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Thyroid Disease

Thyroid Nodules
Thyroidectomy

What are Thyroid Nodules?

Thyroid nodules are commonly diagnosed. They are frequently found unexpectedly on routine physical examinations or imaging studies. They can present symptomatically as a visible lump in the neck, a pressure impairing swallowing, or, in rare cases, as a mass compressing the trachea and causing airway obstruction. Once discovered, evaluation typically centers on determining whether surgical excision will be required.

Symptoms and Types:

Nodules can be divided generally into benign (non-cancerous) and malignant (cancerous) types. Approximately 90% of nodules discovered turn out to be non-cancerous. Among benign nodules, colloid cysts, follicular adenomas, and nodules due to diffuse inflammatory conditions predominate. Malignant thyroid nodules are generally one of four types: papillary, follicular, medullary or anaplastic. Of these, the papillary and follicular types are by far the most common. Other, unusual types of nodules, include toxic hyperfunctioning nodules, and lymphomas.

Diagnosis and Tests:

Once discovered, a number of studies may be recommended in order to evaluate thyroid nodules, depending on the individual situation of the patient. A thyroid ultrasound is a common tool used to determine the exact size of the nodule, as well as other qualities, such as whether it is cystic or solid. A nuclear medicine thyroid scan may be used to determine whether the nodule is active in secreting thyroid hormone, which may provide clues about its potential for malignancy. Blood tests may be performed to determine the hormonal state of the gland, although these generally do not provide information regarding whether the nodule is malignant. Other imaging studies, such as CT scan or MRI scan may be recommended in special situations.

Fine Needle Biopsy: Frequently, a biopsy of the nodule using a fine needle through the skin is recommended to try to determine whether the tumor is malignant. If the nodule is easily felt, this can be done under local anesthetic in the office. If the nodule is more difficult to feel, biopsy of the nodule under ultrasound guidance by the radiologist may be required.

Biopsy Results: Needle biopsy results may reveal findings clearly indicating that the tumor is either benign or malignant, or the results may be inconclusive, and require interpretation along with other clinical findings to determine the risk for malignancy. Findings of colloid and cystic fluid are frequent findings suggesting benign conditions. Findings suggestive of papillary thyroid carcinoma are strong evidence of malignancy. However, findings of follicular cells can be difficult to interpret, since these are found both in benign tumors called follicular adenomas, and in malignant tumors called follicular carcinomas. Unfortunately, this can be a common predicament. Fine needle biopsies help physicians with their recommendations regarding the relative need for surgery, but they cannot absolutely determine whether a particular nodule is benign or malignant. Only surgical removal of the gland can demonstrate this definitively.

Treatment and Care:

Once the evaluation is complete, the physician assimilates these results, along with other factors, including the age of the patient, other significant health issues, and patient preferences to determine whether surgery (thyroidectomy) is recommended, or whether the nodule should be followed without surgery. If surgery is not recommended, follow-up ultrasounds or sometimes follow-up biopsies may be needed to ensure that the nodule does not show malignant features in the future.

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What is a Thyroidectomy?

Thyroidectomy, surgical removal of the thyroid gland, is performed for a variety of thyroid abnormalities. Among the more common reasons are thyroid nodules, thyroid cysts, thyroid enlargement due to multi-nodular goiter, and some cases of Graves Disease.

Surgery is performed as either a lobectomy (removal of one lobe, or half, of the gland) or total thyroidectomy (removal of the entire gland). The type of surgery that is performed depends on the reason for surgery. Patients with benign disease involving only one lobe generally require only a lobectomy, whereas patients with malignant disease, or benign disease involving both lobes may require total thyroidectomy.

Thyroidectomy is performed under a general anesthetic in an operating room. A horizontal incision is made in the neck, between the voice box and the sternum. Once the gland is identified, it is dissected away from surrounding tissues. Two important structures are identified during this dissection. The first structure is the recurrent laryngeal nerve. This nerve, one on each side of the neck, travels upward from the chest, under the gland and into the voice box, where it is responsible for moving the vocal cord on that side. The second structure is the parathyroid gland. There are four of these glands, two on each side of the neck, attached to the back of the thyroid. Each is about the size of a lentil bean. They are responsible for maintenance of the body’s calcium levels. Both the nerves and the parathyroid glands are carefully dissected away from the thyroid gland to preserve them.

Once the gland is removed, the specimen is sent to the pathologist for examination to determine what type of disease is present. Sometimes, a frozen section analysis is performed during the surgery if this will influence the outcome of the surgery. In this situation, the specimen is removed and sent immediately to the pathologist while the patient is still under anesthesia. The pathologist performs a quick analysis of the specimen and reports the findings back to the operating room so that the surgeon can use this information to make decisions about the remainder of the surgery. Permanent section analysis takes place after the surgery, when the specimen is carefully studied, and a final, official diagnosis is made.

The specific risks of thyroid surgery arise from possible injury to the recurrent laryngeal nerves and parathyroid glands. Injury to the nerve results in vocal cord weakness or paralysis, with a resultant hoarse, breathy voice. If the nerve is bruised or stretched, the hoarseness will generally recover; however, if the nerve has been severed, the hoarseness will be permanent. Inadvertent removal of all four parathyroid glands results in permanent hypoparathyroidism, a permanent difficulty regulating the body’s calcium levels. Both of these complications are rare. Temporary fluctuations in the body’s calcium levels after total thyroidectomy are common, and are generally managed with temporary calcium supplementation. After thyroid lobectomy, thyroid supplementation is generally not needed, since the remaining lobe will produce sufficient thyroid hormone. However, after total thyroidectomy, lifelong daily thyroid supplementation is necessary.

Recovery from thyroid surgery is generally easy, although this varies from person to person. Postoperative pain is usually moderate and lasts a few days. Most patients resume a full diet shortly after surgery. Activity is limited for one to two weeks to avoid straining the neck, after which full activities can be resumed. The incision usually heals uneventfully, although some individuals may have a tendency to develop thick, hypertrophic scars or keloids. Protecting the incision from the sun for the first year after surgery is the most important precaution that a patient can take to preserve an acceptable scar.

By Cary Moorhead, MD