Thyroid noduleQuestion 1 definition of thyroid nodulesThyroid nodule is a kind of pathological changes caused by abnormal growth of thyroid
Question 1 definition of thyroid nodules
Thyroid nodule is a kind of pathological changes caused by abnormal growth of thyroid cells. Although it can be touched, but can not be confirmed in the ultrasound diagnosis of nodules can not be diagnosed as thyroid nodules. A nodule that was not found in the physical examination, and incidentally found in the imaging examination, was referred to as "thyroid nodule".
Question 2 prevalence of thyroid nodules
Thyroid nodules are common. In the general population by palpation of the detection rate of -7% was 3%, with high resolution ultrasound detection rate can be as high as 76% 20%-.
Question 3 assessment of thyroid nodules
5%-15%'s thyroid nodules are malignant, or thyroid cancer. There were significant differences in the quality of life (quality of life, QOL) and the medical costs associated with the clinical treatment of benign and malignant thyroid nodules. Therefore, the key point of thyroid nodule evaluation is to distinguish benign from malignant.
Clinical manifestations of 4 thyroid nodules
Most patients with thyroid nodules had no clinical signs. When combined with thyroid dysfunction, the clinical manifestations may occur. Some patients because of tissue around the nodules of oppression, the sound pressure, breathing, hoarseness / dysphagia and other symptoms of oppression.
The history and physical examination results were risk factors of thyroid carcinoma in childhood: head and neck radiation history or history of exposure to radioactive dust; the general history of radiation therapy; to have differentiated thyroid cancer (differentiated thyroid, cancer, DTC), medullary thyroid carcinoma (medullary thyroid, cancer, MTC) or multiple endocrine neoplasia type 2 (type MEN2), familial adenomatous polyposis and certain thyroid cancer syndrome (Cowden syndrome, Carney syndrome, Werner syndrome and Gardner syndrome) past history or family history; the male; the rapid growth of the nodules; with persistent hoarseness, voice pronunciation difficult, and can exclude vocal cord lesions (inflammation, polyps); the difficulty in swallowing or breathing difficulties; the irregular shape, adhesion with surrounding tissue fixation; 9 with lymph node pathology Sexual enlargement.
Question 5 laboratory examination of thyroid nodules
Serum thyroid stimulating hormone (TSH) levels were detected in all patients with thyroid nodules. Studies have shown that patients with thyroid nodules, such as the level of TSH is lower than normal, the proportion of malignant nodules are lower than those with normal or elevated TSH levels.
Thyroglobulin (Tg) is a specific protein produced by thyroid follicular epithelial cells. Many kinds of thyroid diseases can increase the levels of serum Tg, including differentiated thyroid cancer, goiter, thyroid tissue inflammation or injury, hyperthyroidism (hyperthyroidism), so serum Tg can not differentiate benign and malignant thyroid nodules.
Effect of ultrasound examination in 6 thyroid nodules in the evaluation
High resolution ultrasonography is the preferred method for the evaluation of thyroid nodules. The palpation examination showed the suspect, "thyroid nodules" shall be performed neck ultrasonography. The neck ultrasound confirmed that "thyroid nodules" really exists, determine the size, number, position and texture of thyroid nodules (solid or cystic), shape, boundary, envelope, calcification, blood supply and the relationship with the surrounding tissue and so on, while assessing the size, morphology and structure features of neck regional lymph node and lymph node.
Some ultrasonic signs are helpful to distinguish benign and malignant thyroid nodules. The following two kinds of thyroid nodule ultrasound changes almost all benign: pure cystic nodules; the multiple vesicles occupy more than 50% of nodule volume and spongy change nodules, 99.7% were benign. The possibility and ultrasonographic features of thyroid carcinoma following tips: 1 hypoechoic nodules; the nodule rich blood supply (normally TSH); the irregular shape and edge nodules, halo absence; the microcalcification, needle like scattered or clustered calcification; 5 accompanied by cervical lymph node ultrasound imaging abnormalities, such as lymph nodes were round, irregular or fuzzy, uneven internal echo, internal calcification, corticomedullary unclear boundaries, hiler disappeared or cystic degeneration etc.. The ability to differentiate between benign and malignant thyroid nodules by ultrasonography is associated with the clinical experience of the physician.
Question 7 thyroid scintigraphy in the evaluation of thyroid nodules
Limited by the resolution of the imaging system, thyroid scintigraphy was used to evaluate thyroid nodules with diameter > and 1cm. In the presence of a single (or multiple) nodule with a decrease in serum TSH, thyroid 131I or 99mTc radionuclide imaging can be used to determine whether a (or some) nodule has an independent uptake of "hot nodule"". Most of the hot nodules are benign and do not require fine-needle aspiration biopsy (fine needle aspiration biopsy, FNAB).
Question 8 the role of fine needle aspiration biopsy (FNAB) in the evaluation of thyroid nodules
The sensitivity of preoperative diagnosis of thyroid carcinoma by FNAB was 83% (65-98%), and the specificity was (72-100%). The positive predictive rate was (50-96%), and the false negative rate was 5% (1-11%). The false positive rate was 0-7%. FNAB is unable to distinguish thyroid follicular carcinoma and follicular cell adenoma. Preoperative FNAB examination may help to reduce unnecessary thyroid nodule surgery and help determine appropriate surgical procedures.
FNAB of thyroid nodules with diameter > and 1cm can be considered. But in the case of FNAB, not as a routine of thyroid radionuclide imaging confirmed independent uptake in the hot nodules; ultrasonic tips for pure cystic nodules; according to ultrasound imaging has been highly suspected malignant nodules.
Diameter < 1cm thyroid nodules, not recommended for routine FNAB. But if there are the following, can be considered under the guidance of ultrasound and FNAB: ultrasound showed nodular malignant signs; in patients with cervical lymph node imaging abnormalities; the childhood neck radiation history or the history of contact radiation pollution; thyroid cancer or thyroid cancer syndrome history or family history; the serum Ct (abnormally high levels of calcitonin).
Compared with palpation under FNAB, and the success rate of diagnosis of ultrasound guided FNAB were more accurate. In order to improve the accuracy of FNAB, can take the following methods: Based on multiple parts of the same nodule in repeated puncture; ultrasound signs of suspicious tissue; materials in solid parts of cystic nodules, and cystic fluid cytology. In addition, experienced operators and pathological diagnosis of physicians is also an important link to ensure the success rate and diagnostic accuracy of FNAB.
Lack of strong evidence for optimal follow-up frequency of thyroid nodules. Most thyroid benign nodules can be followed up every 6-12 months. Yet the treatment of suspected malignant or malignant nodules, can shorten the interval of follow-up. Medical history and physical examination should be performed at each visit. Thyroid function was also observed in some patients (who were initially diagnosed with thyroid dysfunction who underwent surgery, TSH suppression therapy, or 131I therapy).
If the nodule growth obviously during follow-up, we must pay special attention to whether the symptoms and signs of malignant nodules with tips (such as voice, hoarseness respiratory / dysphagia, tubercle fixation, cervical lymph node enlargement and ultrasonographic signs etc.). "Significant growth" refers to the nodule volume increased by more than 50%, or at least 2 diameters increase over 20% (and more than 2mm), then the indications of FNAB; for cystic nodules, according to the growth of the solid part determines whether it is FNAB.
Problem 9 treatment of benign thyroid nodules
Most benign thyroid nodules should be followed up regularly without special treatment. In a few cases, surgical treatment, TSH suppression therapy, 131I (radioiodine, RAI), or other treatment options may be selected.
10 surgical treatment of benign thyroid nodules
The following conditions may be considered for surgical treatment of thyroid nodules: there was significantly associated with nodules local compression symptoms; thyroid function, with hyperthyroidism, medical treatment is invalid; the tumor in the chest or mediastinal nodules; the growth of the clinical, consider a malignant tendency or with thyroid cancer risk factors. Due to the appearance or thought of excessive impact on normal life and strongly require surgery, can be used as a relative indication of surgery.
The principle of operation for benign thyroid nodules is: to complete the removal of thyroid nodules at the same time, as far as possible to retain normal thyroid tissue. Recommend prudent use of total or near total thyroidectomy type. The indications of the latter were as follows: the diffuse distribution of nodules in bilateral thyroid gland, resulting in difficult to retain more normal thyroid tissue. Preservation of parathyroid and recurrent laryngeal nerve during operation.
Question 11 non operative treatment of benign thyroid nodules
TSH suppression therapy principle is: the application of "euthyrox" will be the serum level of TSH inhibited to the lower limit of normal or even low limit, in order to inhibit TSH growth promoting effect on thyroid cells, reduce the purpose of thyroid nodules. Effect: in iodine deficiency area, TSH suppression therapy may help narrow nodules and prevent new nodules appear and narrow nodular goiter volume; in non iodine deficiency area, although TSH suppression therapy may also reduce the nodules, but its long-term curative effect is exact, the withdrawal may appear nodular regrowth; TSH suppression scheme (TSH control on the lower limit of the normal range, 0.4-0.6mUA) and TSH (TSH control scheme completely inhibited in < 0.1mUA) compared to reduce the volume efficiency of similar nodules. Side effects: long-term suppression of TSH in subclinical hyperthyroidism (reduced TSH, FT3 and FT4 normal), caused discomfort symptoms and some adverse reactions (such as heart rate, atrial fibrillation, left ventricular enlargement, increased myocardial contractility and diastolic dysfunction, etc.) caused by bone mineral density in postmenopausal women (BMD reduce). The pros and cons, do not recommend the routine use of TSH suppression therapy in the treatment of benign thyroid nodules; can be used in young patients with small nodular goiter; if you want to use, to target the TSH partial inhibition.