To compare the therapeutic results of single-session prolonged sclerotherapy to a multi-session technique in patients with renal cysts.

We reviewed 47 renal cysts of 47 patients treated by sclerotherapy. All cysts were diagnosed by ultrasonography or CT. Twenty-seven cysts (group 1) were treated by multi-session sclerotherapy, which consisted of 95% alcohol retention (20-30% of the cyst volume) for 20 minutes after aspiration of the cyst fluid, which was repeated at a 24 hour interval until the daily drained fluid decreased to 10mL. In addition, 20 cysts (group 2) were treated by single-session prolonged sclerotherapy, which consisted of one treatment session with alcohol retention (30-50% of cyst volume) for 2 hours. All patients had a follow-up ultrasonography at 3 to 6 month intervals for at least 6 months after the procedure. The therapeutic response of the treatment was classified as either a complete success (no residual cyst), partial success (diameter reduction, >50%), or failure (diameter reduction, <50%).

The complete success rates in each group were 41% and 40%, along with partial success rates of 59% and 60%. No cases of treatment failure were observed in either group. In addition, no statistical difference in the therapeutic success rate was observed between two groups (p = 0.317).

Of the two sclerotherapy techniques, we recommend the single-session prolonged sclerotherapy, considering its comparable therapeutic outcome, patient comfort and reasonable cost-effectiveness.