Predictive factors of malignancy in pediatric thyroid nodules

Background Studies suggest that while most pediatric thyroid nodules are benign, there is a higher rate of malignancy than in adults. We investigate clinical factors that may predict malignancy in pediatric thyroid nodules. Methods A retrospective review of 207 pediatric thyroidectomies was conducted over 15 years at 2 tertiary hospitals. Analyses examined predictive values of 16 clinicopathologic factors associated with cancer. Positive predictive values (PPVs) of fine-needle aspiration biopsy specimens (FNABs) were analyzed independently. Results Malignancy occurred in 41% of patients. After excluding missing data, malignancy was more likely with family history of thyroid cancer (34.2% vs 17.7%; P = .111), palpable lymphadenopathy (34.2% vs 2.9%; P = .001), and hypoechoic nodules (52.2% vs 19.2%; P = .016). Palpable lymphadenopathy indicated greater than 2-fold increased risk for malignancy (relative risk, 2.18; 95% confidence interval, 1.56–3.05). PPVs of FNAB results were 0.94 for malignancy, 0.63 for suspicious for malignancy, and 0.55 for indeterminate lesions. PPV for benign FNAB to be benign on final pathology was 0.71. Conclusion While malignancy is associated with family history of thyroid cancer and hypoechoic lesions, palpable lymphadenopathy had the greatest risk. When compared to adults, a benign FNAB in children is not as accurate and the likelihood that an indeterminate nodule is cancer is greater.