Ultrasound-guided percutaneous ethanol injection of small and medium-sized thyroid cysts with relatively small amounts of ethanol

BACKGROUND: Ultrasound-guided percutaneous ethanol injection (US-guided PEI) is used in patients with recurring symptomatic thyroid cysts in whom simple drainage was not successful. It is an alternative non-surgical approach in patients refusing or at risk during surgery. METHODS AND RESULTS: US-guided PEI was performed in 33 patients, with a success rate of 100% and significantly decreased cyst volume after 1, 3 and 6 months after the last PEI compared with the initial volume. The mean number of PEI procedures was 1.5±0.7 with a mean 96% ethanol volume of 2.4±1.2 mL. In the entire group, the initial cyst volume was significantly reduced to the final volume at 6 months after PEI (10.82±5.03 mL vs. 0.78±0.84 mL; P<0.001). Also in all patients, mean volume reduction rates were significantly increased (P<0.001) at check-ups at 1 month (83.1±8.1%), 3 months (89.9±6.3%) and 6 months (92.6±6.4%). In case of medium-sized cysts, more PEI procedures were needed than in small cysts (1.1±0.4 vs. 2.0±0.5). The total amount of 96% ethanol was equal to 22.7±7.9% of the initial cyst volume. CONCLUSION: Our experiences confirm that small and medium-sized cysts may be successfully treated with relatively small amounts of ethanol. In case of medium-sized cysts, more PEI procedures were needed. Final reduction of complex cysts was achieved later. Apart from temporary localized pain, no serious complications were observed in most cases.