Recurrence after percutaneous ethanol ablation of simple hepatic, renal, and splenic cysts: is it true recurrence requiring an additional treatment?

Background: Recurrence after percutaneous ethanol ablation (PEA) of benign hepatic and renal cysts has been common, resulting in re-treatment or additional surgery. However, in recent years, a few cases of spontaneous regression of recurrent cysts following PEA have been experienced, which led to the design of this study to evaluate cyst recurrence after PEA and the necessity of additional treatment. Purpose: To evaluate whether the initial recurrence after PEA of benign hepatic, renal, and splenic cysts is true recurrence, and to decide whether additional treatment is needed. Material and Methods: Thirty-nine benign cysts (21 hepatic, 17 renal, and one splenic) were treated with PEA. PEA was performed with injection of 13–900 ml (40–50% of the volume of aspirated fluid) of absolute ethanol into the cysts. For cysts larger than 100 ml, two or more PEAs were given in one session. Ultrasonography was then performed during a period of 12 months with 1–2-month intervals. Results: Two months after PEA, eight cysts (20.5%) regressed completely; another 31 cysts recurred with decreased size. After 6 months, 10 of the recurrent cysts had regressed spontaneously. Another four recurrent cysts regressed after 8 months, and three regressed after 12 months. Hence, 25 out of 39 (64.1%) cysts regressed within 12 months after PEA. The mean regression time of the 25 recurrent cysts was 6.3 months. All recurrent cysts, including the 14 that were lost to complete follow-up, showed gradual decrease overtime. There were no major complications associated with PEA. Conclusion: Initial relapse of a cyst following PEA does not signify true recurrence, but transient, reactive, or inflammatory fluid collections which eventually disappear within several months, and thus does not necessitate additional treatment.