Differentiated thyroid carcinomas in children and adolescents. An analysis of differentiated thyroid carcinomas in children and adolescents revealed that the incidence was 3.05% of total number of patients with differentiated thyroid cancers in all age groups. There was a female preponderance. The incidence of papillary, follicular and papillary with follicular elements was equal. There were no papillary carcinomas observed in children younger than 10 years. The predominant mode of presentation was a solitary nodule of thyroid and some of them had associated cervical adenopathy. A considerable number presented with only cervical adenopathy. The incidence of nodal metastases was 50% at time of presentation and lung involvement was present in 15% of children at the time of diagnosis. Radioiodine treatment was given in 70% of children. Ablation was achieved in 86% of patients given two doses of radioiodine (200 millicuries). The more resistant cases were those with lung and nodal metastases. There was complete ablation in 100% with only residual thyroid tissue, 83% in those with associated nodal metastases, and 57% in those with lung involvement. Average duration of follow-up was 10.3 years (range, 2 to 19 years). Recurrence rate or relapse was observed in 8.5% and was in the regional nodes. There was no recorded mortality due to the disease. 