Thyroid nodules, sometimes known as goiters, are a common and usually harmless phenomenon that involves a growth of cells within the thyroid gland. However, in some cases, a thyroid nodule may be something more serious, such as cancer or cells that elevate thyroid hormone levels, and thus pose a health risk. In these cases, a thyroid nodule may require the attention of a surgical specialist, usually an otolaryngologist (ENT doctor) experienced in treating disorders of the thyroid and parathyroid glands.
Discovering The Thyroid Nodule
This process often begins with the discovery of a nodule during a physical exam or as an incidental (unexpected) finding on imaging of the head and neck such as a neck CT scan or MRI. Thyroid nodules are rarely large enough to cause pain, discomfort, or visible swelling in the neck. Once a nodule is found, thyroid function blood tests and imaging are usually recommended to better understand any potential risks to your health. The results of the thyroid function blood tests will help the physician decide which type of imaging study is needed. A nuclear scan of the thyroid is usually recommended for patients with elevated thyroid function levels (hyperthyroidism). An ultrasound examination is usually recommended for patients with normal or low thyroid function levels (hypothyroidism).
With a nuclear scan, the patient is given a pill containing a special radioactive dye that is taken up by the thyroid gland. The levels of radiation are very low and therefore safe for the patient. A scan is then performed to study the gland to look for unusual patterns of the dye. If the dye is taken up extensively by the nodule, it is almost always benign. Decreased uptake of dye into the nodule may be a sign of thyroid cancer. In cases like this, an ultrasound and eventual biopsy are usually performed. Because most nodules are found in patients with normal or low thyroid hormone, and because the technology has improved so much with ultrasound imaging, nuclear scans are not performed as often as they once were.
Thyroid Nodule Ultrasound
Thyroid nodules are notoriously difficult to feel and accurately assess on a physical examination alone. In many cases, an enlarged thyroid is caused not just by a single nodule, but rather by several smaller nodules spread throughout the thyroid gland. An ultrasound exam can reveal the size, number, location, and appearance of thyroid nodules in detail, using ultra-high-frequency sound waves that are harmless to the human body. The exam is completely painless and typically only takes about 30 minutes. Sedation is not required because there is no discomfort. After the exam, a radiologist and your surgeon will review the images.
The ultrasound can examine and identify certain features of the nodule that indicate whether a nodule is likely to be harmless, or possibly be a concern for cancer. These features include the shape or texture of a nodule, the presence of calcium deposits, levels of blood flow within the nodule, the presence of a fluid cyst within the nodule, or growth and spread of the nodule beyond the edge of the thyroid gland. The ultrasound exam can also evaluate the lymph nodes surrounding the gland to see if they are normal in appearance. A biopsy will usually be recommended for nodules that are growing quickly, nodules larger than 2 cm in size, or nodules that are smaller, but appear abnormal on the ultrasound.
In some cases, multiple nodules may be seen on ultrasound. These are collectively referred to as a “multinodular goiter.” If one of these nodules is significantly larger than the others, it is known as a “dominant nodule” and is considered to be at higher risk for malignancy. Dominant nodules are often biopsied for this reason.
Fine-Needle Aspiration Biopsy
If an abnormal nodule is evident after imaging, a fine-needle aspiration (FNA) biopsy is usually ordered due to the possibility of thyroid cancer. This procedure involves the passage of a small hollow needle into the nodule. The needle is attached to a syringe, which is used to draw small clumps of cells into the needle from the nodule. Because only a small portion of a nodule may contain cancer, this process is often repeated three or more times to ensure that tissue is sampled from all areas of the nodule. The FNA biopsy is typically performed in an outpatient office setting by a surgeon, radiologist, or endocrinologist with specific training and experience. The physician will typically use ultrasound imaging to guide the biopsy needle and ensure that all areas of the nodule are sampled. The test can be a bit uncomfortable, but anesthesia/sedation is not required and there is minimal pain. The process typically takes 30-60 minutes and results are usually available within a week.
Thyroid Nodule Biopsy Results
Thyroid FNA biopsy results usually fall into one of the following six major categories (in order of level of concern) based on the appearance and quality of the cells obtained:
- Atypical cells or follicular lesion of undetermined significance
- Follicular neoplasm/suspicious for follicular neoplasm
- Suspicious for malignancy
The biopsy results will help inform your surgeon of your risk for thyroid cancer. For the lower-risk categories, a simple follow-up thyroid scan may be all that is necessary. In other cases, a repeat biopsy may be recommended. For higher-risk categories, your surgeon will usually recommend thyroid surgery.
Thyroidectomy is surgery of the thyroid gland in which some or all of the gland is removed. This surgery should only be performed by a surgeon with specialized training in endocrine surgery of the neck, typically an otolaryngologist. Thyroid surgery is performed through a limited incision low in the central neck, which typically heals quickly with little scarring. In some cases, a small surgical drain may be left in place in the neck wound for one to three days following surgery. This drain is later removed painlessly by the surgeon without the need for anesthesia.
For patients with a relatively low risk of cancer, removal of one side, or lobe, of the thyroid gland is generally adequate to safely treat a thyroid nodule. This procedure is called a hemithyroidectomy or thyroid lobectomy. If the risk of malignancy is high or a nodule is known to be cancerous, a total thyroidectomy is often performed to remove the entire gland.
Thyroid surgery is a delicate procedure because several important structures are present near the thyroid gland that must be protected during the gland’s removal. One such structure is a tiny nerve that controls the movement of the vocal cord, called the recurrent laryngeal nerve. This nerve runs from the brain down to the chest before looping back up into the neck and the larynx (voice box). During its return course up through the neck, this delicate nerve runs directly against the back surface of the thyroid gland. If the nerve is disturbed during the removal of the gland, the result can be temporary (or in some cases even permanent) vocal cord paralysis.
There are two separate nerves, one for each vocal cord, traveling along each side of the neck. Damage to one nerve can cause hoarseness or a weak voice, as well as coughing during swallowing, but this is usually temporary and improves as the nerve heals or the vocal cords adapt to the weakness. However, if both nerves are damaged during surgery, the result can be paralysis of the vocal cords and obstruction of breathing that can be life-threatening without placement of a surgical bypass of the airway, known as a tracheostomy. For this reason, the laryngeal nerve is always monitored with special electrodes during surgery to confirm its location and proper function. If a nerve is not functioning normally after the removal of one side of the thyroid gland, the surgery is aborted until a later date to allow the nerve to recover. This is also why total thyroidectomy is performed only when necessary to remove thyroid cancer.
Parathyroid glands, a group of four tiny glands that rest on the back surface of the thyroid gland (two on each side), are also important structures during thyroid surgery. These glands are critical for controlling the body’s calcium levels, an important electrolyte for nerve and muscle function. During thyroid surgery, the parathyroid glands are identified and preserved whenever possible. Fortunately, only half of one gland is needed to meet the body’s demands for parathyroid hormone production, so the loss or damage of one or even several glands will usually not cause any harm to the patient. During total thyroidectomy, all four parathyroid glands are placed at risk of damage or removal, which increases the risk of prolonged or even permanent hypocalcemia (low blood calcium levels) after surgery. If this occurs, patients may require ongoing calcium and vitamin D replacement as well as close, careful monitoring of their blood calcium levels. This risk further explains why total thyroidectomy is performed only when necessary to remove thyroid cancer.
Despite all these risks, thyroid surgery is generally very safe and successful when performed by a qualified and experienced ENT surgeon. Many patients return home the same day after thyroid surgery without an overnight hospital stay.
After Thyroid Surgery
Patients typically report very little postoperative pain or downtime following thyroidectomy, and healing is usually complete within two weeks. Afterward, your surgeon may want to monitor your calcium levels with blood tests or observe your vocal cord function with an endoscopic exam of the vocal cords, called a laryngoscopy. If a total thyroidectomy is necessary, thyroid hormone replacement pills will be required indefinitely following surgery. Usually, a follow-up visit one to two weeks after surgery is scheduled to inspect the incision and remove any sutures. After that point, thyroid hormone levels are monitored periodically by an endocrinologist or primary care physician to assess the need for thyroid hormone replacement. However, most patients undergoing a thyroid lobectomy will not require any thyroid hormone replacement because the remaining thyroid lobe is usually able to meet the body’s requirements for thyroid hormone production.
The ear, nose, and throat specialists at CornerStone Ear, Nose & Throat have years of experience performing thyroid surgery and helping patients with thyroid nodules. To learn more or to make an appointment, call 704-752-7575.