Thymic carcinoid

Introduction to thymic carcinoid Thymic carcinoid tumor is a kind of thymic neuroendocrine cell tumor. The thymus neuroendocrine cell tumor is divided into two categories, and the other is thymocyte small cell carcinoma. The morphological and ultrastructural features of thymic neuroendocrine tumors and the secretion of biochemical substances secreted by APUD cells from other parts of the body are supportive of thymic neuroendocrine tumor cell tumors originating from nerve ridge argyrophil cells (Kultschitzky cells). . basic knowledge The proportion of illness: 0.003%--0.005% Susceptible people: no special people Mode of infection: non-infectious Complications: myasthenia gravis

Thymic carcinoid cause

Cause:

Thymic carcinoid tumors are a class of independent thymic tumors that differ from epithelial thymoma in histology, electron microscopy, and clinical features.

Pathology

The histological features of thymus carcinoid under light microscope are the same as those of other parts of the body. The tumor cells are small and regular, and the nucleus is round or elliptical. The cytoplasm contains small particles of eosinophils and tumors. The cells are arranged in a bundle or band-like organ structure. The structure of the rosette and the necrosis of the tumor center can be seen. A large number of neuroendocrine granules can be seen under electron microscope. Immunohistochemistry: NSE(+), Leu-7(+) , CCK (+), chromogranin (+), Synaptophysin (+), but immunoglobulin (-), LCA (-).

Thymic carcinoid prevention

1. Do not smoke or use nicotine products.

2. Regularly perform a cancer check and ask the doctor about the age and time interval requirements for physical testing.

3. Control drinking.

4. Protect the skin from the sun.

5. Actively participate in physical exercise.

6, according to height control weight in the normal range.

7, to avoid menopause hormone therapy.

8, think that the need for drug treatment, it is best to consult a physician first, this can reduce the risk of cancer.

9. Avoid exposure to carcinogens, radiation exposure and some chemicals can cause cancer.

10. Eat more foods and Chinese medicines to prevent cancer. Chinese medicine, such as ginsenoside Rh2 (protective), resists fatigue, increases human immunity, inhibits cancer cell proliferation, and has a very good effect on cancer prevention. The content is best at 16.2%.

Thymic carcinoid complications Complications Myasthenia gravis

Combined with extra-tumoral syndrome, the common extra-tumor syndrome has myasthenia gravis.

Thymic cancer symptoms Common symptoms Fatigue, night sweats, hemoptysis, upper limbs and facial blood vessels... Cushing's syndrome, lymphadenopathy, parathyroid function, hyperthyroidism

2/3~3/4 of thymic carcinoids are found in adult male patients, the ratio of male to female is about 3:1, the average age is between 42 and 50.6 years old, and 1/3 to 1/2 patients are asymptomatic before surgery. Unintentional findings in chest X-ray examination, and a few patients only have non-specific symptoms such as chest pain, cough, hemoptysis, and shortness of breath. If the tumor invades the superior vena cava, the superior vena cava syndrome may occur. Individuals may also experience fatigue. , fever, night sweats, etc., 30% to 40% of patients with thymic carcinoids often have typical Cushing syndrome (Cushing syndrome) before diagnosis, which is caused by atopic ACTH in neuroendocrine cells in thymic carcinoid tumors. Other endocrine disorders such as vasopressin syndrome, hyperparathyroidism, islet cell tumor, multiple endocrine neoplasia type I syndrome, horse syndrome and hypertrophic osteoarthritis are also not common, thymus Carcinoid patients are prone to distant metastasis, and 20% to 30% of patients have distant metastases of bone or skin at the time of presentation.

Examination of thymic carcinoid

1. Chest X-ray examination: manifested as a substantial block shadow of the anterior mediastinum, slightly lobulated, occasionally punctate calcification in the substantial block shadow, most of the asymptomatic thymoid cancer patients through the chest X Line inspection was found.

2. Chest CT scan: It is an important means to diagnose thymoid carcinoid, which can clearly show the shape of the tumor itself and the infiltration of adjacent organs, especially the enhanced CT can clearly show the condition of the superior vena cava invasion. The choice provides an important reference value. When the clinical appearance of ectopic ACTH syndrome appears, but the chest X-ray examination is not clear, the CT scan can often find smaller thymoid carcinoid lesions, making the diagnosis clear. Brown (1982) reported that 4 patients with clinically diagnosed ectopic ACTH syndrome and no chest X-ray findings were found to have anterior mediastinal tumors by CT and finally confirmed by surgery as thymic carcinoid, Jex (1985). In the Cushing's syndrome caused by ectopic adrenocorticotropic hormone-secreting tumors, 2 cases of thymic carcinoid tumors were found by chest CT scan and confirmed by surgery.

3. Bone radionuclide scanning: When the diagnosis is confirmed (surgical resection or biopsy), bone radionuclide scanning should be performed routinely, because about 1/3 of thymic carcinoid cases may have bone metastasis.

Diagnosis and diagnosis of thymic carcinoid

diagnosis

The diagnosis of thymic carcinoid is mainly based on clinical symptoms and CT examination. CT shows anterior mediastinal mass, mostly lobulated, intrauterine calcification, localized or invasive growth, often accompanied by mediastinal lymphadenopathy, the following conditions were found The possibility of this disease should be considered:

1 Clinically, there is Cushing syndrome, and the primary lesion of the adrenal gland is excluded. Chest CT examination should be performed, and sometimes small thymic tumors can be found.

2 SPECT or X-ray film suggesting bone metastases, should consider the possibility of anterior mediastinal mass as thymic carcinoid.

Differential diagnosis

Thymic carcinoids are also pathologically differentiated from other diseases.

1. Epithelial thymoma: The intranuclear chromatin of thymoma is not as homogeneous as thymic carcinoid, and is often divided into lobular shape by internal fibrous cords. The thymoid carcinoma is positive for immunohistochemical staining of chromogranin. And thymoma is negative.

2. Thymic parathyroid adenoma: This tumor patient often has hypercalcemia in clinical practice, which is opposite to the characteristics of endocrine pathological damage, but in some cases, there are no symptoms caused by hormones, so it is easy to be associated with thymic tumors. Confusion, under light microscopy, the following two differences are significant: most parathyroid adenomas do not have the characteristics of necrotizing vascular-like growth and daisy-like clusters in typical thymic carcinoid tumors, and PAS staining is strongly positive. Under electron microscopy, parathyroid adenomas have much less neurosecretory granules than thymic carcinoids. In immunohistochemistry, parathyroid hormone immunohistochemical staining of parathyroid adenoma is positive, while thymic carcinoid is negative. .

3. Mediastinal paraganglioma: similar in morphology to thymic carcinoid, but it does not necessarily appear in the thymus, but often occurs in large blood vessels; because it originates in the aorta, in the pulmonary artery or in the blood vessels The paraganglia, which is different from the larger duct-like growth of thymic carcinoid tumors, the tumor cells of the paraganglioma grow tightly clustered. In addition, the paraganglioma mitotic figures are rare, while the thymic carcinoid mitotic figures are more. See, argyrophilic staining is positive in paraneurma, while thymic carcinoid is negative, both methionine enkephalin and leucine enkephalin staining are positive, but more common in paraganglioma. .

4. Thymic metastasis: Some cases are very similar to thymic carcinoid, which is difficult to diagnose. On the contrary, thymoid carcinoma that grows in the form of a mesh is often a secondary tumor, not a primary lesion of the thymus, a carcinoid of the lung and intestine. Generally, there is little metastasis to the mediastinum and there is no obvious lesion in the primary tumor. However, we must perform fiberoptic bronchoscopy and phleboscopy before the diagnosis of thymic carcinoid tumor, whether it is primary or metastatic neuroendocrine tumor, NSE, Chromogranin and neuropeptide hormones are positive, so immunocytochemical staining has little effect.

5. There are a few cases of thymic carcinoids that must be differentiated from malignant lymphoma and mediastinal germ cell tumors. Immunohistochemical methods can be used to aid diagnosis. Lymphomas show white blood cell antigens, while germ cell tumors have placental alkaline phosphatase. However, thymic carcinoids do not contain these two substances.

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