Cold benign thyroid nodule volume reduction predictability after percutaneous ethanol injection

Objective: To determine the effect of percutaneous ethanol injection (PEI), a suppressive therapy for cold benign thyroid nodules (CBNs), on cytology. Study Design: The study group consisted of 31 CBNs, treated with PEI for 1 year, aspirated before and while the patients were on suppressive therapy. A control group consisting of 22 patients, whose nodule characteristic, PEI treatment and follow-up were similar to those of the study patients group, was monitored to confirm the results. By analogy with a similar study, the following factors were considered: an initial volume of the CBNs > 25 mL, abundant colloid, degree of cellular hyperplasia and presence of degenerative changes. To verify these hypotheses, we tested the differences using the t test for the initial volume and the Mann-Whitney U test for the remaining features. Results: The study has proved the unpredictability of the volume reduction in a single nodule on the basis of cytologic evaluation. Conclusion: The lack of cytologic features that can be considered statistically predictive of large nodule reduction as a result of PEI treatment confirms that fine needle aspiration cytology may help establish the correct diagnosis.