Endocrine Abstracts

Introduction: The aim of the present study was to evaluate if demographic and histological characteristics as well as the long-term outcome of thyroid cancer was different in children and adolescents with and without autoimmune thyroiditis taking into consideration that information in the literature is scarce.

Methods: The medical records of children and adolescents (≤21-year-old) followed up in Theagenio Cancer Hospital due to histologically proven thyroid carcinoma were reviewed. The following data were recorded: year of diagnosis of thyroid cancer, age at diagnosis, gender, family history of thyroid cancer, history of external radiation therapy, histological type (papillary and variants, follicular, medullary and poorly differentiated), tumour size, multifocality, lymph node metastases, vascular invasion, infiltration of thyroid parenchyma or surrounding soft tissues and presence of distant metastases. Information about the presence of anti-Tg and anti-TPO was also collected. All histological material was reviewed by a second pathologist with special attention in order to identify findings of lymphocytic thyroiditis. Data analysis was performed using the statistical package SPSS.

Results: One hundred and twelve children and adolescents (mean age 18.1±3.0 years) were diagnosed with thyroid cancer from 1980 to 2013. Histology revealed papillary thyroid carcinoma (PTC) in the majority of the cases (88.4%). Thirty two patients (28.6%) presented histological characteristics compatible with lymphocytic thyroiditis. No differences were found in anthropometric characteristics between patients with and without lymphocytic thyroiditis. Infiltration of thyroid parenchyma was more frequent in the Hashimoto thyroiditis group compared to patients without (75.0 vs 47.5% respectively, P=0.015). Familial PTC was more frequent in patients with lymphocytic thyroiditis compared to those without lymphocytic thyroiditis (22.2 vs 2.8% respectively, P=0.006).

Conclusion: Children and adolescents with Hashimoto disease present more frequently familial PTC as well as thyroid cancer with invasive characteristics. Larger epidemiological studies are needed to confirm our results.