The role of thyroid fine-needle aspiration cytology in the pediatric population: an institutional experience.

BACKGROUND: The current study was conducted to investigate the role of thyroid fine-needle aspiration cytology (FNAC) in the authors' pediatric series. Thyroid pediatric FNAC has been reported to have conflicting sensitivity and specificity in different series. The authors evaluated their thyroid cytological series mainly for the categories of 1) follicular/indeterminate neoplasms with atypical cells of indeterminate significance (FN/AUS) and 2) suspicious for malignancy (SM). In this setting, the application of immunocytochemistry (ICC) is likely to allow a correct diagnosis.

METHODS: A total of 64 of 247 pediatric FNACs (26%) that were processed with liquid-based cytology had surgical follow-up. An ICC panel (Hector Battifora mesothelial cell-1 [HBME-1] and galectin-3) was performed on liquid-based cytology. A positive immunopanel was defined by a concordant positivity.

RESULTS: These 64 cases were cytologically diagnosed as 4 cases of cystic hemorrhagic lesions, 23 benign lesions (BL), 17 FN/AUS cases, 11 SM cases, and 9 positive for malignancy (PM) cases. All PM and BL cases were histologically confirmed. The rate of malignancy was 31.2%, including 1 case of follicular carcinoma, 9 cases of classic papillary thyroid carcinomas (PTC), and 10 PTC variants (7 follicular variant of PTC, 1 macrofollicular variant, and 2 sclerosing diffuse variants). The immunopanel was performed on the categories of FN/AUS, SM, and PM. The data highlighted a concordant positive ICC in 87% of malignancies and a concordant negative ICC in 100% of benign follicular adenomas.

CONCLUSIONS: Thyroid FNAC represents a valuable/feasible tool in childhood. The higher incidence of histological malignancies justifies the cytological application of ancillary techniques (ie, ICC or molecular panels), thereby enabling a more adequate surgical selection based on the effective distinction of high-risk and low-risk lesions mainly for the categories of FN/AUS and SM.