Spontaneous Communication between a Simple Renal Cyst and the Pyelocaliceal System with a Gas-Producing Infection

We present the extremely rare case of a 44-year-old woman who presented with right flank pain and high fever, which proved to be a case of spontaneous communication between a renal cyst and the pyelocaliceal system caused by increased pressure in the renal pelvic cavity exerted by a stone leading to infection.