Types of Thyroid Nodules

Nodules are small tumors within a thyroid gland. They are not necessarily cancerous. Most are benign. The following is a brief description of the several different types of thyroid nodules.

Thyroid Adenoma

Thyroid adenomas come in different forms and have different names, but they are benign growths of normal thyroid tissue. These do not require treatment if they are not causing compressive symptoms. If they are not causing symptoms, most of these are watched with neck ultrasound.

Toxic Adenoma

Toxic adenomas are thyroid adenomas that secrete excess thyroid hormone.  It causes an overactive thyroid, also known as, hyperthyroidism.  Malignancy from a toxic adenoma is very rare (between 1% to 8%).

Thyroid Cysts

Thyroid cysts are fluid-filled nodules within the thyroid.  Pure thyroid cysts are usually benign (non-cancerous).


Any enlargement of the thyroid gland is referred to as a “goiter.” Goiter can be caused by Hashimoto’s Thyroiditis (an autoimmune disease) and iodine deficiency. These do not require treatment unless the goiter is causing compressive or hyperthyroid symptoms.

Multinodular Goiter

A multinodular goiter is an enlarged thyroid gland containing multiple nodules. Most often, these nodules are benign. As above, these only require treatment if you are experiencing compressive or hyperthyroid symptoms, or if one or more of the nodules is suspicious for thyroid cancer.

Thyroid Cancer

Thyroid cancer forms when normal thyroid cells undergo genetic changes that cause them to grow in an abnormal way. The most common types of thyroid cancer, papillary and follicular, which are typically less aggressive than other thyroid cancers (hurthle, medullary, poorly differentiated/anaplastic thyroid cancer).

There are multiple types of thyroid cancer:

  • Papillary thyroid cancer
  • Follicular thyroid cancer
  • Hurthle thyroid cancer
  • Medullary thyroid cancer
  • Poorly differentiated and anaplastic thyroid cancer

Learn more about types of thyroid cancers