A case of a transplanted kidney with an orthotopic kidney stone.

A 39-year-old man was admitted to our hospital with kidney stones after kidney transplantation. Kidney, ureter, and bladder radiographs showed multiple stones in the transplanted and orthotopic kidneys, which had not been reported previously. Owing to the larger size of the stones in the transplanted kidney, they needed to be removed. Percutaneous nephrolithotomy and ureteroscopy were performed under B-mode ultrasound guidance. The stone measured 1.9 × 1.6 cm and was located under the calyx of the kidney. A titanium laser fiber was used to dissolve the stones, which were subsequently removed. No adverse reactions occurred during or after the surgery. The causes of stone formation included dietary factors, related drugs, improper fluid intake, and urinary tract infections. As neither the donor nor the recipient had a history of kidney stones, we hypothesized that the stones were a new entity that either developed following transplantation or a long-term complication.