Key Points
Î According to the Surveillance, Epidemiology and End Results (SEER)
program, new cases of thyroid cancer in people < age 20 represent
1.8% of all thyroid malignancies diagnosed in the United States. The
incidence appears to be increasing.
Î Compared with adults, thyroid neoplasms in the pediatric population
exhibit differences in pathophysiology, clinical presentation, and long-
term outcomes.
Î The most common presentation for DTC in children is that of a thyroid
nodule. However, papillary thyroid cancer (PTC) also frequently
presents as cervical adenopathy with or without a palpable thyroid
lesion, or as an incidental finding after imaging or surgery for an
unrelated condition. Occasionally, the diagnosis is made only after the
discovery of distant metastases.
• PTC accounts for 90% or more of all childhood cases. Follicular thyroid
cancer (FTC) is uncommon while medullary thyroid cancer (MTC), poorly
differentiated tumors and frankly undifferentiated (anaplastic) thyroid carcinomas
are rare in young patients.
Î Furthermore, therapy that may be recommended for an adult may not
be appropriate for a child who is at low risk for death but at higher risk
for long-term harm from over-aggressive treatment.
Î The pediatric age should be limited to a patient ≤18 years of age.
Establishing a uniform upper limit of age will afford an opportunity
to better define the potential impact of growth on tumor behavior.
From a pragmatic point of view, individual centers may transition
pediatric patients to adult care anywhere between 18 and 21 years of
age. Clinicians may manage the "child" under these guidelines until
transition has been completed. (C)
