Efficacy of Sonographically Guided Percutaneous Ethanol Injection for Treatment of Thyroid Cysts Versus Solid Thyroid Nodules

Sonographically guided percutaneous ethanol injection has been recently proposed as a treatment for nonfunctioning benign thyroid nodules such as cysts or solid nodules. The objective of this study was to compare the efficacy of ethanol injection in thyroid cysts and solid nodules. We studied 20 patients with simple or complex thyroid cysts and 22 patients with solid thyroid nodules. All lesions were confirmed by fine-needle aspiration biopsy to be benign. The mean volume of the instilled absolute ethanol (99.9%) was 62.2% of the whole tumor volume for solid nodules and 63.4% of the cystic volume for cysts. Follow-up sonography was performed 1-6 months (mean, 4.4 months for cysts and 4.6 months for solid nodules) after the procedure. The mean volume reduction rate for cysts (65%) was greater than that for solid nodules (38.3%) (p < 0.01, Student's t test). The volume of the instilled ethanol correlated significantly with the volume reduction rate of cysts but not with that of solid nodules (p < 0.01, Student's t test). Sonographically guided percutaneous ethanol injection is more effective for thyroid cysts than for solid thyroid nodules.