Cold nodules

Introduction Thyroid adenoma: mostly single, slow growth, asymptomatic. The thyroid scan is a "warm nodule." If it is a toxic adenoma, it shows "hot nodules." Adenomas can also develop hemorrhage, necrosis and liquefaction as "cold nodules." The cause of thyroid tumors is unknown and may be related to gender, genetic factors, radiation exposure, TSH over-stimulation, and possibly endemic goiter disease. Most of the patients are women, often under the age of 40, usually a single nodule in the thyroid gland. The course of the disease is slow, mostly in months to years or even longer, and the patient is found to have a neck mass due to a slight discomfort or without any symptoms.

Cause

(1) Causes of the disease

The cause of thyroid tumors is unknown and may be related to gender, genetic factors, radiation exposure, TSH over-stimulation, and possibly endemic goiter disease.

1. Gender: The incidence of thyroid tumors in women is 5-6 times that of men, suggesting that gender may be related to the pathogenesis, but no evidence of estrogen-stimulated tumor cell growth has been found.

2. Oncogene: The expression of the oncogene c-myc can be found in thyroid adenomas. Activating mutations and overexpression of codons 12, 13, and 61 of the oncogene H-ras can also be found in adenomas. Mutations in proteins involved in the TSH-G protein adenine cyclase signaling pathway, including extracellular and transmembrane mutations in the transmembrane domain of the TSH receptor and stimulatory GTP-binding proteins, can also be found in highly functional adenomas. mutation. All of the above findings indicate that the onset of adenoma may be related to oncogenes, but the above mutations are only found in a small number of adenomas.

3. Familial tumors: Thyroid adenomas can be found in some familial tumor syndromes, including Cowden's disease and Catney's disease.

4. External radiation: In the early years, the incidence of thyroid cancer increased by about 100 times in the head, neck and chest who had been treated with X-ray, and the incidence of thyroid adenoma was also significantly increased.

5. TSH over-stimulation: Some patients with thyroid adenoma can find that their blood TSH levels are increased, which may be related to their onset. It was found that TSH stimulated 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 cysts and a complete capsule; the microscope image is divided into five subtypes:

1 embryonic adenoma.

2 fetal adenomas.

3 colloidal 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 adenomas do not exist, and that papillary structures are found to be diagnosed as low-grade papillary adenocarcinoma, classified according to the condition of the nipple branch. Papillary adenomas are generally considered to be characterized by papillary structures and cystic tendencies.

(two) 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, and some can be cystic. The cut surface is yellowish white or yellowish brown due to different tissue structure. Some cut surfaces are finer, and some cut surfaces are honeycomb or fine granular. The tumor can be necrotic, fibrotic and calcified into cystic changes.

2. Under histological observation, the histological types of thyroid adenomas can be divided into follicular adenomas, papillary adenomas and atypical adenomas, which have some common histological features and different Pathological manifestations.

(1) Common histological features:

1 often a single nodule with a complete fibrous envelope.

2 The tissue structure of the tumor is different from that of the surrounding thyroid tissue.

3 The internal structure of the tumor has relative consistency (except for changes due to degeneration).

4 There is 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, it is divided into:

A. Embryonic adenoma: consists of solid cell nests and cell cords with no obvious follicles and colloid formation. The tumor cells are mostly cuboidal, small in size and consistent in cell size. Less cytoplasm, basophilic, less clear boundaries; large nuclei, more chromatin, located in the center of the cell. There are few interstitials and many edema. 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 gelatin. The follicular cells are small, cuboidal, with deep staining of the nucleus, and their morphology, size and staining may vary. The follicles are dispersed in the connective tissue of loose edema. There are abundant thin-walled blood vessels in the interstitium, and common hemorrhage and cystic changes.

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

D. Simple adenoma: follicular morphology and glial content are similar to normal thyroid. However, the follicles are arranged closely, are polygonal, and have few interstitials.

F. Eosinophilic tumor: also known as Hurthle cell tumor. The tumor cells are large and polygonal, and the cytoplasm contains eosinophilic granules arranged in strips or clusters, 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. The morphology of the cells is similar to that of the normal quiescent thyroid epithelium. The nipple is short, the branches are few, and sometimes the nipples contain glial cells. The nipples protrude into the sacs of different sizes, and the cavity is rich in colloid. The tumor cells are small, consistent in morphology, and have no obvious morphological and mitotic figures. Among thyroid adenomas, those with papillary structures have a greater malignant tendency.

3 atypical adenoma: less common. The adenoma envelope is intact, the texture is tough, and the cut surface is fine without gelatinous luster. Microscopically, the cells are rich and dense, often in the form of patches, nests, irregular structures, and do not form follicles. There is very little interstitial. The cells have obvious heteromorphism, inconsistent shape and size, and can be rectangular or 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 there is no infiltration of the capsule, blood vessels and lymphatic vessels.

an examination

Related inspection

Tumor-associated antigen tumor marker detection

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. Individual circular nodules can be touched in the thyroid gland, and multiple are individual. The surface is smooth, the boundary is clear, there is no adhesion to the skin, and it moves up and down with swallowing. The texture is different, the solid is soft, and the cystic is hard. Some patients suddenly increased due to tumor hemorrhage, local pain and tenderness, and symptoms of hyperthyroidism. When the tumor is enlarged, it can cause symptoms of compression of adjacent organs.

3. The radionuclide scan can be warm nodule and the cystic person is cold nodule. The 131 iodine rate of thyroid absorption is generally normal.

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

5. The thyroid function test is normal.

6. There is no swelling in the neck lymph nodes.

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

Differential diagnosis

Differential diagnosis of cold nodules:

1, hot nodules: the ability to absorb iodine at the nodules is greater than normal thyroid tissue. Mostly benign autonomous functional thyroid adenoma. Due to the secretion of a large amount of thyroid hormone at the nodules, the secretion of TSH is inhibited, resulting in a decrease in 131I absorption in thyroid tissue other than nodules. Therefore, around the nodule, even all thyroid tissue has no absorption of 131I.

2. Warm nodules: The radiation intensity at the nodules is not different from other thyroid tissues. Most are benign tumors.

3, cold nodules: nodular tissue does not absorb iodine, so there is no radioactivity at the nodules. This type of knot saves about 20% of cancer. For a single hair, the boundary with the surrounding tissue is not very clear, the possibility of cancer is greater. Combined with the determination of serum calcitonin, the diagnosis rate can be improved. Cool nodules are more common in the undifferentiated thyroid cancer, medullary carcinoma, thyroid cystic changes and subacute thyroiditis in the acute phase.

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