The most common pediatric head and neck tumors occur in the thyroid — a butterfly-shaped gland in the neck. The thyroid is responsible for producing hormones that are important for your child’s growth and metabolism — the process by which the body converts food and drink into energy. A thyroid nodule is a lump that forms within the thyroid gland. It can be solid or filled with fluid (cystic); not all thyroid nodules in children require surgery. Childhood thyroid cancer is relatively rare. More than 75% of thyroid nodules that occur in children and adolescents are benign. However, about 20 to 25% of thyroid nodules are malignant and require prompt treatment to achieve the best possible outcome. While childhood thyroid cancer can occur at any age, it tends to appear most often in the teenage years. In fact, thyroid cancer is the second most common cancer among adolescents ages 15 to 19.