A thyroid nodule is a mass or masses of abnormal tissue structure in the thyroid gland due to various causes. A variety of thyroid disorders can appear in the form of thyroid nodules. With a prevalence of 3% to 7% in the general population and a detection rate of 20% to 50% on ultrasonography, the key to clinical diagnosis is to identify the nature of the nodule.
In the diagnosis, detailed history taking and a thorough physical examination are important. History taking should focus on the patient’s age, gender, history of head and neck radiation exposure, nodule size and growth rate, local symptoms, symptoms related to abnormal thyroid function and family history related to thyroid cancer. The physical examination focuses on the number, size, texture, mobility, tenderness, and local lymph node enlargement of the nodules. Clinical clues that suggest a nodule may be malignant include a history of radiation exposure to the neck; a family history of medullary thyroid cancer or multiple endocrine adenomatosis type 2 (MEN2); a patient younger than 20 years or older than 70 years; a male; a nodule that is significantly larger and >2 cm in diameter within a short period of time; symptoms of local compression such as persistent hoarseness, dysphonia, dysphagia, or dyspnea; a nodule that is hard, regular in shape, and fixed; and a nodule that is associated with a local lymph node swelling. The nodes are hard, irregular in shape and fixed; accompanied by enlarged lymph nodes in the neck. Yu Nianfeng, Department of Surgery, Taonan City Hospital of Traditional Chinese Medicine
Question 1: What laboratory tests are helpful in determining the nature of nodules?
All patients with nodules should closely follow the measurement of serum TSH level and serum thyroid hormone level; serum anti-TPOAb and anti-TgAb tests are helpful in diagnosing autoimmune thyroid diseases, especially Hashimoto’s thyroiditis; measurement of serum calcitonin level is diagnostic for medullary carcinoma, and those with family history of medullary thyroid carcinoma or family history of MEN2 should have their serum calcitonin level measured in the basal or stimulated state. The serum calcitonin level should be measured in the basal or stimulated state. A variety of thyroid disorders can lead to elevated serum Tg levels. Determination of Tg is not helpful in identifying the benign or malignant nature of the nodule.
Question 2: Which diagnostic imaging tests should be performed?
High-resolution ultrasonography of the thyroid gland is the most sensitive test to detect thyroid nodules. It can also be used to determine the nature of the nodule, as well as to localize, puncture, treat and follow up on thyroid nodules under ultrasound guidance. Therefore, thyroid ultrasound should be performed in all patients suspected of having thyroid nodules, as well as in patients with thyroid nodules found on physical examination. ECT is the only imaging method that can evaluate the functional status of nodules. Nodules can be classified as “hot nodules”, “warm nodules” and “cold nodules” according to their ability to take up radionuclides. This method is used for thyroid nodules with hyperthyroidism or subclinical hyperthyroidism to determine if the nodule is a “hot nodule”. MRI or CT are less sensitive than thyroid ultrasound in detecting thyroid nodules and determining the nature of the nodules, and are more expensive. They should not be used routinely. However, assessment of the relationship of the thyroid nodule to the surrounding tissues, especially for the detection of retrosternal goiters, has particular diagnostic value.
Fine needle aspiration cytology biopsy (FNAC) of the thyroid gland is the most reliable and valuable diagnostic method for identifying benign and malignant nodules, with a diagnostic sensitivity of 83%, specificity of 92%, and accuracy of 95%. FNAC should be performed if malignant changes are suspected.
Question 3: How should thyroid nodules be treated after the diagnosis is clear?
The majority of malignant thyroid tumors require surgery as the first choice of treatment. Most benign thyroid nodules do not require specific treatment, but patients with benign thyroid nodules need to be followed up every 6 to 12 months. Only a few patients require surgery, thyroxine suppression therapy and PEI therapy