Clinical, Radiologic and Cytologic Predictors of Malignancy in Pediatric Thyroid Nodules: Insights From a 26-Year...

Thyroid nodules are less common but more often malignant in pediatric patients than in adults. Our objectives were to study the features of benign vs. malignant thyroid nodules in a large pediatric patient cohort.

Retrospective observational cohort study. Consecutive patients aged 0.01-17.9 years at evaluation between 1997-2023 for thyroid nodules larger than 0.5 cm recruited at the endocrinology department of Necker Children's University hospital in Paris, France, were included. The main outcome measures concerned the benign or malignant nature of the nodules. The diagnostic accuracy of fine-needle aspiration biopsy (FNAB) was assessed, as well as the treatments used.

We studied 153 patients, 112 (73%) of them were female. Mean age at diagnosis was 12.6 years (0.01-17.9). Malignant nodules were identified more rapidly (0.65 years) than benign (1.25 years) lesions (p = 0.03). The overall malignancy rate was 17% (26/153). Median largest nodule diameter was 13.1 (8-27) mm; diameter was < 10 mm for 23% of malignant nodules. FNAB was performed in 82/153 cases (53.6%) and was associated with larger nodule size (p < 0.001) and history of radiation exposure. Autoimmune thyroiditis was present in 19% (4/21) of malignant nodules. By univariate analysis, significant predictors of malignancy were radiation exposure (p = 0.032), calcifications (p = 0.022), and lymph node involvement (p = 0.019). None of these variables was substantial by multivariate analysis.

Nodule size, ultrasound characteristics, and FNAB findings alone were insufficient to reliably detect malignancy. Increased vigilance is warranted for subcentimeter nodules and those with autoimmune thyroiditis. Close long-term follow-up is advised even in cases with benign cytology.