About 50 percent of the world’s population has thyroid nodules, which are fluid-filled or solid lumps found in the thyroid, according to Columbia University Medical Center.
As a person gets older, her risk for developing a thyroid nodule increases. MedlinePlus added that women have thyroid nodules more often than men.
Several conditions increase a person’s risk of developing a thyroid nodule. For example, people who have thyroid disorders, such as Hashimoto’s disease, may develop a thyroid nodule.
With Hashimoto’s disease, patients have an inflammation of the thyroid gland, which reduces its activity. Another possible cause is an iodine deficiency. When the body does not get enough iodine, it may cause the production of thyroid nodules, according to the MayoClinic.com.
However, iodine deficiency is a rare problem in the United States, due to the addition of iodine in table salt. An overgrowth of normal thyroid tissue, called thyroid adenoma, may lead to thyroid nodules.
Degenerating thyroid adenomas may result in fluid-filled nodules.
Some cases of thyroid nodules are cancerous. Columbia University Medical Center noted that 5 percent of thyroid nodule cases are malignant, with the incidence of malignant nodules higher in men than women.
Certain people have a higher risk of malignant thyroid nodules. For example, individuals with a family history of multiple endocrine neoplasia type II and thyroid cancer, especially medullary thyroid cancer, have a higher risk of a malignant thyroid nodule, according to MedlinePlus.
The risk is increased in individuals who are younger than age 20 or older than age 70. Receiving radiation to the neck or head also increases the risk. Other risk factors include a hard thyroid nodule and a nodule stuck to adjacent structures.
While many patients with thyroid nodules do not have symptoms, some patients may if the nodule is large or if it produces excess thyroxine, resulting in hyperthyroidism.
With a large thyroid nodule that is putting pressure on nearby structures, patients may have difficulty swallowing or breathing.
Hoarseness of the voice may occur.