Thyroid Nodule Patient Information

Anh Q. Truong, MD

Bellevue ENT

1231 116th Avenue NE, Suite 915

Bellevue, WA 98004

Phone: (425) 454 - 3938

What is the thyroid gland?

The thyroid gland is a butterfly-shaped endocrine organ located in the front of your neck, under the skin and muscle and over the trachea (windpipe). The thyroid gland has two lobes, one on each side of the trachea, and it is usually not visible or palpable externally.

Typically, there are two parathyroid glands located behind each thyroid lobe. Although there is a close anatomical relationship, the parathyroid glands are separate organs from the thyroid gland and serve a different function – primarily regulating calcium level in the blood. In addition, coursing immediately behind each thyroid lobe is a nerve called the recurrent laryngeal nerve. The nerves originate in the chest and innervate the vocal cords, essential in controlling voice and breathing function. Other nearby structures include the superior laryngeal nerves, which control throat sensation and the pitch of your voice, and the carotid arteries.

Figure 1. Anatomy of the thyroid gland and surrounding structures. Source: JAMA.com and Rochester.edu

What are the functions of the thyroid gland?

The thyroid gland secretes thyroid hormone, which regulates physiological function in your body including metabolism. Thyroid hormone has a major role in regulating body temperature, weight, heart rate, mood, energy level, libido, sleep, growth, GI function and brain maturation (in children).

Disorders of thyroid function can lead to hypothyroidism (e.g. Hashimoto thyroiditis) or hyperthyroidism (e.g. Grave’s thyroiditis), altering normal physiologic function. Secretion of thyroid hormone is generally controlled by the pituitary gland in the brain that secretes thyroid stimulating hormone (TSH). The thyroid gland also secretes calcitonin, which plays a minor role in bone and calcium metabolism.

What is a thyroid nodule?

A thyroid nodule is an abnormal growth of thyroid cell that grows and forms a lump within the thyroid gland. The description is non-specific and it is synonymous with a thyroid tumor, a thyroid mass or a thyroid cyst. Thyroid nodules may present as a single lesion or as multiple lesions. The vast majority of thyroid nodules are benign and do not alter normal metabolism and physiology. However, a small subset can be cancerous (5-10%) or function autonomously to secrete thyroid hormone without appropriate regulation.

What is a thyroid goiter?

A thyroid goiter is an abnormal enlargement of the thyroid gland. Patients with a thyroid goiter may have normal thyroid function (euthyroid), elevated thyroid hormone (hyperthyroidism), or thyroid hormone deficiency (hypothyroidism). Common causes of a thyroid goiter may include iodine deficiency, multinodular thyroid goiter, Hashimoto’s thyroiditis and Grave’s disease. Due to the potential for a cancer, the initial workup for a thyroid goiter is similar to that of a thyroid nodule.

How does a thyroid nodule typically present?

Most thyroid nodules are discovered incidentally through routine examination or from head and neck imaging for other reasons. They are extremely common and about half of the patients over the age of 60 will have a thyroid nodule, 90% of which are benign. Some patients may notice a lump in the neck when looking in the mirror or feeling the neck. In most cases, patients are completely asymptomatic when the nodule is found. In rare cases, the nodule can be large enough to cause compressive symptoms including trouble swallowing, trouble breathing, voice change, and pain. Some nodules may secrete thyroid hormone, leading to symptoms of hyperthyroidism including elevated heart rate, heat intolerance, diarrhea, weight loss, hair loss, restlessness, and trembling.

What should I expect during my visit with an ENT doctor for a thyroid nodule?

During your visit, your ENT doctor will perform a complete history and physical exam. If there is any concurrent voice or throat problem, your doctor may evaluate your larynx and vocal cord with a mirror or a fiberoptic endoscopic. Depending on your history and examination, your physician may refer you to obtain additional studies including a blood test, imaging, and a biopsy.

What are additional tests needed for work-up of a thyroid nodule?

Initial work-up for a thyroid nodule includes a thyroid function test and an ultrasound (if imaging is not already available). Additional test depends on a variety of factors including family history of thyroid cancer, history of radiation exposure, the size of the thyroid nodule, the quality of the thyroid nodule on imaging, and abnormalities in metabolic function. Depending on the result of the initial work-up, additional tests including a CT scan, a radioactive iodine uptake test, and/or a fine needle biopsy (FNA) may be indicated. Special genetic markers can be performed if the FNA is equivocal to further guide management. Current research is looking into many other genetic tests to more accurately predict the pathology and reduce unnecessary surgery.

Figure 5. Ultrasound & fine needle aspiration of a thyroid nodule. Source: MedlinePlus and drug.com

What are the different types of thyroid nodules?

The pathology of most thyroid nodules can usually be determined by the routine work-up discussed above. The result may show a non-functional (not secreting hormone) vs a functional (secreting hormone) nodule. The pathology from the needle biopsy may show a benign nodule vs thyroid cancer (malignant). A subset of fine needle biopsies may have inconclusive (non-diagnostic) or intermediate (indeterminate) features suggestive of possible cancer. In these cases, additional genetic testing may help establish a specific diagnosis or guide the next step in management.

One particular result from a fine needle biopsy may show a “follicular neoplasm.” This result is often non-specific given that cells from both a benign follicular adenoma and a malignant follicular thyroid cancer are often indistinguishable from a needle biopsy. As a result, additional management is guided by the patient’s other risk factors and presentation.

What additional treatment is needed?

The management of thyroid nodules is complex and is different for each individual patient. Your management team may include your ENT doctor, endocrinologist, and/or your primary care provider. Depending on the result of your work-up, your history, social factors and risk factors, the treatment plan may include routine physical examination, close follow-up, repeat ultrasound, repeat fine needle biopsy (FNA) and/or surgery.

References:

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