Thyroid Nodules - Causes
What causes thyroid nodules?
Although the molecular mechanisms that cause nodules are not fully understood, thyroid nodules are known to be due to either benign or malignant conditions. There are only a few known risk factors that predispose a person to develop thyroid nodules. Your endocrinologist at Houston Thyroid and Endocrine will review these risk factors with you during your thyroid nodule clinic appointment. It is important to note that the likelihood of ruling out thyroid cancer by risk factors and patient history alone is only 60%.
If you have a thyroid nodule that needs evaluation please contact our thyroid nodule coordinator. Visit our Thyroid Nodule Clinic
Risk factors for cancer in a thyroid nodule
As a patient ages, the rates of thyroid nodularity increase.
A nodule in a young person (<20 years old) is twice more likely to be a cancer than in an adult.
The rate of thyroid cancer is higher in men than women.
Previous radiation treatment to the head and neck region as a child or adolescent. Radiation used to be used to treat acne or tonsil enlargement in the 1950's and 1960's.
Hematopoietic stem cell transplant increases the rates of thyroid cancer.
Smoking, especially areas that have iodine deficiency
A family history of thyroid cancer or family history of mulitple endocrine neoplasia (MEN) type 2
Factors that suggest a benign cause of a thyroid nodule
A family history of Hashimoto's thyroiditis, benign nodule, or goiter
History of hyperthyroidism, especially if a "hot nodule"
A sudden increase in size of the nodule with pain or tenderness, suggesting a cyst or localized thyroiditis.
The benign conditions associated with thyroid nodules
Multinodular goiters that have "colloid adenomas"
Hashimoto's Thyroiditis, also known as chronic lymphocytic thyroiditis
Thyroid Cysts: colloid, simple, or hemorrhagic
Microfollicular or cellular adenomas
Hurthle cell adenomas
Macro- or Microfollicular pattern
The malignant conditions associated with thyroid nodules
Hurthle cell type
Primary thyroid lymphoma
Metastatic carcinoma (breast, renal cell, etc)
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