[An unusual variant of intrarenal refluxes in the renal sinus cyst].

The intrarenal reflux is caused by impaired emptying of the renal pelvis, that leads to increased intrarenal pressure. Increased pelvis pressure can be the result of a variety of states. The most common causes are acute upper urinary tract obstruction or overfilling of the pelvis during retrograde intrarenal surgery (RIRS) or retrograde pyelography. In rare cases, it is due to impaired neuromuscular tone of the upper urinary tract that leads to hyperkinetic state. We have presented case with a 73-year-old patient with intrarenal reflux into the peripelvic renal cysts. Since no such cases were found in the literature, this observation is unique.