Differentiated Thyroid Cancer in Children and Adolescents: Clinicopathological Characteristics of 32 Patients Followed up in our Pediatric Endocrinology Unit.

[OBJECTIVES] This study aims to investigate the clinical and pathological features of patients with differentiated thyroid cancer (DTC) treated at our tertiary care institution.

[METHODS] Thirty-two children and adolescents followed up with the diagnosis of DTC between 2001 and 2017 were enrolled. We classified patients with DTC into two groups as below and above 10 years of age, and compared their clinical and pathological features.

[RESULTS] The mean age at presentation was 11.2±4 years. The female/male ratio was 7 (28:4). The diagnosis was papillary thyroid cancer (PTC) in 90.6% (n=29). The frequencies of lymph node and pulmonary metastases were 53.1% and 21.8%, respectively. The groups were comparable in terms of gender, initial clinical signs and tumor histopathology. The mean tumor size was greater in the younger age group (p=0.008). However, there was no difference between the two groups in terms of lymph node and pulmonary metastases. The pathological parameters associated with tumor aggressiveness were also similar between the groups, except lymphovascular invasion. Lymphovascular invasion was more frequent in the younger age group (p=0.01). Patients with lymph node and pulmonary metastases were more likely to have extrathyroidal extension and lymphovascular invasion.

[CONCLUSION] PTC was the most common type of DTC and presented with considerable rates of lymph node and pulmonary metastases. Tumor size was greater and lymphovascular invasion was more common in younger patients. Overall prognosis was favorable despite high rates of lymph node and pulmonary metastases.