Thyroid Carcinoma Presenting in Childhood or after Treatment of Childhood Malignancies: An Institutional Experience and Review of the Literature

Background/Purpose: Thyroid carcinomas can occur as a primary malignancy (PTM) or secondary after another malignancy (STM). Information about the presentations and outcomes of patients with STM are limited. The authors sought to compare the clinical characteristics, course, and outcomes of patients with primary or secondary thyroid malignancies. Methods: The authors reviewed the medical records of 8 children with PTM and 17 children with STM referred to St Jude Children's Research Hospital between February 1962 and February 2002 for evaluation and treatment of malignant thyroid carcinoma. Results: The 8 children who had primary thyroid carcinoma had it diagnosed at a median age of 12.5 years (range, 7.3 to 16.3 years). Seven patients had papillary carcinoma, and 1 patient had follicular carcinoma. Three of the 8 (37.5%) had metastatic disease involving regional lymph nodes; 2 patients (25.0%) had lung metastases. Six patients required radioactive iodine (I 131) ablation for residual or metastatic disease after surgical resection. All 8 patients remain alive a median of 22.6 years after diagnosis (range, 0.7 to 30.5 years); 1 continues to receive radioactive iodine (I 131) ablation for persistent disease. Seventeen patients had thyroid carcinoma as a second malignant neoplasm after treatment for acute lymphoblastic leukemia (n = 6), Hodgkin's disease (n = 5), central nervous system tumor (n = 2), Wilms' tumor (n = 1), retinoblastoma (n = 1), non-Hodgkin's lymphoma (n = 1), or neuroblastoma (n = 1). Patients with secondary thyroid carcinoma presented at a median age of 21.5 years (range, 15. 3 to 42.6 years), a median of 16.2 years (range, 0.9 to 29.2 years) after diagnosis of the primary cancer. Twelve of the 17 patients (70.6%) had received radiation to the thyroid gland during therapy for the primary cancer. Four patients (23.5%) had metastatic disease involving regional lymph nodes. Six patients (35.3%) required I¹³¹ ablation for residual or metastatic disease after thyroidectomy. At the time of this report, all 17 patients are alive and in continue to be free of disease. Conclusions: Pediatric thyroid carcinoma is uncommon and responds well to current therapy. Given the limited period of follow-up of our cohort of secondary malignant thyroid tumors that arise after childhood cancer, these lesions appear to have similar presentations and outcomes when compared with primary carcinomas and can therefore be managed in the same manner.