Tumors of mediastinal paraganglionic origin

Introduction to tumors originating from the mediastinal paraganglia Tumors originating from the paraganglia belong to the APUD system tumors and are classified into two types: biologically active tumors and biologically inactive tumors. Non-biologically active tumors are non-chromophobic paragangliomas (also known as chemosensory tumors), and bioactive pheochromocytoma, both of which can be malignant. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious complication:

Tumor cause of mediastinal accessory ganglion origin

(1) Causes of the disease

The paraganglial origin of the tumor originates from the parasympathetic ganglia referred to as the "secondary section". The secondary section is relative to the ganglion in the sympathetic trunk. It is mostly located on the side of the sympathetic trunk, and occasionally in the distant parts such as the internal organs. According to the reaction of its main cells to chromium salts, there is a difference between chromophore and non-chromate. Therefore, paraganglioma also has chromophore and non-chromate. The pheochromic paraganglioma is adrenal gland. Quality is the main representative, the tumors that occur from it, commonly known as "pheochromocytoma" (Pheochromocytom instead of chromophobic ganglion tumors are often referred to as "paraganglioma", also referred to in the literature as "non-chromophobe Nonchromaffin paraganglioma and chemical receptor tumors (Chemodectoma).

Mediastinal pheochromic paraganglioma is rare, less than 1% in all mediastinal tumors, less than 2% in all pheochromocytoma, although most occur in the anterior mediastinum, originating from the aorta or the main, pulmonary artery Paraganglia, island-like tissue on the atria and pericardium, cardiac paraganglioma often occur in the left atrium, left ventricle, left atrioventricular sulcus, can also occur in the right atrium, right ventricle, and others from the aorta Sympathetic, paraganglia, mostly located in the posterior mediastinum along the rib cage, the tumor volume is different, the diameter is from 1 ~ 2cm up to 25cm, most of them are benign, only about 10% is malignant, surgical resection specimens are usually 5 ~ 6cm, only About 14% of the clinical can be affected, the size of the tumor is not necessarily proportional to the severity of the symptoms, sometimes the smaller the volume has obvious symptoms, while the larger ones remain "physiologically quiet", but the accidental discovery at the time of autopsy, most of the tumors It is spherical, oval or slightly lobulated, and the capsule is not obvious in small volume. For larger ones, the tumor is mostly solid, and the fresh specimen is gray-red, common bleeding, necrosis and cystic. Variable stove In the formalin solution (or exposed to air) gradually converted to brown, in the case of chromium salt solution, the color immediately becomes deeper, and the oxidation process of catecholamines is greatly accelerated in sunlight.

Pheochromocytoma can be accompanied by other APUD tumors at the same time or in succession, such as thyroid malignant C cell tumor ("medullary carcinoma"), pituitary adenoma, parathyroid adenoma, islet cell tumor, carcinoid and neurofibromatosis, etc. It becomes one of the components of endocrine gland adenoma.

Non-chromophobic paraganglioma ("paratypic tumor", "allelopathy") This tumor is relatively rare, Zhang Xun et al (1994) reported that 0.52% to 4.3% of mediastinal tumors in the same period; Zhang Helin (1995) reported Accounted for 10.74%, which may be related to the scope of hospital admission, can be seen in the mediastinum and posterior mediastinum of the paraspinal sulcus, the latter is more common, mostly benign, only about 10% is malignant, and the paraganglioma is mostly "non-functional" "Of, but occasionally there may be functional activity. The neurosecretory products are mainly norepinephrine, and there may be traces of adrenaline. Clinical symptoms of pheochromocytoma may occur. Massage of tumors may increase blood pressure, non-functional side. Electron microscopy of ganglion, cytochemical method can show neurosecretory granules, biochemical determination can accurately quantify the content of norepinephrine and adrenaline (up to 24.5g / g tumor tissue), when the content reaches 1.5mg / g can appear typical Symptoms of pheochromocytoma.

The majority of pheochromocytoma is a benign category in terms of growth characteristics. However, because tumor cells often secrete a large amount of catecholamines, patients can die of hypertension and its complications, but they cannot be called fatal. Malignant, the benign and malignant problems of pheochromocytoma, like other endocrine gland tumors, cannot be identified by the morphology of tumor cells alone. One type is that the tumor cells have obvious atypia, fusiform, singular, and deeply stained. Or large multinuclear tumor cells with more mitotic figures, but the biological behavior is neither infiltration nor metastasis. On the contrary, occasionally morphologically well differentiated, but unexpectedly metastasized, or localized infiltration of tumor cells (invasion of the capsule or blood vessel), but no metastasis, metastasis occurs in the lungs, bones, lymph nodes, brain, etc., metastases can sometimes be manifested after years of resection of the primary tumor, and occasionally the original foci are concealed, and Cases in which the metastases first develop symptoms (such as intracranial metastases).

(two) pathogenesis

Pathological manifestations:

1. Chromosome paraganglioma cells are largely similar to the tissue of their origin, small in size, non-enveloped, well-differentiated pheochromocytoma sometimes difficult to distinguish from medullary hyperplasia, tumor cells usually have irregular polygons The volume is slightly larger than normal, the cytoplasm is rich, granular, sometimes empty, the boundary is not very clear, the nucleus is round or oval, often biased, the nucleus can be loose, but the deep dye is not uncommon, sometimes It can be seen that the nucleolus is coarser, the tumor cells and the nucleus can have a certain degree of abnormality, and the mitosis is occasionally seen. The tumor cells can be dispersed, and can be pseudo-aciniferous, bundle-shaped, trabecular or small-like, with only a small amount of slenderness. Connective tissue interstitial, rich in blood vessels, often dilated into sinusoids, tumor cells are often accompanied by some small round cells, some may be naive chromoblasts or even sympathetic cells, and some are lymphocytes Sometimes, tumor cells can be further differentiated into more mature ganglion cells, which are small colonies, which may be associated with neuronal fibers and nerve sheath cell proliferation (Fig. 1). Occasionally, a part of the tumor appears as a ganglion cell neuroma, a ganglion neuroblastoma or a neuroblastoma, and may also be accompanied by an adrenal adenoma.

2. Non-chromophobic paraganglioma showed ovoid, slightly lobulated, elastic lumps, smooth surface, often closely attached to the large vessel wall, and the capsule is often incomplete, especially in the carotid artery. Parallel nodules, the latter often have local infiltration, the face is grayish red to brownish red, the blood vessels are very rich, sometimes resembling hemangioma, the image of endocrine gland tumors can be seen under light microscope, composed of epithelial-like main cells arranged in a nest It is separated by a fibrous vascular stromal that is enriched and expanded into a sinusoidal sinus. The peripheral part of the nest may have supporting cells (Fig. 2), and nerve fibers are often difficult to detect.

The main cells are bright and dark. Each of the bright cells is large, polygonal, cytoplasm rich, transparent, containing chromophilic fine particles. The silver impregnation method can show the chrome-like particles of the tip size and the blood vessels of the main cell nest. The basement membrane grid, the cell nucleus is small round or oval, the nucleus is empty and bright, the nucleolus is clear, the dark cell is small, the cytoplasm is dark, the nucleus is deeply stained, the nucleolus is not obvious, and the mitosis is rare.

Under electron microscope, bright cells contain more neurosecretory granules, and the boundary membrane is obvious. There is a core with high electron density. Dark cells only contain a small amount of particles in some cells. The latter is bulky and not regular, and the paraganglioma of different parts. It is indistinguishable from the ultrastructure.

Malignant people, like many endocrine gland tumors, are difficult to identify from the morphological features of the tumor. The abnormality of the tumor cells is not necessarily a sign of malignancy. The center of the tumor cells is found to have more necrotic and mitotic images, infiltrating blood vessels and capsules. Both help to speculate that it may be malignant.

Tumor prevention of the mediastinal paraganglia origin

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Tumor complications of the mediastinal paraganglia origin Complication

Generally no complications.

Symptoms of the origin of the mediastinal paraganglia Common symptoms Anxiety, nausea, shortness, tension, weight loss, pale, dizziness, low blood pressure

1. Non-chromophobic paraganglioma is mostly benign, usually asymptomatic. Most of the physical examination reveals mediastinal shadows. The symptoms are mainly caused by tumor compression around the organs.

2. Chromotropia paraganglioma is more common in young adults. The main symptoms are hypertension and metabolic changes, which are easy to attract attention. Hypertension may have both paroxysmal (bursty) and persistent types. There is no difference in general hypertension. Patients may have heart palpitations, shortness of breath, chest depression, dizziness, headache, sweating, sometimes nausea, vomiting, abdominal pain, blurred vision. Some patients have mental stress, anxiety and fear, pale, Cold limbs, tremors and other symptoms, sometimes blood pressure can rise 195mmHg (26.0kPa) or more, the attack usually lasts for several minutes to several hours, often accompanied by orthostatic hypotension, persistent hypertension can eventually lead to malignant hypertension, only Symptoms can be relieved after tumor resection. Due to increased basal metabolism and impaired glucose tolerance, patients may have fever, weight loss, weight loss and hyperthyroidism. In children with abdominal pain, constipation, sweating, blurred vision is also prominent. The patient is usually asymptomatic.

Examination of tumors originating from the mediastinal paraganglia

Measuring the elevation of urinary catecholamines and their metabolites high vanillic acid (HVA) and vanillyl mandelic acid (VMA) often leads to a diagnosis.

1. Chest X-ray shows similar X-ray signs as other neurogenic tumors. The posterior mediastinal paravertebral sulcus has shadows of different sizes. It also shows that the mass is above the ascending aorta, overlapping with the spine, and the density is uniform. Clear borders. When tumors and aortic aneurysms and brachiocephalic aneurysms are indistinguishable, selective angiography can be used to clearly show the source of blood vessels. In 30% of cases, tumor burrs can be seen in chest angiography. The diagnosis and location of the pre-tumor is helpful.

2. CT scan showed that the anterior mediastinal aortic arch or posterior mediastinal mass was mostly substantial, with uniform density of shadows, and sometimes visible cord-like shadows were connected to the aorta. Because of the abundant blood vessels of this tumor, CT enhanced tumors can be obvious. Strengthen the development.

3. Methyliodophenyl hydrazone [131I-MIBG] scintigraphy has a significant effect on tumor localization, with a sensitivity of 85% with MIBG scanning.

4. MRI has a certain value in the diagnosis of paravertebral masses as paraganglioma. Paraganglioma shows a non-homogeneous mass with a flowable substance inside. The latter characteristic is due to the rich blood vessels and blood flow velocity. fast.

Diagnosis and diagnosis of tumors of the mediastinal paraganglia origin

According to the history and clinical manifestations, combined with routine laboratory tests and X-ray, CT and other examinations can be diagnosed, the final diagnosis still requires pathological examination.

Generally not confused with other diseases.

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