Abstract 183: Ultrasound Guided Percutaneous ethanol injection (PEI) for the treatment of cystic and predominantly cystic thyroid nodules: A single center experience

Objective: To determine the efficacy and safety of percutaneous ethanol injection (PEI) for the treatment of cystic and predominantly cystic thyroid nodules. Materials and Methods: Retrospective analysis was performed of 35 patients with cystic and predominantly cystic (>50%) thyroid nodules who were treated using ultrasound guided percutaneous ethanol injection between January 2020 to April 2022. All patients underwent fine needle aspiration (FNA) of their cyst demonstrating benign pathology (Bethesda II). The main outcomes were efficacy, defined as reduction in nodule volume of 50% or more, and safety, defined as no or minor adverse events. Patients were assessed at post-procedure months 1, 3, 6, and 12. Results: 35 patients underwent ultrasound guided percutaneous ethanol injection (PEI) for the treatment of cystic and predominantly cystic thyroid nodules. 32 patients were female and 3 patients were male. Mean age was 35.6 years (range 19 to 56 years). All patients were euthyroid. The median largest diameter of the thyroid nodule was 4.5 cm (range, 3.2-8.0 cm); the median volume pre-PEI was 16.6 mL (range, 2.6-108.1 mL). All patients had a 50% or greater reduction in nodule volume. The median final volume on last follow-up ultrasound was 3.98 mL (range, 0.32-40 mL), and median volume reduction was 76% (range,0%-97%). 3 patients had recurrence. There were no significant adverse effects and the procedure was well tolerated by all patients. Adverse effects occurred in 4 patients (20%) and were mild and temporary (pain and bleeding into the cyst). The pericapsular infiltration with xylocaine before the procedure could be the reason for less pain during and post procedure. The injected ethanol was not reaspirated and it could be the reason for greater volume reduction in this study. [INLINE:1] Conclusion: Percutaneous ethanol injection (PEI) appears to be a safe and effective alternative to surgical resection for patients with benign cystic and predominantly cystic thyroid nodules.