A thyroid nodule is an area of abnormal growth of the thyroid gland. They are very common. In fact almost half of adults have at least one. Many people have more than one nodule. Most nodules are found incidentally on imaging studies (for example an MRI of the neck or a CT of the chest). 4-5% of all nodules turn out to be thyroid cancer. To rule out thyroid cancer we may do a fine-needle biopsy of thyroid gland. Otherwise a thyroid nodule may be making thyroid hormone out of control and cause an elevated thyroid level (hyperthyroidism). To rule this out we do a simple thyroid blood test. Thyroid nodules otherwise do not affect the function of the thyroid gland. There is no specific reason why people get thyroid nodules. It’s just a bi-product of the process of making thyroid hormone.
The most important thing about thyroid nodules is not to worry about them. Thyroid cancer is not typically like other cancers. It does not typically spread and cause problems with peoples’ health. Rarely it can cause problems so we do treat thyroid cancer when we diagnose it. The treatment is simply to remove the thyroid gland often followed by something call radioiodine ablation. There’s no chemotherapy, radiation, or anything nasty like that.
If we do biopsy the nodule, and it is not cancer, we may follow it with ultrasound from time to time. There is no treatment to shrink nodules. If you do not have thyroid cancer, an abnormal thyroid blood test, or any significant symptoms from the nodule there is no reason to treat it.
Many people are told that they have a thyroid nodule, but they really just have a colloid cyst. Colloid is a material that the thyroid gland uses to store its hormone. Often times the colloid will collect in a cyst. Colloid cysts are extremely common and they are of no clinical significance.