A thyroid nodule is one or more abnormal structural masses in the thyroid gland. Most patients with thyroid nodules have no clinical symptoms and are often discovered unintentionally by themselves or by physicians during physical examinations or, more often, incidentally during ultrasound or other ancillary examinations.
According to the 2010 Chinese Epidemiological Sample Survey, the total prevalence of thyroid nodules in the population is 18.6%. This large number is not only due to the increased incidence of the disease, but also due to the increased emphasis on health and the popularity of medical checkups, especially the inclusion of thyroid ultrasound as a routine part of health checkups. This has made thyroid nodules, which used to be “hidden in the dark”, “famous to the world”.
Statistics show that about 95% of thyroid nodules are benign and about 5% are malignant (i.e. thyroid cancer).
First, it is important to understand whether there are coexisting risk factors for thyroid cancer, including.
① history of head and neck radiation exposure or radioactive fallout exposure during childhood.
② history of systemic radiation therapy.
③ previous history or family history of thyroid cancer, multiple endocrine adenomatosis type 2 (MEN2), etc.
④Male.
⑤ rapid nodule growth.
⑥with persistent hoarseness and dysphonia, and exclude vocal cord lesions.
(vii) with dysphagia or dyspnea.
⑧ irregular shape of the nodule and fixed adhesion to surrounding tissues.
⑨ with pathological enlargement of lymph nodes in the neck.
Of course, having high-risk factors is not the same as being a tumor. The focus should be on completing the following tests.
1. All patients with thyroid nodules should have their serum thyroid stimulating hormone (TSH) levels tested.
In patients with thyroid nodules, the risk of papillary thyroid cancer increases as TSH levels increase. If the nodule is large and TSH is decreased, thyroid nuclide imaging is recommended to determine if the nodule has autonomic uptake. Other blood indicators, such as calcitonin >100 pg/ml, suggest that medullary thyroid carcinoma may be high, but its screening significance is limited due to its low specificity. Another commonly used indicator, thyroglobulin (Tg), is not recommended for benign and malignant differentiation of nodules because a variety of thyroid diseases can cause elevated Tg levels.
2. All patients with thyroid nodules should undergo ultrasound examination of the neck.
Thyroid ultrasound can confirm the presence of nodules and determine their size, number, location, texture (solid or cystic), shape, borders, calcification, blood supply and relationship to surrounding tissues. It can also assess the presence and size of lymph nodes in the neck region. If the ultrasound reports: a purely cystic nodule, or a nodule consisting of multiple small vesicles occupying more than half of the nodule volume with spongy changes. Please be assured that this will almost certainly confirm a benign diagnosis.
If the ultrasound report contains: (1) a solid hypoechoic nodule; (2) a nodule with an abundant blood supply (combined with normal TSH); (3) a nodule with irregular morphology and margins and absent halo; (4) microcalcifications, pinpoint diffuse or clustered calcifications; (5) an abnormal ultrasound image of the cervical lymph nodes, such as a rounded lymph node with irregular or blurred borders, uneven internal echogenicity, internal calcifications, poorly demarcated corticomedullary, or cystic changes. In these cases, thyroid cancer may be associated with the loss of lymphatic gates or cystic changes. In these cases, the likelihood of thyroid cancer is increased.
However, in fact, benign and malignant nodules can coexist at the same time, and it is no longer reliable to distinguish benign and malignant nodules based on the characteristics of single or multiple nodules.
3. Fine needle aspiration biopsy (FNAB) of the thyroid is the most sensitive and specific method for assessing the benignity and malignancy of nodules.
Whether a nodule is benign or malignant, the gold standard of pathology can be obtained directly through a puncture biopsy. However, FNAB is after all an invasive operation and is indicated only when the following conditions are met.
① thyroid nodules >1 cm in diameter.
② diameter <1 cm but combined with: history of radiation exposure to the neck or radiation contamination exposure in childhood, history or family history of thyroid cancer or thyroid cancer syndrome, suspected malignancy on ultrasonography, with abnormal ultrasound images of the lymph nodes in the neck, positive PET imaging, and abnormally elevated calcitonin levels.
In conclusion, the more expensive and more tests are not better. For thyroid nodules, CT and MRI are not superior to ultrasound in identifying benign and malignant nodules, and they are not recommended as routine tests to evaluate thyroid nodules.
If it is finally clear that a thyroid nodule is benign, what happens next?
For most benign thyroid nodules, no specific treatment is required. Routine treatment of benign thyroid nodules with non-surgical methods, including TSH suppression therapy, radioactive iodine therapy, percutaneous anhydrous alcohol injection, percutaneous laser ablation and radiofrequency ablation, is not recommended. Follow-up visits are recommended at 6-12 month intervals; if malignancy is suspected, the follow-up interval should be even shorter.
Surgical treatment needs to be considered when benign thyroid nodules are combined with
(i) the presence of local pressure symptoms clearly associated with the nodule.
(ii) Combined hyperthyroidism and failure of medical treatment.
(iii) Ectopic masses located behind the sternum or within the mediastinum.
④Progressive growth of the nodule.
⑤ Clinical consideration of malignant tendency or combined with high risk factors for thyroid cancer.
A strong request for surgery due to appearance or excessive ideological concerns affecting normal life is also a relative indication for surgery. After all, a disease of the heart is also a disease and must be treated!
These are the general recommendations for patients with thyroid nodules, and there are two special groups to look over.
1. Thyroid nodules in children
The evaluation and treatment of thyroid nodules in children is basically the same as in adult patients. It should be noted that the proportion of malignant nodules in children is higher than that in adults, about 20%, and the chances of multifocal, lymphatic and distant metastases are high. If the child also has a family history of combined medullary thyroid cancer or MEN2, RET mutation testing is recommended. In addition, CT neck examination should be performed carefully in children.
2.Thyroid nodules in pregnant women
The evaluation and management of thyroid nodules in pregnant women is basically the same as in non-pregnant women, but nuclide imaging and radioactive iodine therapy are prohibited. If the nodule is malignant, it is safer to perform the surgery in the third to sixth month of pregnancy, otherwise it should be performed at a later date after delivery.
When a thyroid nodule is found, there is no need to be suspicious and scare yourself, nor should you take it lightly and let it go. In short, thyroid nodules are highly prevalent and the majority are benign. It is important to evaluate the nodules for benignity and malignancy.