Thyroid Fine Needle Aspiration Biopsies in Children: Study of Cytological-Histological Correlation and Immunostaining with Thyroid Peroxidase Monoclonal Antibodies

The prevalence of thyroid nodules in adults is well established through large population-based studies, with a reported range of 3.2% to 8% [1]. In children, thyroid nodules are less frequently detected than in adults and sources quote a prevalence of 1.5% [2]. However, the rate of malignancy in operated pediatric thyroid nodules is higher than in adults, varying from 9.2% to 50% [3–7]. As a consequence, there is increased anxiety for malignancy in childhood thyroid nodules and a more aggressive treatment approach has been suggested for any nodule discovered in childhood.Fine-needle aspiration biopsy (FNAB) is currently considered the most effective technique for morphological diagnosis of thyroid nodules. Traditionally, FNAB results are divided into four categories: inadequate or nondiagnostic, benign, indeterminate (otherwise described as suspicious for neoplasm), and malignant [8]. High diagnostic accuracy of FNAB was reported in cases of benign and malignant cytology. However, the suspicious FNABs are problematic with 10% to 60% of these lesions proven to be malignant after histological examination. In recent recommendation of Papanicolaou Society of Cytopathology, suspicious FNABs were subcategorized into three groups: indeterminate, follicular neoplasms, and suspect of carcinoma [9]. In a large study including 4703 FNABs, the rates of malignancy in operated indeterminate, follicular neoplasms, and suspect of carcinoma FNAB were 13.5%, 32.2%, and 64.7%, respectively [10].A number of new techniques have been investigated in order to improve the accuracy of FNAB. These techniques attempt to take advantages of differences in genetic, molecular, and biochemical signatures between benign and malignant thyroid lesions to identify reliable malignancy markers. Some markers, such as thyroid peroxidase, dipeptidyl-aminopeptidase IV (DPPIV), and Hector Battifora mesothelial antigen-1 (HBMA-1) were shown to be strongly correlated with thyroid cancer progression and are con