Mediastinal lobar tumors and other tumors
Introduction
Introduction of mediastinal tumors and other tumors in the mediastinum Almost all mesenchymal tumors can be seen in the mediastinum. The mesenchymal tissues include fibers, fat, smooth muscle, skeletal muscle, mesothelium, synovium, blood vessels, histiocytes, and primitive mesenchymal cells (bone, cartilage, and lymphoid). Hematopoietic systems), which are a general term for a large group of organizations that have a common origin in embryology. basic knowledge The proportion of illness: 0.003% Susceptible people: no specific population Mode of infection: non-infectious complication:
Cause
Mediastinal tumors and other tumors in the mediastinum
The pathogenesis of mediastinal tumors in the mediastinum is similar to that of systemic soft tissue tumors. Although scholars at home and abroad have done a lot of work in genetics, environmental science, and immunovirology, the exact cause has not been confirmed.
1. The first thing that notices the wound is the relationship between some tumors and trauma on the body surface. There are also a few reports that the scar tissue of the operation, scald or chemical burn and the tissue near the foreign body are prone to soft tissue tumors, and the incubation period is 2 to 50 years.
2. Chemical Animal experiments have confirmed that subcutaneous injection of polycyclic hydrocarbons can produce a variety of sarcomas, but it has not been confirmed in human studies. Dibenzophenone in rust or defoliants can enter the body and accumulate in fat and In other tissues, it is not possible to metabolize rapidly, and it is possible to induce soft tissue sarcoma, but investigation reports from soldiers and local residents of the Vietnam War cannot confirm this.
3. Ionizing radiation radiotherapy patients with sarcoma in the radiation field, usually have an incubation period of 2 to 25 years, the most common type is malignant fibrous histiocytoma and angiosarcoma.
4. Benign tumor malignancy The vast majority of soft tissue sarcoma is primary, rather than benign from malignant tumors. The standard of judgment is generally that a benign tumor with a history of many years turns to grow rapidly, and it is found under light microscopy. Residual benign lesions can be considered as malignant, and some authors have repeatedly found that the tumor is malignant from the beginning in the observation of benign malignant cases.
5. Viral factors C-type virus, leukemia virus, Epstein-Barr virus were isolated in experimental animals and human soft tissue sarcomas, and patients with HIV infection were often associated with Kaposi's sarcoma.
6. Immune factors The occurrence of lymphangiosarcoma is always associated with chronic lymphedema after radical mastectomy. Long-term use of immunosuppressive agents such as cyclosporine can cause soft tissue sarcoma.
7. Genetic factors Soft tissue tumors known to be genetically related include leiomyoma, glomus tumor, xanthoma, and the like.
8. Gene mutations P53 mutations are not common in sporadic soft tissue tumors, but soft tissue tumors with abnormal expression of the P53 mutant Rb gene are known to be more aggressive than those without mutation.
Pathogenesis
The morphology of the mediastinal soft tissue benign tumor is similar to that of the original tissue. It is basically the same as the normal tissue, only the number or structure is slightly different. The morphology of the mediastinal malignant soft tissue is different from the normal tissue, and the degree of cell differentiation is different. The high, often can find some morphological characteristics similar to the origin of the tissue in the tumor, and sometimes difficult to identify, must be identified by immunohistochemistry, electron microscopy and other methods combined with clinical.
Prevention
Mediastinal tumors and other tumor prevention
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.
Complication
Mediastinal tumors and other tumor complications Complication
Generally no complications.
Symptom
Mediastinal leaf-borne tumors and other tumor symptoms Common symptoms: night sweats, poor chest pain, difficulty swallowing, difficulty breathing, shortness of breath, chest tightness, pleural effusion, weight loss
Mediastinal tumors in the mediastinum can be present for many years without symptoms. More than half of them are due to accidental findings. They can also be in physical examination or in autopsy reports. The most common complaints are chest pain, cough, shortness of breath, difficulty swallowing, and hoarseness. , Horner syndrome, superior vena cava compression and trachea, heart compression, etc., as well as some non-specific symptoms, such as fever, night sweats, general malaise, anorexia, weight loss, etc., these same tumor location, size, nature and The growth mode is related, the benign tumors are less likely to have symptoms, the cystic nature produces less symptoms than the solid tumors, the swelling growth will produce compression symptoms, and the invasive growth often has the corresponding symptoms of the affected organs. The clinically common mesenchymal tumors have :
1. Mediastinal fat-derived tumors are divided into benign and malignant tumors, benign tumors account for the majority, of which less common in the mediastinum, can occur in any part of the mediastinum, most of the anterior mediastinum, paraventricular or palpitations, incidence The reason is unknown. Some people think that it originates from the subperiosteal or subcutaneous adipose tissue of the chest wall, and it is also believed to originate from the degenerated thymus tissue.
(1) mediastinal lipoma: one of the more common mesenchymal tumors in the mediastinum, can occur at any age, a little more adult males, the tumor usually envelopes intact, mostly spherical, nodular or irregular, The cut surface is light yellow or yellow, greasy, often divided into small leaf-like structures of different sizes. The texture is soft and the volume is usually large, which may be accompanied by hemorrhage, necrosis, liquefaction, cystic change and ossification. Learning mainly consists of mature adipose tissue, often extending into the neck, intercostal or spinal canal, slow growth, occasional malignant transformation, clinically no obvious symptoms, such as large tumor volume can oppress the surrounding tissue, can produce corresponding symptoms, CT It is of great value in the diagnosis of fatty tumors. It has a good contrast in the mediastinum. A circular mass of the posterior mediastinum of the sternum can be seen. The CT value is low, which can be -100HU. The tumor edge is clear and free from invasion. Diagnosis of mediastinal lipoma should be Pay attention to the search for thymus tissue components in mediastinal lipoma to rule out the diagnosis of thymoma. It should also be differentiated from hyperlipidemia. Because the tumor has a complete capsule, surgical resection is not difficult, and the general prognosis is good. .
(2) mediastinal liposarcoma: its etiology is unknown, occurs in the mediastinum, rare men are slightly more than women, more common in 40 to 60 years old, rare in adolescents, the vast majority of primary tumors, but also from benign lipoma malignant It is reported that liposarcoma is usually large in size, nodular or lobulated, and can have a thin fibrous envelope. The well-differentiated face resembles a lipoma. If accompanied by fibrous tissue hyperplasia, white cords can be seen interspersed with mucus. Type of lipoma is jelly-like, round cell type and pleomorphism is fish-like or brain-like, may have hemorrhagic necrosis, microscopic tissue morphology, currently divided into well-differentiated, mucinous, round cell type And phlegm and dedifferentiation type 5, plus 5 kinds of tumor components at the same time mixed type, fat sarcoma mostly located in the posterior mediastinum, the course of disease is longer, the preoperative course varies from several weeks to several years, often with obvious chest pain, Large tumors can produce compression symptoms, CT is important for diagnosis. MRI can be multi-dimensionally scanned compared with CT. It is superior to CT in the scope of tumor expansion. Local extensive resection, including sarcoma capsule, radiotherapy It has an effect on mucinous liposarcoma, and the more mucus, the better the effect. The prognosis of liposarcoma in the mediastinum is worse than that of the superficial one. The prognosis of intracapsular resection is poor during surgery, and the 5-year survival rate of liposarcoma is 40% to 64%. The recurrence rate is high, and it has been reported to reach 24%. Patients with recurrence should strive for reoperation.
2. Mediastinal fibrous tissue-derived tumors Fibrous tissue tumors are composed of fibroblasts, fibroblasts and collagen fibers. They are classified into benign and malignant according to the degree of differentiation and maturity. The mediastinal fibrogenic tumors are very rare. In 1990, 1796 cases of mediastinal tumors were treated, of which only 17 cases were fibrogenic tumors. Other cases were only reported in scattered cases. At present, it is customary to classify such tumors as fibromatosis, fibrosarcoma and malignant fibrous histiocytoma.
(1) mediastinal fibromatosis: is a fibrous tissue proliferative disease, composed of collagen fibers and mature fiber cells, the cause is unknown, may be related to some inflammation or tumor-producing active substances, may also be an allergic reaction and itself Immune disease, biological behavior between benign and malignant, there is no obvious margin in the general morphology, diffuse nodular hyperplasia and nodular hyperplasia, most of the patients are middle-aged, the clinical symptoms are mainly due to the chest mediastinum Organs are caused by proliferative fibrous tissue wrapping and compression. They can surround the aortic arch, trachea, bronchus, heart, etc., and are often noticed because of obstruction of the superior vena cava. Others have chest pain, fever, difficulty swallowing, hoarseness, and accelerated blood sedimentation. If the tumor does not metastasize, the treatment should be completely resected, and the resection will not completely recur.
(2) mediastinal fibrosarcoma: the cause is unknown, in the mediastinum is rare, mostly located in the posterior mediastinum, the tumor is mostly round or elliptical, large volume, generally has a false envelope, the well-differentiated face is grayish white, tough texture, there are Vortex-like structure, poorly differentiated cut surface, such as fish-like, soft texture, visible hemorrhagic necrosis, microscopic composition of spindle-shaped fibroblasts, and contains reticular fibers and collagen fibers, some areas show mucinous changes, visible mitotic figures The cells exhibit different degrees of heteromorphism. According to the number of cells, the degree of differentiation, the number of collagen fibers and the number of mitotic figures, they can be roughly divided into three levels: those with better differentiation are at the first level, and those with poorer are at the second level. Grade, the worst is grade III, which has a guiding effect on prognosis. The tumor grows rapidly, the local infiltration spreads, and there is little distant metastasis. It is usually found when it is found. It usually produces symptoms, complaining of cough, chest pain, difficulty breathing and swallowing. Difficulties, etc., some large tumors will secrete insulin-like factors, causing hypoglycemia, chest X-ray findings of fibrosarcoma and fibroids are not characteristic, no good hair , usually clear outline, protruding to the mediastinum side, no calcification, can be complicated by pleural effusion, due to severe external invasion of the mass, the boundary is unclear, complete resection is more difficult, according to the lesion site design appropriate surgical incision, the operation is smooth It is very important that the surgical treatment of such tumors is still the main treatment method. The effect of radiotherapy or chemotherapy is uncertain, and the patient's prognosis is poor. Most patients die of intrathoracic spread within a few years after the tumor is discovered.
(3) mediastinal malignant fibrous histiocytoma: malignant fibrous histiocytoma is the most common soft tissue sarcoma in the elderly, only a very small number of lesions are primary in the mediastinum, there is no difference between men and women, the posterior mediastinum is more common, followed by the mediastinum, Usually malignant fibrous histiocytoma is invasive growth, no capsule, but there are some people in the country that the malignant fibrous histiocytoma in the mediastinum has more capsules, and the tumor can grow larger, usually in nodular shape. The cut surface is grayish white fish-like, or yellow or yellowish brown. Large tumors are often accompanied by hemorrhagic necrosis and cystic changes. For example, there are many fiber components, the texture is hard, and when there are more mucus components, it is translucent mucus-like. The morphology of the lower tissue can be seen as its main components are fibroblasts and histiocytes, and can also be associated with a number of mononuclear and multinucleated giant cells, foam cells and undifferentiated primitive mesenchymal cells and various inflammatory cells. Different types of transitional cells, fibroblasts are slender or obese fusiform, arranged in a special mat-like structure, and the tissue cells are generally round or polygonal. Rich, the number of mitotic figures in the tumor varies, and the mitotic figures are more common. The early stage is often asymptomatic and difficult to find. Only when the tumor grows to compress the surrounding organs or large blood vessels, the symptoms appear. The chest X-ray can indicate the mass. Exist, more common in the posterior mediastinum, often expressed as a round or irregular mass, protruding to the mediastinum side, the size is not equal, the density is generally uniform, a few density is uneven, may be accompanied by calcification, CT can clearly understand the mass The relationship with the surrounding tissues, especially the blood vessels, is helpful for the development of surgical procedures. When the lesions are small, the edges are smooth, the density is uniform, and the larger ones are irregular, often accompanied by necrosis (55%) and calcification (7% to 20%). Invasion of adjacent organs and tissues, diagnosis usually requires the use of pathological biopsy, surgical treatment is preferred, surgical procedures are as complete as possible, and the effects of adjuvant therapy such as radiotherapy and chemotherapy before or after surgery have not been confirmed. Malignant fibrous histiocytoma is highly malignant. The local recurrence rate is 40% to 55%, the metastasis rate is 14% to 55%, and the most common is lung metastasis. The 5-year survival rate is 36%.
3. Solitary fibrous tumors occur very rarely in the mediastinum, and nearly half are malignant. The tumor originates from the sub-differentiated undifferentiated mesenchymal cells. The incidence is not related to the history of asbestos exposure. The tumor is isolated, limited, and generally has fine pedicles. Guangji, often with a complete capsule, and a pleura attached to the surface, the ultrastructure suggests that the tumor cells are fibroblasts in nature, immunohistochemically visible vimentin positive, sometimes keratin negative, more common in adult males, often chest pain, Cough, difficulty breathing and fever, etc., may have osteoarthritis, clubbing and hypoglycemia, there may be metastasis, more common is the liver, but also lymphatic metastasis, treatment with surgical resection, postoperative supplement with radiotherapy And chemotherapy, benign general prognosis is good, rarely recurrence, long-term survival rate of malignant patients is very low, easy to relapse, most recurrence cases survive less than 5 years.
4. Mediastinal angiogenic tumor angiogenic tumors are rare in the mediastinum. Case statistics suggest that the incidence rate is 0.5% to 1.5% of mediastinal tumors, and 10% to 30% of them are malignant. The etiology and pathogenesis are unknown and can occur in the mediastinum. Any part of the previous upper mediastinum.
(1) mediastinal hemangioma: cavernous hemangioma is more common, some are capillary hemangioma, which account for 90% of benign hemangioma, venous type has also been reported, mostly in the visceral area or paravertebral groove, occasionally can be extended to the chest wall In the neck and spinal canal, the tumor may have a thin layer of capsule, mostly purplish red, soft and indefinite, and a few have hemorrhagic manifestations. The tumor under the microscope consists of an expanded lumen lined with a thin layer of endothelium. Separated by slender fibrous tissue, visible foci thrombosis, calcification, cholesterol granuloma, more common in young adults, gender differences, the patient is asymptomatic, the occurrence of symptoms and tumor size and the surrounding tissue compression or invasion, Can have chest pain, chest tightness, cough and other symptoms, CT can help diagnose the hemangioma, visible mediastinal soft tissue masses, medium density, size, border clear, but also blurred, easier to show veins than X-ray The existence of stone, surgical treatment is the first choice for surgical resection.
(2) vascular endothelial cell tumor: histological performance is between benign and malignant, originated from vascular endothelial cells, can be invasive growth, and may have regional lymph node metastasis and important organ metastasis, of which lung and liver are common metastases The site is a low-grade malignant tumor. The microscopic shape is small, the mitotic image is rare, the operation should be extensively removed, and there is a certain recurrence rate.
(3) vascular endothelial sarcoma: occurs in the mediastinum is very rare, the cause is unknown, the tumor is generally no capsule, extensive hemorrhage and necrosis, dense tumor cells, abnormal shape, mitotic figures are easy to see, cells are generally surrounded by reticular fibers Intrathecal, solid sheet, no obvious cavity, high degree of malignancy, rapid disease progression, invasive growth, lymphatic and lung metastasis, sometimes found in surgery can not be removed, patients relapse in the short term after surgery, survival The period is shorter.
(4) vascular smooth muscle tumor: mainly located in the distal subcutaneous tissue of the extremities, rare in the mediastinum, can occur at any age, any part of the mediastinum, of which the anterior mediastinum is more common, pathologically except for the performance of smooth muscle tumors, but also its own Features: The tumor boundary is clear. The smooth muscle bundle is arranged concentrically around the thick-walled blood vessels. The peripheral cells gradually merge with the extra-wall smooth muscle cells. There is no abnormality, no mitotic figures, thick blood vessels, and narrow cysts. The wall has no elastic plate and outer membrane. The tumor has huge compression symptoms. The preoperative diagnosis depends on the biopsy. The surgery is preferred and the prognosis is good.
(5) vascular leiomyosarcoma: the inferior vena cava of the disease site, common pulmonary artery, the primary blood vessel is not easy to be found when the lesion is located in a small blood vessel. The diagnosis is controversial. It must be combined with the size of the tumor, the location of the disease, the presence or absence of metastasis and the number of mitosis seen under the microscope. It is determined that surgical treatment is preferred. The scope of surgery includes the entire tumor and its adjacent blood vessels and adhesion tissues. It has been reported that the recurrence rate is 75%. Some people have given radiotherapy to relapsed patients, but it has not been successful. Chemotherapy is only beneficial for a few cases.
(6) Vascular epithelial cell tumors: originated from the vascular epithelial cells may have benign and malignant points, but pathologically difficult to distinguish, tumors can occur in any part of the body, the lower extremities, retroperitoneum and head and neck are the most common, occurring in the mediastinum rare, There are no differences in age and gender, and the length of the disease varies. From several years to several decades, the growth is slow. The dissemination of blood is the main way of metastasis. It is common in the lungs and bones. Most patients are asymptomatic. Later, due to the huge mass or infiltration of the mass. Symptoms of compression, among which the more specific symptoms are hypoglycemia, the cause may be related to the secretion of renin from the tumor, the use of glucose in the blood is consumed and consumed. Once the tumor is removed, the blood sugar can return to normal, and the diagnosis depends on pathological determination, MRI and Angiography can show the tumor-rich vascular network and clear the boundary. It also shows the branches of the tumor-fed arteries and their radiation. Preoperative embolization can reduce the blood supply of the tumor. Because the tumor is clear or has a thin layer of membrane, it is easy to be surgically removed. There may be recurrence after surgery, radiotherapy can be used as an adjuvant therapy, and chemotherapy has little effect.
Mediastinal lymphangiogenic tumor
(1) mediastinal lymphangioma: lymphangioma is a deformity rather than a true tumor, causing traffic failure of the lymphatic system and the venous system, belonging to congenital diseases, may also be secondary to surgery, after trauma, accounting for 0.7% of mediastinal tumors ~ 4.5%, the most common in the neck, less common in the mediastinum, and mostly the extension of the neck to the mediastinum. Clinically, the lymphangioma is divided into a neck type, a cervical mediastinum type, a mediastinal type, according to the abnormal lymphatic vessel size. , divided into 3 types,
1 capillary type: composed of small lymphatic vessels;
2 Sponge-like type: consists of lymphatic vessels that are dilated in the lumen. The lumen contains lymph fluid, interstitial connective tissue is often increased, and there are scattered lymphocytes and lymphoid follicles, which often grow along the interstitial space and are not easily removed.
3 cystic lymphangioma: this type is most common.
(2) lymphangioma: all occur in women's benign tumors, originally called lymphatic epithelioma, whose localized lesions can be located in the mediastinum, often in close relationship with the thoracic duct and its branches, leading to chylothorax, Diffuse type is called lymphangiomyomatosis, which can affect the lungs. Some cases occur in the background of nodular sclerosis syndrome, suggesting that its pathogenesis is related to the female hormone. Some people think that it is a kind of The hamartoma has a good surgical effect.
6. Mediastinal myogenic tumor
(1) mediastinal rhabdomyomas: this tumor can occur in any part, even in the absence of skeletal muscle, rarely seen in the mediastinum, Miller (1978) once reported 1 case of this tumor in the anterior mediastinum, and speculated It originated from thymocytes, and there are few reports in domestic journals. The tumor has a good prognosis.
(2) mediastinal rhabdomyosarcoma: rhabdomyosarcoma is a malignant tumor composed of skeletal muscle cells with different degrees of differentiation. The cell morphology is diverse. It is clinically divided into embryonic types according to the degree of tumor cell differentiation, special tissue structure and giant morphology. (including grape family), spindle cell type, acinar type and polymorphic type 4, of which embryo type is the most common, can occur at any age, different pathological types have different ages of onset, acinar type occurs mostly in Adolescents, embryos mostly occur in babies, pleomorphism mostly occurs in the elderly, males are more common than females, mediastinal rhabdomyosarcoma is often asymptomatic, and even due to the first symptoms of the metastatic site, the primary lesion is found, the mass is larger Symptoms of peripheral organ compression may occur. Because of the high degree of malignancy, rapid growth, early detection is not easy, and lymphatic or hematogenous metastasis is found when there is no significant organ metastasis. The mass should be completely restricted to the mediastinum. Resection, combined with radiotherapy and chemotherapy, the pathological classification of rhabdomyosarcoma can determine the prognosis, especially in children and blue Juvenile, the best type of prognosis is grape rhabdomyosarcoma, the 5-year survival rate is 95%; followed by spindle cell type rhabdomyosarcoma, 88%; embryo type 66%; acinar type and polymorphism, It is 54% to 62%.
7. Other rare mesenchymal tumors occur in other medial lobe tumors of the mediastinum, as well as mesenchymal tumors, meningioma, synovial sarcoma, extraosseous osteosarcoma, chondrosarcoma, etc. and inflammatory masses of yellow granules. Swelling, the latter is a mass formed in the mediastinum of non-tuberculous granulomatous lesions in the lymph nodes. The chest X-ray shows a round or lobulated block that protrudes into the lungs with a smooth edge and a large mass that can produce compression symptoms. Surgical treatment.
Examine
Examination of mediastinal tumors and other tumors in the mediastinum
The diagnostic value of X-ray chest radiograph is limited, but it can provide the location, size, anatomical structure of the lesion in the mediastinum, and whether the relative density of the mass is cystic or solid, with or without calcification, is the basic examination method for diagnosis; The diagnostic value of CT is high, especially in the mediastinum, which can show the morphological features of mediastinal anatomy and space-occupying lesions. The enhanced scan can distinguish the relationship between the mass and the blood vessel; MRI has good The soft tissue resolution and contrast resolution clearly show the mediastinal anatomy under the background of the empty blood vessels, and no radiation, no need for angiography, very clear, superior to vascular malformation or vascular-related diseases; Preoperative cell diagnosis, but less tissue, often difficult to diagnose.
Diagnosis
Diagnosis and differentiation of mediastinal tumors and other tumors in the mediastinum
Because the source of mesenchymal tumors occurring in the mediastinum is different, the symptoms are few, no specificity, preoperative diagnosis depends on pathological support, of course, combined with clinical history and physical examination, the selection of appropriate auxiliary examination means is conducive to improve preoperative Diagnostic accuracy.
The staging and grading of soft tissue sarcoma is very important for the diagnosis, treatment, prognosis evaluation and research. Due to the small lymphatic metastasis of sarcoma, the classic TNM staging is difficult to describe accurately, and the classification is too complicated and difficult to master. Many clinicians like to be simple. And the classification system that is helpful for clinical diagnosis and treatment, such as the possibility of metastasis <15%, is classified as low-grade malignant, on the contrary, highly malignant, this secondary system makes them easier to make treatment choices, but this method Too simple to comprehensively reflect changes in the extent of sarcoma morphology and biological behavior.
According to the cell structure, morphology, mitotic image and the degree of necrosis of cells, the grading standard is determined, wherein the grade G1 shows low degree and G2 shows height; the anatomical part T1 is intra-region and T2 is outside the region.
Generally not confused with other diseases.
