Thyroid adenoma

Introduction to thyroid adenoma Thyroid adenoma (thyroidadenoma) is a benign tumor originating from thyroid follicular cells and is the most common thyroid benign tumor of the thyroid gland. At present, the disease is considered to be mostly monoclonal, which is caused by stimulation similar to thyroid cancer, and occurs in the active phase of thyroid function. Clinically, there are two kinds of follicular and papillary solid adenomas. The former is more common. It is often a single nodule with clear boundaries in the thyroid sac and a complete capsule. The size is less than 1~10cm. The disease is sporadic in the country and is more common in endemic goiter areas. basic knowledge The proportion of illness: 15.6%-28.7% Susceptible people: no specific population Mode of infection: non-infectious Complications: superior vena cava syndrome

Cause of thyroid adenoma

Oncogene (30%):

The expression of the oncogene c-myc can be found in thyroid adenomas. Activating mutations and overexpression of the 12, 13, and 61 codons of the oncogene H-ras can also be found in adenomas. TSH- can also be found in high-function adenomas. Mutations in proteins involved in the G protein adenine cyclase signaling pathway, including mutations in the extracellular and transmembrane segments of the TSH receptor transmembrane domain and mutations in stimulatory GTP-binding proteins, all of which indicate the onset of adenoma May be related to oncogenes, but the above mutations are only found in a small number of adenomas.

TSH over-stimulation (40%):

Some patients with thyroid adenoma may find that their blood TSH levels are increased, which may be related to their pathogenesis. It is found that TSH can stimulate normal thyroid cells to express the pro-oncogene c-myc, thereby promoting cell proliferation.

(1) Follicular adenoma

Typical follicular adenomas are substantially circular or elliptical, with a few cystic and complete capsules; the microscope image is divided into five subtypes: 1 embryonic adenoma, 2 fetal gland Tumor, 3 gland adenoma, 4 eosinophilic adenoma or Hurthle cell tumor, 5 atypical adenoma.

(2) papillary adenoma

It is a rare benign epithelial tumor. Some pathologists believe that benign papillary adenoma is absent. It is diagnosed as a papillary adenocarcinoma with a papillary structure, according to the nipple branching. Classification, it is generally believed that papillary adenomas are characterized by papillary structures and cystic tendencies.

Pathogenesis

1. Gross shape: generally a single round or elliptical mass with complete capsule, smooth surface and tough texture. Most of them are solid masses with a diameter between 1.5 and 5 cm. Some of them can be cystic. The structure is different, but yellow-white or yellow-brown, some of the cut surface is more delicate, and some of the cut surface is honeycomb or fine granular, the tumor can be necrotic, fibrotic, calcified into cystic changes.

2, histology: microscopic observation found that thyroid adenoma has different histological types, can be divided into follicular adenoma, papillary adenoma and atypical adenoma, they have some common histological features, and have their own Different pathological manifestations.

(1) Common histological features: 1 often a single nodule with a complete fibrous envelope, 2 tumor tissue structure is different from surrounding thyroid tissue, 3 tumor internal structure is relatively consistent (except for changes due to degeneration) 4 has an extrusion phenomenon on the surrounding tissue.

(2) Histological manifestations of various adenomas:

1 follicular adenoma: is the most common type of benign thyroid tumor, according to the tissue morphology of the tumor:

A. Embryonic adenoma: consists of solid cell nests and cell cords, no obvious follicles and colloid formation. Tumor cells are mostly cuboidal, small in size, uniform in cell size, less cytoplasm, and basophilic. The boundary is not clear; the nucleus is large, the chromatin is much, and it is located in the center of the cell. There are few interstitial, many edema, and the capsule and blood vessels are not invaded.

B. Fetal adenoma: mainly composed of small and uniform small follicles, follicles may or may not contain colloid, follicular cells are small, cuboidal, and the nucleus is deeply stained, its shape and size And staining can be mutated, the follicles are dispersed in the connective tissue of loose edema, the interstitial is rich in thin-walled blood vessels, common bleeding and cystic changes.

C. Gummy adenoma: also known as giant follicular adenoma, the most common, tumor tissue consists of mature follicles, its cell morphology and colloidal content are similar to normal thyroid, but the size of the follicles is very different, arranged closely, can also be fusion Become a capsule.

D. Simple adenoma: follicular morphology and glial content are similar to normal thyroid, but the follicles are closely arranged, polygonal, with few interstitial.

E. Eosinophiloma: Also known as Hurthle cell tumor, the tumor cells are large and polygonal, and the cytoplasm contains eosinophilic particles arranged in a strip or cluster, occasionally into follicular or papillary.

2 papillary adenoma: benign papillary adenoma is rare, mostly cystic, it is also known as papillary cystadenoma, the nipple is composed of a single layer of cubic or low columnar cells covering the blood vessels and connective tissue, cell morphology and normal static The thyroid epithelium is similar, the nipple is short, the branches are few, and sometimes the nipple contains glial cells. The nipples protrude into the cysts of different sizes. The cavities are rich in colloids, the tumor cells are small, and the morphology is consistent. Obvious pleomorphism and mitotic figures, thyroid adenomas, with papillary structures have a greater malignant tendency.

3 atypical adenoma: less common, adenoma capsule intact, tough texture, fine cut surface without glial luster, microscopic cells are rich, dense, often in the form of patches, nested, irregular structure, more than Follicles are formed, the interstitial is very small, the cells have obvious heteromorphism, shape and size are inconsistent, can be rectangular, fusiform; the nucleus is irregular, the staining is deep, and the mitotic image is also visible, so it is often suspected to be cancerous, but no Infiltration of the capsule, blood vessels and lymphatic vessels.

Thyroid adenoma prevention

Because the cause of thyroid adenoma is still unclear, there are no good preventive measures. Early detection of this disease, early treatment is the best measure to prevent the development of the disease.

Prevention of endemic goiter disease may be effective in preventing this disease.

Thyroid adenoma complications Complications of superior vena cava syndrome

Post-sternal thyroid adenomas may cause dyspnea and superior vena cava compression after compression of the trachea and large blood vessels.

Symptoms of thyroid adenoma Common symptoms Thyroid gland and smooth... There is a lump under the cold nodule throat, difficulty breathing, hoarseness, hard cold nodules, pain

Most of the patients are women, usually under 40 years old, usually single nodules in the thyroid gland, the course of the disease is slow, most of them are several months to years or even longer, the patient is found or has no symptoms due to slight discomfort. Most of the neck masses were found to be single-shot, round or elliptical, with smooth surface, clear boundary, firm texture, no adhesion to surrounding tissues, no tenderness, and can move up and down with swallowing. The diameter of the tumor is usually several centimeters. Large people are rare, huge tumors can produce signs of compression of adjacent organs, but do not invade these organs, a small number of patients due to intratumoral hemorrhage tumors suddenly increased, accompanied by pain; some tumors will gradually absorb and shrink; some can occur cystic Change, longer history, often due to calcification to make the tumor hard; some can develop into functional autonomous adenoma, and cause hyperthyroidism, papillary cystic adenoma sometimes due to cystic vascular rupture and intracapsular hemorrhage, at this time The tumor volume can be rapidly increased in a short period of time, and there is a local painful feeling.

Some thyroid adenomas may develop cancer, and the cancer rate is 10% to 20%. The following conditions should be considered: 1 The tumor may increase rapidly in the near future, 2 the tumor activity is limited or fixed, and 3 hoarseness occurs. Symptoms such as difficulty breathing, 4 tumors are hard, rough surface, 5 cervical lymphadenopathy.

Thyroid adenoma can be divided into two types of follicular adenoma and papillary cystic adenoma. The former is more common, the cut surface is light yellow or deep red, and has a complete capsule. The latter is rarer than the former, and its characteristics are papillary. Protuberances are formed, mostly single nodules, which develop slowly and have a long course of disease.

Examination of thyroid adenoma

Serum T3 and T4 were in the normal range, and all functional tests were normal.

1, B-ultrasound: can further confirm the mass is solid or cystic, the edge is clear, the mass is mostly single, but also multiple, for 2 to 3 small masses, the same side of the gland is also increased The solid is an adenoma, and the cystic is a thyroid cyst.

2, isotope scan: 131I scan shows that the thyroid is a warm nodule, cystadenoma can be a cold nodule, thyroid radionuclide scan is mostly warm nodules, can also be hot nodules or cold nodules.

3, neck X-ray: If the tumor is larger, the positive lateral slice can be seen that the trachea is compressed or displaced, and some tumors can be seen with calcified images.

4, thyroid lymphography: shows a circular filling defect in the network structure, the edge of the rule, the surrounding lymph nodes are fully developed.

Diagnosis and diagnosis of thyroid adenoma

diagnosis

The diagnosis of thyroid adenoma is mainly based on medical history, physical examination, isotope scan and "B" type ultrasound.

1, painless mass in front of the neck, early asymptomatic, individual swallowing discomfort or infarction, more common in middle-aged women.

2, the thyroid can touch a single round nodule, individual multiple, smooth surface, clear boundaries, no adhesion to the skin, moving up and down with swallowing, texture is different, the soft is solid, the cystic is hard, some patients Sudden increase in tumor hemorrhage, local pain and tenderness, and transient hyperthyroidism, which can cause symptoms of adjacent organ tissue after tumor enlargement.

3, radionuclide scanning can be "warm nodules", cystic people are "cold nodules", thyroid absorption 131 iodine rate is generally normal.

4, B-mode ultrasound examination can distinguish solid or cystic adenoma.

5, thyroid function test is normal.

6, the neck lymph nodes are not swollen.

7, after taking thyroid hormone for 3 to 6 months, the mass does not shrink or more prominent.

Differential diagnosis

Thyroid adenoma should be differentiated from other thyroid nodules.

1, nodular goiter: thyroid adenoma is mainly differentiated from nodular goiter, although the latter has a single nodule, but the thyroid is mostly swollen, in this case easy to identify, in general, adenoma The single nodular nodules are still single, and the nodular goiter becomes multiple nodules after a long-term course of disease. In addition, the goiter-prone areas are diagnosed as nodular goiter, and non-endemic areas are diagnosed as thyroid glands. Tumor, in pathology, the single nodule of thyroid adenoma has a complete capsule with clear boundaries, while the nodular nodule of nodular goiter has no complete capsule and the boundary is not clear.

2, thyroid cancer: thyroid tumor should also be differentiated from thyroid cancer, the latter can be expressed as thyroid hard nodules, uneven surface, unclear boundaries, cervical lymph nodes, and may be accompanied by hoarseness, Horner's syndrome Etc. The following points can be used as a reference for the identification of thyroid cancer: 1 children or men over the age of 60 should consider the possibility of thyroid cancer, and thyroid adenomas occur mostly in women under 40 years of age.

2 thyroid cancer nodules surface is uneven, the texture is hard, the activity is small when swallowing, and grows faster in a short period of time, sometimes although the thyroid nodules are small, but the ipsilateral neck has enlarged lymph nodes, thyroid gland The surface of the tumor is smooth, the texture is soft, the upper and lower movements are large when swallowing, the growth is slow, and there is no swelling of the neck lymph nodes.

3131 iodine scan or radionuclide gamma thyroid cancer mostly manifests as cold nodules, while thyroid adenomas can be characterized by warm nodules, cold nodules or cold nodules, and cold nodules with "B" ultra-examination are mostly sacs. Sexual performance.

4 In the operation, thyroid cancer showed no adhesion or adhesion to the surrounding tissue, while thyroid adenoma had a complete capsule and the surrounding thyroid tissue was normal.

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