Solitary Thyroid Nodule Clinical Presentation

Updated: Mar 06, 2017
  • Author: Andre Hebra, MD; Chief Editor: Robert P Hoffman, MD  more...
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Presentation

History

Most patients with a thyroid nodule have an asymptomatic neck mass, usually discovered by a parent or a pediatrician on routine examination. Upon evaluation, close attention should be paid to the presence of symptoms, the course of development of the mass, family history, and exposure to x-rays.

Risk factors

A history of head and neck irradiation increases the risk of nodularity and malignancy. This correlation is well-documented. Although the use of head and neck irradiation for benign conditions has decreased, this factor remains important, especially in patients with prior malignancies.

A family history of thyroid disease, benign or malignant, can be found in a significant number of patients with thyroid cancer and may help determine which patients have an increased risk. However, family history of thyroid disease also increases risk for autoimmune thyroiditis, and malignancy should not be assumed automatically.

Characteristics of the nodule

The history of the mass should be reviewed carefully. Time of initial appearance, rate of growth, and any associated symptoms especially can assist the clinician in determining the malignancy potential of the mass.

Rapid growth is an indicator of malignancy. Therefore, further diagnostic tests should be expediently obtained.

Transient tenderness within the mass at any time may signify an inflammatory process. However, this same symptom may also be caused by tumor hemorrhage, necrosis, or cyst formation. This information can be used to assist the clinician in determining malignancy of the mass. [9]

Thyroid dysfunction

Although most patients are asymptomatic, some exhibit evidence of altered levels of thyroid hormones or nerve involvement.

Symptoms of hyperthyroidism include nervousness, heat intolerance, diarrhea, muscle weakness, and loss of weight and appetite.

Hypothyroidism may result in cold intolerance, constipation, fatigue, and weight gain, which, in children, is primarily caused by the accumulation of myxedematous fluid.

Signs and symptoms of local nerve involvement should trigger rapid investigation because it may be indicative of local invasiveness from malignancy. The most important of these signs are dysphagia and hoarseness.

Obtaining a thorough history can be helpful for assessing malignancy and determining the need for surgery and/or medical therapy.

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Physical

In patients with a thyroid mass, careful physical examination is a key step in evaluating malignancy. Most patients are asymptomatic, but exophthalmos rarely may be present in a person with a hyperfunctioning nodule. In one study, 55% of pediatric patients with thyroid cancer had no other symptoms than a neck mass, whereas 23% had only neck and cervical masses. Therefore, the lack of symptoms should not preclude thorough evaluation.

Careful examination of the neck reveals the nature, location, and tenderness of the mass; fixation of the thyroid to surrounding tissue; and the presence of other cervical masses, which can be metastases or lymphadenopathy.

Benign masses are usually movable, soft, and nontender. Malignancy is associated with a hard nodule, fixation to surrounding tissue, and regional lymphadenopathy. See the image below.

A 12-year-old patient with an asymptomatic palpabl A 12-year-old patient with an asymptomatic palpable thyroid nodule noticed upon routine physical examination.

Suspicions of cancer rise in incidents of a true solitary thyroid nodule, especially if designated as cold on scintigraphy. Reported rapid growth or recurrent laryngeal nerve dysfunction found on examination may indicate malignancy and local infiltration.

Finally, if medullary carcinoma is suspected in conjunction with multiple endocrine neoplasia (MEN) 2B, multiple mucosal neuromas, marfanoid body habitus, and skeletal defects may also be evident.

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Causes

Many risk factors are associated with the development of thyroid nodules and cancer. A family history of thyroid disease, benign or malignant, significantly increases risk. Fowler et al found that a family history of thyroid disease was present in 41% of their patients with thyroid nodules. [10] A family history of endocrine tumors also has been shown to increase risk, especially in persons with MEN. Increased risk has been found in some endemic areas, although environmental reasons have not been elucidated fully. In the pediatric population, pubertal girls are more likely to develop a thyroid nodule, although the risk of malignancy in these individuals is lower than that in boys. Thyroid disease has also been associated with familial polyposis syndrome.

Exposure to certain carcinogens predisposes patients to the development of thyroid disease. Previous head and neck irradiation is the most obvious and well-known risk factor.

In the first half of the 20th century, head and neck irradiation was used widely for treating a number of benign conditions, including acne, tonsillar enlargement, thymic enlargement, and tinea capitis. During this period, the incidence of thyroid nodules in children and the risk of malignancy in the nodules were much higher.

In the 1950s, 70% of thyroid nodules in children harbored malignancy. Fortunately, widespread misuse of irradiation has ceased, and malignancy rates have fallen.

Irradiation is still a factor in children who have received therapeutic radiation for Hodgkin lymphoma, bone marrow transplants, or other malignancies or in those who have been exposed to unusual environmental radiation, such as the Chernobyl accident.

Thyroid tumors may occur as early as 5 years to as late as 40 years after radiation exposure, with a peak at 10-20 years after treatment. Radiation levels as low as 0.1 Gy have been demonstrated to increase the risk of cancer. Nuclear fallout exposure, such as that which occurred at Nagasaki, Hiroshima, and Chernobyl, also significantly increases risk. Children near Chernobyl were 62 times more likely to develop thyroid cancer after the Chernobyl incident than before it occurred. These tumors were especially aggressive, often occurring 4-6 years after exposure.

A history of other malignancy may also increase risk for thyroid cancer. Alkylating agents have been associated with the development of thyroid nodules and malignancy. In addition, thyroid cancer comprises 9% of all second malignancies, most often associated with Hodgkin lymphoma. The mean age at incidence of second malignancies is 20 years.

Several genetic markers are under investigation for their association with thyroid tumors. Papillary tumors are more likely to demonstrate abnormalities on chromosome arm 10q, whereas follicular tumors more often involve chromosome 3.

The ras proto-oncogene is present in 80% of follicular tumors and often is present in follicular adenomas. It is also found in 20% of papillary tumors, and the presence of p21 ras is considered a prognostic indicator.

The ret proto-oncogene is associated with papillary tumors and medullary cancer, both familial and nonfamilial. It may be induced directly by radiation exposure. The presence of ret mutations in patients with family histories of MEN 2 is an indication for prophylactic thyroidectomy.

Finally, mutations in the thyroid-stimulating hormone (TSH)-receptor gene have been associated with the development of papillary tumors. As genetic research continues, the actual cause of thyroid tumors may become more evident.

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