Thyroid nodules
(thyroid nodule)
Content
nGeneral description
nCategories
nDiagnosis
nTreatment
nSpecial Problems
Definition
nThyroid nodules may appear differently with different tests
Palpation: nodules are masses found in the thyroid region
Ultrasound: nodules are focal areas of abnormal echogenicity in the thyroid gland
inconsistent nodule findings between different tests
nThyroid nodules palpated on examination but not suggested by ultrasound
nNodules not palpated on examination but detected on ultrasound
nSingle nodule palpated on physical examination, but multiple nodules on ultrasound
Epidemiology
Prevalence of thyroid nodules in the general population: palpation 3-7%, ultrasound 20%-70%.
The majority of thyroid nodules are benign and only 5% are malignant.
Etiology and classification
According to the etiology, they are classified as
nProliferative nodular goiter
nNeoplastic nodules: benign tumors, malignant tumors
n cysts
nInflammatory nodules
Diagnosis
nCore: identification of benign and malignant nodules.
nDetailed history taking and comprehensive physical examination are the basis for correct diagnosis.
Clinical manifestations
nFound on physical examination or ultrasonography;
Most of them are asymptomatic;
Very few have local pressure;
A few have abnormal thyroid function, hyperthyroidism or hypothyroidism.
Medical history
nFocus on.
nage
nGender
nHistory of radiographic treatment of the head and neck
nNodule size, growth rate
nLocal symptoms
nSymptoms related to abnormal thyroid function
nFamily history: thyroid tumor, medullary thyroid carcinoma, MEN type 2, familial polyposis, Cowden’s disease, and Gardner’s syndrome.
Physical examination
nThe focus should be on.
nNumber, size, texture, mobility, tenderness, and local lymph node enlargement of nodules.
Clinical evidence suggesting the possibility of malignant lesions
nHistory of treatment with neck radiography
n Family history of medullary thyroid carcinoma or MEN2
n Age less than 20 years or more than 70 years
nMale
n Significant increase in size of the nodule over a short period of time
nSymptoms of local compression, including persistent hoarseness, dysphonia, dysphagia, and dyspnea
nNodules are hard, irregularly shaped, and fixed
nWith enlarged lymph nodes in the neck
Laboratory tests
nThyroid function tests
All patients with thyroid nodules should have serum TSH and thyroid hormone levels measured.
The majority of patients with malignant nodules have normal thyroid function.
If serum TSH is below normal and nuclear imaging suggests a high-functioning nodule, the nodule is almost always benign.
Serum TPOAb and TgAb tests
n are clinical diagnostic indicators of Hashimoto’s thyroiditis.
The diagnosis of Hashimoto’s thyroiditis still does not completely exclude the possibility of malignancy, and a few cases of Hashimoto’s thyroiditis may be combined with papillary thyroid cancer or thyroid lymphoma.
Measurement of thyroglobulin (Tg) levels
The measurement of Tg is not helpful in identifying benign or malignant nodules.
Measurement of serum calcitonin level
It has diagnostic significance for medullary carcinoma. Those with family history of medullary thyroid carcinoma or family history of MEN2 should have their serum calcitonin levels measured in the basal or stimulated state.
Ancillary tests
High-resolution thyroid ultrasonography
nNuclear imaging of thyroid gland
MRI and CT of the thyroid
Fine needle aspiration cytology biopsy (FNAC) of the thyroid
High-resolution thyroid ultrasound
It is the most sensitive test for evaluating thyroid nodules.
It can be used not only to determine the nature of the nodule, but also to localize, puncture, treat and follow up on thyroid nodules under ultrasound guidance.
This test is required for all patients suspected of having thyroid nodules or existing thyroid nodules.
The report should include the location, morphology, size, number of nodules, nodule margins, internal structure, echogenic features, blood flow status and cervical lymph nodes.
Features of high resolution thyroid ultrasound suggestive of nodule malignancy
Microcalcifications;
Irregular nodule margins;
nDisturbance of blood flow signal within the nodule
nEvaluation.
nHigh specificity of all three features, >80%, but low sensitivity, 29%-77.5%.
nOne feature alone is not sufficient to diagnose malignant lesions.
nBut the sensitivity of diagnosing malignant disease increases to 87%-93% when more than 2 features are present at the same time or when one of the features is present in hypoechoic nodules.
Features of high-resolution thyroid ultrasonography suggestive of nodule malignancy
nHypoechoic nodules that invade the outer thyroid envelope or the muscles surrounding the thyroid gland;
n Hypoechoic nodules with enlarged cervical lymph nodes, with loss of lymph node portal structures, or cystic changes, or microcalcifications in the lymph nodes, or disturbances in blood flow signals.
Thyroid nuclear imaging
The only imaging method that can evaluate the functional status of nodules.
The nodules can be classified as “hot nodules”, “warm nodules” and “cold nodules” according to their ability to take up radionuclides.
The percentage of “hot nodules” is 10% and the percentage of “cold nodules” is 80%.
Ninety-nine percent of “hot nodules” are benign, and malignant nodules are extremely rare;
The rate of malignancy in “cold nodules” is 5%-8%. Therefore, the use of “cold nodules” to determine the benignity or malignancy of thyroid nodules is not very helpful.
This method is used for thyroid nodules combined with hyperthyroidism or subclinical hyperthyroidism to determine whether the nodule is a “hot nodule”.
It is worth noting that when the nodule is cystic or has a thyroid cyst, the thyroid nucleus may also appear as a “cold nodule”. This should be analyzed together with the ultrasound findings of the thyroid gland.
MRI and CT of the thyroid
MRI or CT are less sensitive than ultrasound in detecting thyroid nodules and determining the nature of the nodules, and are more expensive. Therefore, it is not recommended for routine use.
nIt has particular diagnostic value in assessing the relationship of thyroid nodules to surrounding tissues, especially for the detection of retrosternal goiter.
Fine needle aspiration cytology biopsy of the thyroid (FNAC)
n is the most reliable and valuable diagnostic method for identifying benign and malignant nodules
Sensitivity 83%, specificity 92%, accuracy 95% as reported in the literature
FNAC should be performed in all cases of suspected malignant changes
FNAC can be used to identify the cytological type of the cancer before surgery and help determine the surgical plan
It is worth noting that FNAC cannot differentiate follicular carcinoma from follicular cell adenoma
Some points worth noting
The benignity or malignancy of nodules is not related to the size of the nodule, and malignancy is not uncommon in nodules less than 1.0 cm in diameter;
nThe benignity or malignancy of nodules is not related to the palpability of nodules;
nThe benignity or malignancy of nodules is not related to whether the nodules are single or multiple;
nThe benignity or malignancy of nodules is not related to whether the nodules are combined with cystic lesions.
Treatment
Basis
The choice of treatment should depend on the characteristics of the thyroid ultrasound and the results of FNAC.
Treatment
nTreatment of malignant thyroid nodules
Management of benign nodules
Management of suspected malignant and undiagnosed thyroid nodules
nManagement of thyroid nodules in children
Management of thyroid nodules during pregnancy
Management of malignant thyroid nodules
The majority of malignant thyroid tumors require surgery.
Undifferentiated thyroid cancer is highly malignant and almost all of them have distant metastases at the time of diagnosis, so surgery alone is difficult to achieve the treatment purpose.
nThyroid lymphoma is sensitive to chemotherapy and radiotherapy, so once diagnosed, chemotherapy or radiotherapy should be used.
Management of benign nodules
nThe vast majority of patients with benign thyroid nodules do not require specific treatment.
nFollow up is required, every 6 months – 12 months.
nThyroid ultrasonography and repeat FNAC if necessary.
nOnly a small number of patients require treatment such as surgery, medications and PEI.
Several treatments for benign nodules
nL-T4 suppression therapy
nSurgical treatment
nUltrasound-guided percutaneous alcohol injection (PEI)
nRadioactive 131 iodine therapy
L-T4 suppression therapy
nObjective: To shrink existing nodules and prevent the creation of new nodules.
nOverall effect is not satisfactory
nAdverse effects are clear
nNot recommended for widespread use, only for a few benign thyroid nodules.
L-T4 suppression therapy
nApplicable to
nLiving in an iodine-deficient area;
nNodules are small in size and young;
nNodule function is involuntary;
L-T4 inhibition therapy
nNot suitable for.
nSerum TSH levels