Clinical Experience of Single-Session Percutaneous Aspiration and OK-432 Sclerotherapy for Treatment of Simple Renal Cysts: 1-Year Follow-Up

Purpose: To evaluate the efficacy and safety of single-session OK-432 sclerotherapy for the treatment of renal cysts. Materials and Methods: From October 2005 to November 2006, 48 patients (61 simple renal cysts) were included in the study. Indications were determined as flank discomfort (n = 37) or patient reassurance due to increasing size (n - 11). The simple renal cysts were aspirated under ultrasonography (US), at which point OK-432 was injected into the cyst. Follow-up was performed with US or computed tomography scan every 3 months until 1 year. Complete regression of the renal cyst or more than 70% reduction in size with no symptoms indicated a successful treatment. Results: Among 61 renal cysts of 48 patients, the overall success rate was 98.4%. Complete regression occurred in 46 cysts (75.4%), and more than 90% reduction in size occurred in 6 cysts (9.8%). A size reduction of 80% to 90% and 70% to 80% occurred in five (8.2%) and three cysts (4.9%), respectively. A size reduction less than 70% occurred in only one cyst (1.6%). The success of cyst regression was correlated with cyst volume. Clinical symptoms resolved in 100% of patients with symptomatic cysts, and there was no enlargement of the aspirated cysts at the 1-year follow-up. After the procedure, there were only some minor complications, such as mild fever, flank pain, and leukocytosis, which subsided with the conservative treatment. Conclusions: Percutaneous OK-432 sclerotherapy is simple, safe, and effective, and it can be an alternative first-line therapy for simple renal cysts.