Bethesda System for Reporting Thyroid Cytopathology in Pediatric Thyroid Nodules: Experience of a Tertiary Care Referral Center

Abstract

Context.— The Management Guidelines for Children with Thyroid Nodules and Differentiated Thyroid Cancer from The American Thyroid Association recommends fine-needle aspiration (FNA) as an essential tool for evaluation and management of pediatric thyroid nodules, and The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) as a guideline to categorize FNA cytologic findings. A few publications have focused on TBSRTC categorization in children. Objective.— To evaluate our institutional experience of using TBSRTC in the pediatric population. Design.— We conducted a retrospective data search for thyroid FNA specimens from patients younger than 21 years who were assessed by using TBSRTC categorization between January 1, 2011, and September 30, 2017. Cytologic and histologic diagnoses, rate of surgical follow-up, rate of histology-proven malignancy, and cytologic-histologic concordance were assessed in comparison with our previously published adult experience. Results.— Among a total of 201 specimens, benign category accounted for 103 (51.2%), followed by 35 (17.4%) malignant, 30 (14.9%) atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 14 (7.0%) nondiagnostic, 10 (5.0%) follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), and 9 (4.5%) suspicious for malignancy (SFM) categories. Surgeries were subsequently performed in 100 of the 201 cases (49.8%). All surgically removed nodules categorized as malignant and SFM by FNA showed malignancy, while malignancy was evident in various proportions of specimens classified as AUS/FLUS (5 of 16; 31.3%), FN/SFN (1 of 9; 11.1%), and nondiagnostic (1 of 7; 14.2%). No malignancy was identified in the benign category. Cytologic-histologic concordance achieved 100% in malignant, SFM, and FN/SFN categories, and exceeded beyond 85% and 50% for benign and AUS/FLUS categories, respectively. Conclusions.— TBSRTC is effective for appropriate categorization of pediatric thyroid nodules. Risk of malignancy in thyroid nodules is higher for the pediatric than adult population. Understanding the difference in TBSRTC categorization between children and adults may aid in achieving more appropriate evaluation and management of pediatric thyroid nodules.