Treatment of simple renal cysts by percutaneous puncture and instillation of bismuth-phosphate.

One hundred and fifty-six patients with simple renal cysts had either a percutaneous puncture alone, percutaneous puncture combined with bismuth-phosphate instillation or no intervention at all. At follow-up, 25% of the cysts in which there was no intervention had grown and the mean size showed a slight increase. Ten per cent of the cysts which were only percutaneously punctured disappeared, while the mean size was reduced up to 24 months after puncture. Later, there was no statistically significant difference in change in mean size between punctured cysts and cysts that had no intervention. When puncture was combined with bismuth-phosphate instillation, a gradual reduction was seen in the mean size during the entire follow-up time and 44% of the cysts disappeared. Thirty-six or more months after puncture and instillation, the mean size was only 21% of the original size. It was concluded that percutaneous puncture combined with a bismuth-phosphate instillation is a meaningful treatment of simple renal cysts.