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.