Introduction: The aim of this study was to find the ultrasound (US) features which can be helpful in selecting small thyroid lesions for fine needle aspiration biopsy (FNAB).
Materials and methods: The outcomes were analyzed of US examinations, FNABs, and postoperative histopathological examinations performed during the years 2000-2005. The occurrence of small lesions of the thyroid revealed by US was assessed. Then, palpability and several US features of those lesions were evaluated, like the total echogenicity, the pattern of vascularisation, the presence of microcalcifications and coexistence with other lesions in the goitre. Those features were correlated with the results of histopathological examinations. Altogether 356 lesions found in 284 patients were analyzed, of which 315 were non-neoplastic lesions, 12 - follicular neoplasms, and 29 - thyroid carcinomas.
Results: The small thyroid lesions were revealed in 53.8% patients examined by US. The detailed analysis of US outcomes and the postoperative histopathological examinations showed that carcinomas with diameter ≤ 10 mm when compared with small benign lesions presented more frequently as solitary lesions (48.2% vs. 16.2%; p < 0.001), hypoechoic (72.5% vs. 45.6%; p < 0.01) and with microcalcifications (10.3% vs. 1.5%; p < 0.01). Moreover, carcinomas with extrathyroidal invasion were hypoechoic more frequently than the other carcinomas (90.0% vs. 36.8%; p < 0.05).
Conclusions: The obtained results show the necessity for the limitation of number of performed biopsies in case of small thyroid lesions. They also provide rationale for consideration of some US features (like lowered echogenicity, the presence of microcalcifications or other lesions in the goitre) during selection of lesions to FNAB.