Spontaneous rupture of pyelocaliceal diverticulum

One rare case of spontaneous rupture of pyelocaliceal diverticulum is reported in a 31-year-old Japanese man presented with a severe left flank pain. Intravenous pyelography and computerized tomography demonstrated extravasation of contrast medium from his diverticulum which contained numerous calculi. As a possible cause of spontaneous rupture of pyelocaliceal diverticulum in this case, we suggest that the paper-thin parenchyma covering the diverticulum was not strong enough to tolerate the minimum elevation of intrapelvic pressure due to the obstruction of delivered stones.