Synovial sarcoma

Introduction to synovial sarcoma Synovial sarcoma (synoviosarcoma) is a highly malignant soft tissue sarcoma that originates from mesenchymal cells with synovial differentiation but is rare in the joint. Synovial sarcoma is the fourth most common soft tissue sarcoma, occurring between the ages of 15 and 40. It rarely occurs from the synovial membrane of the joint, but occurs from the soft tissue near the joint, sometimes even away from the joint. Occurs in the limbs, about 70% occur in the lower extremities, especially in the vicinity of the knee joint, followed by the foot and ankle, the upper limbs are more elbows, and other parts not related to the joint such as the head and neck, abdominal wall, posterior peritoneum can also occur . basic knowledge The proportion of illness: 0.006% Susceptible population: good for adolescents and middle-aged male patients Mode of infection: non-infectious Complications: lung metastases

Synovial sarcoma

Genetic (30%):

There is a similarity between traits between parents and children, indicating that traits can be passed from parents to offspring. This phenomenon is called heredity. However, in genetics, it refers to the phenomenon that genetic material is passed from generation to generation. It is known that the existing life on earth is mainly DNA as genetic material. Genetics is one of the most important factors for prenatal and postnatal care. In addition to heredity, the factors that determine biological characteristics are the environment, and the interaction between environment and heredity.

Trauma (30%):

External damage caused by the impact of an external object, collision, or chemical attack on the body or object, which may cause synovial sarcoma.

Disease factors (25%):

Such as extra-osseous chondrosarcoma, knee joint tuberculosis, synovitis and other diseases are synovial sarcoma.

Pathogenesis

The pathogenesis of synovial sarcoma is still unclear.

Generally seen

In the hand, the small stage I lesion, the capsule is intact and easy to separate. Although the tumor starts from the synovial membrane, it is not like the ganglion cyst. It does not communicate with the joint cavity or tendon sheath. The tumor section is soft and fleshy. , no cysts, can secrete mucus, deep synovial sarcoma in the large limbs, high malignant grade, its capsule is incomplete, surrounded by edema, vascular rich inflammatory reaction tissue surrounded, blunt outside the mass Sexual exfoliation, often tearing the envelope, the tumor is soft, white meat-like substance, secreting gelatinous liquid, its softness can be sucked out by the suction device.

2. Histological form

Histologically, it is generally divided into two-phase type and single-phase type. The biphasic type generally has the same number of epithelioid-like cells and spindle-type cells, and is evenly distributed. Some epithelioid cell cords can form a vessel-like atypical pseudogland. Cavity or small sinusoidal fissures, monophasic epithelial cells, or spindle cells, in some cases, in biphasic cells, the tumor tissue is seen from undifferentiated small circles It is composed of a shape or an oval tumor cell. This type is also called an undifferentiated type and has a high degree of malignancy.

The tissue of the small synovial sarcoma of the hand and the foot is biphasic, and part of it is a group of synovial cells in the lightly stained mucus. The cells are often glandular, showing no cell fissures, like being slit. Open capillaries, but it is not endothelial cells but tumor cells. The protein saccharides contained in this tissue can be confirmed by histochemical methods on frozen sections. Another area of this tumor is composed of fibroblasts. It is a spindle-shaped cell, occasionally a split-like image, arranged in a fibroid-like herringbone shape. The cells are in the same proportion as the matrix. There are clear fibers in the eosinophilic matrix, and the synovial cells can be produced like other cells. collagen.

Synovial sarcoma prevention

Synovial sarcoma is more common in adults, and occurs in all major joints of the extremities. It is a malignant tumor. If it occurs in a mass around the joint, the possibility of synovial sarcoma should be considered. CT and isotope scans should be performed to determine the extent and systemic status. The diagnosis is based on the biopsy pathology report. Treatment depends on the location and extent of the tumor to determine limb salvage or amputation surgery or radiotherapy or chemotherapy.

Since the cause of this disease is unknown, there are no effective preventive measures. Early detection and early diagnosis and early treatment are the key.

Synovial sarcoma complications Complications

The disease can be transferred to the lungs (the lesion usually manifests as stage IIB sarcoma), but lymphatic metastasis is not uncommon.

Synovial sarcoma symptoms Common symptoms Synovial black stained knee joint swelling... Knee joint swelling, blood stasis, knee joint swelling, knee joint effusion, knee joint effusion

Most of them are large, fast-growing tumors that grow on the thighs, buttocks, shoulder blades or upper arms. The small ones are full length on the back of the hand, superficial masses on the back of the foot, mild pain and tenderness, sometimes no obvious symptoms, and slow growth. The swelling is more diffuse, the local skin is red, the skin temperature rises and the venous engorgement, the movement is limited, and some grow rapidly at the beginning, the performance is significant, the early metastasis, the synovial sarcoma than other soft tissue sarcoma lymph node metastasis There are many opportunities.

Clinical manifestation

More common in adolescents and middle-aged patients, males are more than females. The most common sites are near the large joints, mainly in the knees. Secondly, in the vicinity of the ankles, hips and shoulder joints, more than half of the diseases occur in the lower limbs, one quarter. The case occurred in the upper limbs, less neck and trunk, tumor invasive growth, easy recurrence after resection, different course of disease, initially a painless mass, growing up and varying degrees of pain, general tumors can invade surrounding bone tissue, tumor When the block is large, the joint activity is affected. The synovial sarcoma shows mild symptoms. The soft tissue mass located in the deep deep fascia is slowly increasing painlessness. The adjacent joint mass is the main clinical manifestation. The physical examination shows that the mass of the mass is hard and deep. The structure is fixed, it is the most common soft tissue sarcoma near the hands and feet, and the synovial sarcoma in this area is often mistaken for ganglion cyst.

2. Natural course

The primary mass grows slowly, initially pushing adjacent soft tissue and bone, and then invading it. Compared with the lesions that occur in the back of the hand and foot, the masses that occur in the muscle-rich parts of the limb usually grow more rapidly, and the incidence of local lymph node involvement is significantly higher. In other soft tissue sarcomas, the distant part of the metastasis mainly to the lungs (the lesion usually manifests as stage IIB sarcoma), and the lesions of the hands and feet progress slowly and are painless compared with the lesions occurring in the proximal and trunk parts of the limb.

3. The location of the disease

The disease occurs in the para-articular tissues of the limbs and in the periorbital tissues of the hands and feet. It occurs around the calf and knee joints. The tumor can invade the tendon sheath and bursa of the tendon, often adjacent to the joint, but rare in the joint. Lesions located in the upper extremities are more common in the volar side, and synovial cell sarcomas are also common in the feet.

According to the clinical manifestations, combined with imaging examination, the disease should be thought of, and the diagnosis depends on biopsy and pathological examination.

Synovial sarcoma examination

Pathological manifestations

A false capsule formed by the reaction tissue can be seen on the large section of the intact diseased tissue, and there is a moderate amount of new blood vessels. The mass of the mass itself is uniform without lobulation or fiber spacing, and obvious hemorrhagic necrotic areas and highly basophilic calcification areas can be seen. The cell-rich mass is uniquely basophilic.

Under low magnification, the lesions are composed of cells rich in cells. There are usually two unique cell morphology, called biphasic morphology, one of which consists of malignant fibrous tissue cells that produce a small amount of collagen matrix, arranged in a slender shape. The squid is bone-like and very similar to fibrosarcoma. The presence of these cells is a cluster of epithelial-derived oval vesicular cells arranged in acinar, similar to cancer, in which areas are often visible. Cracks, which contain weakly dyed, uniform basophilic substances, which can be stained with mucin dyes, lined with tumor cells and without a basement membrane.

Under high power microscope, the shuttle formation consists of deeply stained spindle-shaped nuclei, which are common in mitosis. Sparse eosinophilic collagen is seen between cells. The epithelial or synovial components are composed of round or oval cells, and the cell membrane is not obvious. The nucleus is large and deeply stained with vesicles, and mitosis is common. These cells are often arranged in small acinar cells to present a glandular appearance. In some parts, this arrangement is so special that the cells arranged in adenocarcinoma are very well arranged. Similarly, the calcification zone is finely granulated and highly basophilic, interspersed between malignant synovial cells. The crack-like void contains mucin, which can be stained with various mucin dyes. Occasionally, the lesion is mainly composed of spindle cells. There are only a small number of synovial cells and mucin-rich "cracks" (ie, alveolar structures). This is difficult to distinguish from fibrosarcoma without special staining or electron microscopy. Synovial sarcoma.

Film degree exam

1.X-ray performance

About 30% of the lesions can be seen in the calcification, sometimes the periosteal reaction, or even the erosion of the bone or invading the bone, begins to appear only as a soft tissue mass, and calcification can occur in the posterior mass. For those with a little calcification in the lesion, consideration should be considered. Different from chondroma or hemangioma.

2. Bone scan

In the late stage of the scan, there is a limited increase in the amount of uptake around the active mineralization zone. Due to the rich neovascularization of the lesion, the lesions in the early stage of the scan are higher than the adjacent soft tissue.

3.CT

CT scan showed a soft tissue mass with uniform texture. The density was similar to that of skeletal muscle. The calcification in the lesion was highly suggestive of synovial sarcoma. The contrast agent was used to significantly enhance the lesion tissue.

The edge of the tumor is strengthened after injection of the contrast agent.

4.MRI

The lesion is often adjacent to an important neurovascular bundle. On the MRI image, there is a high signal, and the larger lesion signal intensity is uneven, suggesting a hemorrhagic and necrotic area.

Therefore these structures may be displaced or wrapped in the lesion.

5. Angiography

There are obvious neovascularizations in the reaction zone around the early arterial phase visible lesions, and in the late venous phase, significant staining is visible, as the lesions are often adjacent to the main neurovascular bundle.

Diagnosis and differentiation of synovial sarcoma

The differential diagnosis is mainly pathological identification. It is necessary to grasp the characteristic morphology of synovial sarcoma and to achieve biphasic differentiation, that is, there is a transition between the two types of cells.

The disease needs to be differentiated from fibrosarcoma. The misdiagnosis of synovial sarcoma is mainly caused by insufficient understanding. It is mostly confused with osteofibrosarcoma, malignant giant cell tumor, osteolytic osteosarcoma and joint tuberculosis.

The large-body synovial sarcoma colloidal tissue is a multi-liquid highly malignant synovial cell with many filamentous divisions, few glandular manifestations, many fissures, many mucus, and some fibroblasts are also prominent. In this case, synovial sarcoma can be distinguished from fibrosarcoma or undifferentiated sarcoma only by electron microscopy or by special histochemical staining.

It is often necessary to distinguish from adenocarcinoma, soft tissue acinar sarcoma, leiomyosarcoma, and schwannomas.

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