Thyroid follicular carcinoma in a fourteen-year-old girl with Graves' disease

Here we present the case of a 14-yr-old girl who developed thyroid follicular carcinoma accompanied by Graves' disease. She was diagnosed with Graves' disease at 10 yr of age and soon achieved a euthyroid state after starting treatment. When she was 13 yr of age, her hyperthyroidism and goiter worsened despite medical therapy. Multiple nodules were found in her enlarged thyroid gland by ultrasonography. Her serum Tg level seemed within the normal range. She underwent near-total thyroidectomy for control of thyroid function. Histopathological study demonstrated that multiple oxyphilic follicular neoplasms were surrounded by the thyroid tissue compatible with Graves' disease. Capsular invasion was identified in one of the nodules, and thus the histological diagnosis was minimally invasive follicular carcinoma. She did not have signs suggesting metastasis, and has had no relapse for 18 mo after the operation. Although some previous studies showed a high prevalence of thyroid cancer with an aggressive nature in adult patients with Graves' disease, few reports about thyroid cancer accompanied by Graves' disease are available in children. The present case, however, suggests that careful investigation is needed when we detect thyroid nodules or progressive thyroid enlargement, especially in children with Graves' disease.