Thyroid nodules and cancer in children and adolescents affected by autoimmune thyroiditis.

OBJECTIVE To investigate the association between juvenile autoimmune thyroiditis (JAT) and thyroid cancer in pediatric patients. DESIGN We conducted a retrospective study among children and adolescents affected by JAT. SETTINGS Data from 6 Italian pediatric endocrinology centers were collected. PARTICIPANTS Three hundred sixty-five children and adolescents affected by JAT diagnosed at 3.6 to 17.0 years of age. INTERVENTIONS All patients underwent clinical examination and thyroid function test every 6 to 12 months and thyroid echography every 12 to 24 months. Fine-needle aspiration biopsy was performed in 39 patients with nodule diameter of 1 cm or larger, as well as in 4 patients with nodule diameter of less than 1 cm and echographic findings suspicious for neoplasm. Twenty-three patients underwent surgery. MAIN OUTCOME MEASURES Thyroid function, echographic pattern, nodule diameter, the presence of lymphadenopathy, and cytologic and histologic diagnoses were considered. RESULTS Thyroid nodules were found in 115 patients; findings in 11 of these were consistent with papillary carcinoma, with 5 exhibiting lymph node metastasis. The prevalence of male sex among patients with cancer was greater than that among patients with JAT (odds ratio [OR], 2.95; 95% confidence interval [CI], 1.44-6.20). The growth of nodules during levothyroxine sodium therapy (OR, 15.60; 95% CI, 1.87-181.90) and the finding of lymphadenopathy (OR, 5.44; 95% CI, 1.05-30.50) were statistically significantly associated with the presence of cancer, while uninodularity and hypoechogenicity were not. CONCLUSIONS The observed prevalences of thyroid nodules and thyroid cancer in our JAT case series were 31.5% and 3.0%, respectively. Papillary carcinoma was the only histotype detected. The finding of lymphadenopathy, a lack of response to levothyroxine therapy, and nodule hypoechogenicity suggested malignancy. Fine-needle aspiration biopsy was reliable in selecting patients for referral to surgery.