary bladder.

A case of a foreign body stone which formed on an indwelling catheter that was left in the urinary bladder for a long time is described. Foreign body stones are composed primarily of a mixture of struvite and carbonate apatite, which are components of infection stones. The foreign body can be iatrogenic, accidentally or self-induced, or endogenous, suggesting that a variety of materials can serve as the nucleus for the stone.