Two Decades of Thyroid Nodule Cytology in Children: Malignancy Risk Assessment at a Tertiary Care Center

Abstract

Introduction: Pediatric thyroid nodules exhibit higher malignancy rates compared to adults and are associated with increased incidences of metastases and recurrences. The American Thyroid Association recommends surgery for indeterminate thyroid biopsies in children based on these higher malignancy risks, though this approach may lead to overtreatment. However, there remains a lack of comprehensive pediatric data to inform clinical decisions. This study examines the risk of malignancy (ROM) in pediatric thyroid nodules using the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) and assesses the diagnostic accuracy of fine-needle aspiration biopsy (FNA) compared to histological outcomes. Methods: A retrospective cross-sectional analysis was performed on patients under 19 years with thyroid nodules who underwent FNA and thyroidectomy at a tertiary care center. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and ROM of cytological biopsies were evaluated using TBSRTC criteria, with histology serving as the gold standard. Two analyses were conducted to assess diagnostic accuracy: (a) TBSRTC II as negative and TBSRTC VI as positive, and (b) TBSRTC II as negative with TBSRTC V and VI as positive. For neoplasia detection, TBSRTC II was deemed negative, while TBSRTC IV, V, and VI were considered positive. TBSRTC categories III and I were excluded from the performance analysis and evaluated separately. Follicular neoplasm or lesions suspicious for follicular neoplasm (FN/SFN) were treated as positive outcomes, correlated with the presence of adenoma or carcinoma in the surgical specimen. Results: Of 75 nodules from 73 patients, 28 (37.3%) were benign and 47 (62.6%) malignant. No significant differences in gender or age were noted between groups. The ROM in each TBSRTC were Bethesda I 0/2, 0%; II 0/13, 0%; III 2/7, 29%: IV 6/14, 43%; V 10/10, 100%, and VI 29/29, 100%, respectively. A sensitivity of 78.38% and specificity of 100% for FNA in detecting malignancy was found, with an even higher sensitivity (100%) for detecting neoplasia in TBSRTC IV. Conclusions: This study reveals that indeterminate thyroid nodules in pediatric patients exhibit a higher rate of malignancy compared to adults, yet align with rates previously reported in the pediatric population. These findings highlight the critical need for guidelines tailored specifically to the management of thyroid nodules and thyroid cancer in children.