Thyroid Nodules | Symptoms & Causes

What causes thyroid nodules?

The causes of thyroid nodules in children are mostly unknown. Some factors that may increase the risk of developing thyroid nodules include exposure to radiation (such as from medical treatments) and certain genetic conditions that cause thyroid nodules or thyroid cancer. What causes some children to develop thyroid nodules and thyroid cancer is an area of active research in our Thyroid Center.

  • Exposure of the thyroid to radiation, including radiation used to treat other cancers, increases the risk of developing thyroid nodules and thyroid cancer. Some other childhood cancers that are sometimes treated with radiation that may affect the thyroid include leukemias, lymphomas, brain tumors, and neuroblastomas, as well as cancers that require a bone marrow transplant. The younger a child is when exposed to radiation, the more the risk of thyroid nodules and cancer is increased.
  • Thyroid nodules and cancer can occur as part of certain genetic conditions. Some of these conditions may be inherited (familial), and some can occur just in the child without being present in the parents. Some genetic syndromes that increase the risk of thyroid nodules and cancer include:
    • PTEN hamartoma tumor syndrome may include features like a large head; vascular malformations; neurodevelopmental disorders; and tumors of many organs including the skin, breast, uterus, and thyroid. Thyroid nodules and thyroid cancer can occur in patients with PTEN mutations as young as 6 years old. (PTEN syndromes also include several other syndromes like Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, and Proteus syndrome).
    • DICER1 syndrome increases the risk of several types of tumors, including tumors of the lungs (often in infancy), ovaries, kidneys, and thyroid.
    • Familial adenomatous polyposis (FAP) causes the growth of numerous polyps (abnormal growths or tumors) in the gastrointestinal tract. It also causes an increased risk of other tumors, including thyroid cancer.
    • Multiple endocrine neoplasia type 2 (MEN2) is a familial condition that causes medullary thyroid cancer, sometimes in childhood or even infancy, as well as tumors of the adrenal glands (pheochromocytomas) and sometimes the parathyroid glands.
    • Familial medullary thyroid carcinoma (FMTC) is a familial form of medullary thyroid cancer that is similar to MEN2 except that it does not cause any other types of tumors.

Sometime a lump in the neck that seems like a thyroid nodule is actually a thyroglossal duct cyst, which is a fluid-filled sac caused by an abnormality in how the thyroid forms during a baby’s development in the womb. Other types of neck masses and cysts sometimes can also be mistaken for thyroid nodules. Careful evaluation by an experienced team is necessary for suspected thyroid nodules, because thyroglossal duct cysts and other neck masses are evaluated and managed differently than true thyroid nodules.

What are the symptoms of thyroid nodules?

Most children with thyroid nodules feel fine and have no symptoms.

While symptoms may vary from child to child, the most common include:

  •  a visible lump in the neck
  • a sensation of a lump in the throat when swallowing (or more rarely, difficulty with swallowing)
  • unexplained hoarseness

A rare type of thyroid nodule called an autonomous nodule (also known as a “toxic nodule” or “hot nodule”) can produce too much thyroid hormone. This can cause symptoms like:

  • weight loss
  • feeling too hot or sweaty
  • heart palpitations (heart racing, pounding, or “skipping beats”)
  • tremor of the hands
  • frequent bowel movements
  • difficulty concentrating

Autonomous nodules are usually benign, but special evaluation is needed to determine if a thyroid nodule is of this type.

Keep in mind that similar symptoms can be associated with more common medical problems and conditions. Therefore, it is important to consult your child's physician for a diagnosis if your child has one of these symptoms.