Usefulness of ultrasound-guided fine-needle aspiration cytology in the diagnosis of non-palpable small thyroid nodules

Aims and background. Diverse and contradictory approaches have been suggested for the management of non-palpable thyroid nodules. The aim of our study was to evaluate the indications and limits of ultrasound-guided fine-needle aspiration cytology (US-FNAC) in non-palpable infracentimetric thyroid nodules. Methods and study design: From September 2003 to December 2004 we observed 325 patients with non-palpable thyroid nodules. We divided our series into three groups according to the diameter of the lesion in order to verify the effectiveness of US-FNAC for lesions of less than 1 cm. Results: We assessed the cases with satisfactory and unsatisfactory results in the three groups into which the sample was divided (4 mm to 1 cm; 10.1 mm to 15 mm, and 15.1 mm to 25.5 mm). Our statistical analysis by means of the z-test showed there was no significant (5%) difference in the percentage distribution of the unsatisfactory results in the three groups. Conclusions: Fine-needle cytology appears to be a useful diagnostic tool also for nodules of less than one cm because the percentage of unsatisfactory results is not related to the size of the nodule.