Differentiated thyroid carcinoma: comparison of histopathologic characteristics, clinical course, and outcome between young children and adolescents.

Differentiated thyroid carcinoma is rare in patients younger than 21 years, especially in children, but it is associated with a greater risk of metastases and recurrence. The aim of our study was to compare the characteristics, clinical course, and outcome of the disease between young children (≤16 years) and adolescents (17-21 years). We reviewed the medical records of 62 young children and adolescents (47 females, 15 males, ≤21 years) with DTC who were diagnosed between 1990 and 2010 and admitted for radioiodine therapy, and compared the histopathologic features, amount and session(s) of radioiodine administration, and outcome in both groups. Young children presented with larger tumor size, more aggressive pathological features, higher incidence of locoregional and distant metastasis, and needed more admissions, and higher amounts of radioiodine for treatment. While there were more disease-free patients at the end of follow-up in the adolescents, the number of patients with stable or progressive disease was higher in younger group. Based on the results of our study, we support the more aggressive approach to DTC treatment in young children, including total thyroidectomy along with more extensive cervical lymph node dissection, L-T4 therapy in suppressive doses, and multiple sessions of postsurgical radioiodine therapy as necessitated.