Treatment of simple renal cysts by percutaneous aspiration and OK-432 sclerotherapy

Purpose: Percutaneous aspiration with sclerotherapy has been widely used for the treatment of symptomatic or large simple renal cysts. Ethanol has been most commonly used as a sclerosing agent; however, a temporary percutaneous nephrostomy for multiple ethanol injections is necessary to achieve a low recurrence rate. Thus, we used OK-432 as a new sclerosing agent without a temporary percutaneous nephrostomy for multiple injections, and also compared our results with the results of previous studies. Materials and Methods: Between October 2005 and April 2006, 50 patients (63 simple renal cysts) who underwent percutaneous OK-432 sclerotherapy for simple renal cysts were evaluated. The simple renal cysts were aspirated under ultrasonography and fluoroscopy, after which OK-432 was injected into the cyst. Follow-up was performed with ultrasonography or CT scan after 3 months. Regression of the renal cyst or a >70% reduction in size with no symptoms was considered a treatment success. Results: Among 63 renal cysts in 50 patients, complete regression occurred in 17 (27.0%). Greater than a 90% reduction in size occurred in 8 (12.7%), a 80-90% reduction in size occurred in 21 (33.3%), and a 70-80% reduction in size occurred in 15 (23.8 %); a <70 % reduction in size occurred in 2 (3%). The overall efficacies of success were 96.8%. After the procedure, there were only some minor complications, such as mild fever, local pain, and liver function test elevation that subsided with symptomatic treatment. Conclusions: Percutaneous OK-432 sclerotherapy is simple, safe, and effective and can be an alternative first-line therapy of simple renal cysts.