ROLE OF ULTRASOUND-GUIDED FINE-NEEDLE ASPIRATION BIOPSY IN EVALUATIONOF NONPALPABLE THYROID-NODULES

To determine the role of ultrasound-guided fine-needle aspiration biop sy (US-FNAB) in the evaluation of incidentally diagnosed nonpalpable t hyroid nodules (NP-TN), we compared the diagnostic yield of US-FNAB in NP-TN larger than 10 mm in diameter, with palpation-guided (P-FNAB) i n palpable thyroid nodules (P-TN) in the same hospital setting. Of 108 consecutive patients with NP-TN (female/male: 97/11, age: 55.2 +/- 14 ,3, mean +/- SD), malignancy was identified in 8 patients (7 with thyr oid papillary carcinoma, 4 of which had extrathyroidal spread, and 1 p atient had metastasis of pulmonary adenocarcinoma). Male gender was as sociated with higher prevalence of malignancy (p = 0.09) while calcifi cation and/or cystic degeneration of the nodule did not predict the cy tological findings. Malignancy was identified in 16 of 151 consecutive patients with P-TN (female/male: 139/12, age: 44.1 +/- 9.5, mean +/- SD) indicating a similar rate of malignancy in both NP-TN and P-TN. In the P-TN group thyroid cancer was more common in males (p = 0.007), a nd the US properties of the nodule did not predict its cytological dia gnosis. In conclusion, because similar rates of cancer are detected by FNAB in both NP-TN and P-TN, an FNAB is recommended for NP-TN larger than 10 mm.