Endoscopic ultrasound-guided ethanol lavage as a novel therapeutic modality for symptomatic simple renal cysts

EUS-guided ethanol lavage (EUS-EL) has not been evaluated for the treatment of symptomatic simple renal cysts. This study aimed to assess the feasibility, safety, and efficacy of EUS-EL.

In this pilot study conducted at a single center from March 2018 to October 2024, patients with radiologically confirmed simple renal cysts and relevant clinical indications underwent EUS-EL. We used a 19-gauge needle to aspirate cyst fluid under real-time EUS guidance and replaced it with 99% ethanol. Treatment outcomes included technical success, volume reduction on follow-up imaging, and adverse events (AEs).

Fourteen patients with 20 renal cysts were enrolled. Most cysts were located in the left kidney (75%). The median baseline cyst volume was 127.0 mL (IQR, 63.4-215.1 mL), which decreased to 4.4 mL (IQR, 0.9-9.6 mL) at final follow-up, with a median volume reduction of 96.3%. Complete resolution (≥95% volume reduction) was achieved in 13 cysts (65.0%), partial resolution was achieved in 6 (30.0%), and 1 cyst (5.0%) showed persistent volume. Technical success was 100%, and no major AEs occurred. One patient (7.1%) experienced a minor AE that was self-limiting.

EUS-EL appears technically feasible and safe for treating simple renal cysts, with preliminary results supporting further evaluation in larger prospective studies.