Development of multiple calculi in the duplex system ureterocele.

A 61-year-old man presented complaining of pollakisuria and nocturia. A plain radiograph of his kidney, ureter and bladder and intravenous urography revealed numerous calculi in the upper kidney of his left renal pelvis and ureterocele. A transurethral incision of ureterocele (TUI-ureterocele) and extracorporeal shock wave lithotripsy were performed. On TUI-ureterocele, the many calculi were found to be almost the same size and spherical in form. The postoperative clinical course was uneventful.