Indiana pouch stone formation caused by a long-forgotten metallic ball bearing.

The presence of a foreign body in the urinary tract may serve as a nidus for stone formation. A 40-year-old male was found on CT scan to have a 2.4 cm stone in his Indiana pouch urinary diversion. As the stone was fragmented during endoscopic lithotripsy, a metallic round object was visualized, which was subsequently established to be a metallic ball bearing. Upon questioning after the procedure, the patient reported that 4 years earlier he had been accidentally shot with a blow dart gun and the "miraculous hit" went directly into his Indiana pouch stoma.