Pigmented villonodular synovitis

Introduction to pigmented villonodular synovitis Pigmented villonodular synovitis is relatively rare, with both villus and nodular. The patient is young and middle-aged. The age is between 20 and 40 years old. The disease occurs in the knee joint and the ankle joint. The hip, intercondylar, wrist, elbow and other joints are also seen in the bursae and tendon sheath. The disease may be a synovial disease between inflammation and benign tumors. Among them, the villus type is more similar to inflammation. basic knowledge The proportion of sickness: 0.00325% Susceptible people: no special people Mode of infection: non-infectious Complications: giant cell tumor of bone

Causes of pigmented villonodular synovitis

Cause (80%):

The disease may be a synovial disease between inflammation and benign tumors, in which the villus type is more similar to inflammation, and animal experiments have shown that multiple injections of blood into the joint cavity can produce the same pathological changes as the villus type. Athletes may have similar changes due to multiple knee joint hemorrhage. The nodular type is composed of a large number of synovial cells. If the resection is not complete, it is easy to relapse, so it is similar to benign tumor.

form:

The villus type is affected by a dark red or brownish yellow, often thickened, up to 1cm, the surface of the synovial membrane is uneven, often with wrinkles and fluff formation, and some fluffy slender, up to 1 ~ 2cm, in The water floats like a whisker; some have short tufts and fuse into nodules. The diameter of the nodules varies from 1cm to 4-5cm. The smaller nodules are reddish brown, and the larger nodules are yellowish white. With rust spots, the nodules are slightly hard and tough, the spiral fiber structure can be seen on the section, occasionally mucus degeneration and fissures, and some cases have both villus and nodular lesions.

distributed:

According to the distribution range of lesions, it can be divided into two types: diffuse and localized. It is diffuse and common, and a few are localized. In diffuse lesions, villi and villi are nodular. In localized cases, they are generally knots. Section type.

Pigmented villonodular synovitis prevention

This disease is caused by the chronic effects of other diseases. For example, athletes may have similar changes due to multiple knee joint hemorrhage. Therefore, the prevention of this disease is mainly to prevent joint damage. Treatment, early correct diagnosis and treatment are effective measures to improve the efficacy and restore the joint function of patients. Pay attention to adjusting the diet structure, pay attention to eating more fresh vegetables, supplement various vitamins, should not simply eat light foods, should be combined with alizarin, eat plenty of food, drink plenty of water, maintain the body's nutritional balance, enhance the body's immunity.

Complications of pigmented villonodular synovitis Complications of giant cell tumor of bone

Pigmented villonodular synovitis is an idiopathic proliferative lesion involving the joint synovium, joint capsule and tendon sheath. It can be focal or diffuse, most common in the knee joint, followed by the hip joint, involving young patients. In the knee joint, the entire synovial membrane is involved, and the humerus is eroded under the armpit. At this time, the subchondral granuloma can be seen, with a diameter of 3 mm, similar to giant cell tumor of the tibia. The fracture of the femur is visible in the intercondylar fossa cortex, diffuse pigmentation. Due to the proliferation of a large number of synovial tissue, the villus nodular synovial membrane leads to increased pressure in the joint. The villi easily invade the cancellous bone through the joint cartilage, the junction of the bone and the joint or the attachment of the ligament. The bone tissue invasion is more common in the hip and ankle joint. Because the joint of the knee joint is wide, the bone tissue is not easily pressed, and bone destruction is rare.

Pigmented villonodular synovial inflammation symptoms Common symptoms Joint swelling Muscle atrophy Joint fluid exudation Joint capsule Relaxation Joint capsule injury

There is no obvious systemic symptoms in this disease. The patient's body temperature is not high, the blood sedimentation is not fast, the blood picture is not changed, and the local symptoms are mild in the early stage. Therefore, the patient visits later and the disease period is longer. The general disease period is 1 to 5 years. More than half of the patients have a history of trauma. The main symptoms are joint swelling, mild pain, local skin temperature sometimes slightly higher, joint function limitation is not obvious, diffuse swollen joints, and the thickened synovial membrane is sponge-like. It feels that the effusion can touch the sense of fluctuating, and sometimes it can touch the nodules of different sizes and slightly moving.

When the knee joint is involved, the upper sac and the sacral bones are swollen, and the effusion test is positive. The hyperplastic synovial tissue can sometimes penetrate the posterior capsule and enter the armpit, and spread down the muscle space along the back of the calf, resulting in deep In the diffuse swelling, swelling of the ankle joint, the most obvious around the external hemorrhoids, swelling in the hip joint is mostly in front of the hip joint.

Whether it is diffuse or limited, the affected limb has mild muscle atrophy, joint puncture can draw hemorrhagic or brown liquid, this joint fluid is very special and has diagnostic value.

Examination of pigmented villonodular synovitis

The main methods of examination for this disease are as follows:

1, X line

X-ray plain film signs of this disease include joint swelling and joint bone erosion damage, soft tissue swelling is nodular, high density, PVNS bone erosion mostly begins at the junction of bone and cartilage, so joint space generally remains normal, but joint product When the amount of fluid is large, the joint space can be widened; when the secondary joint degeneration or the articular cartilage is obviously eroded, the joint space can be narrow.

2, CT

It is a cross-sectional imaging with high density resolution. It is superior to X-ray plain film in showing soft tissue mass in joint cavity, joint effusion and bone erosion. It shows that the hardening edge around bone defect is also better than X-ray film. Sensitive, CT-enhanced scan can show irregular thickening of the synovial membrane, which can help the diagnosis of PVNS, but CT shows the characteristics of joint capsule, articular cartilage, soft tissue and other diseases, and when the lesion has obvious bone erosion, It has great significance. Therefore, CT diagnosis is of limited value when PVNS is used early or without bone erosion.

3, MRI

The high resolution of the tissue can show the whole shape, type and tissue composition of the lesion. The typical manifestation of PVNS is T1WI and T2WI have low signal. The pathological basis of this feature is the deposition of hemosiderin in the nodule, but the early joint of the lesion There is only bleeding in the body, no or less hemosiderin deposition in the nodules, and the hemosiderin in the late stage of the lesion is reduced by absorption and transport. Therefore, this signal characteristic does not penetrate the whole process of the lesion.

4, laboratory inspection

Under the microscope, the surface of the villi is several layers of synovial cells, the center of which is a little fibrous tissue, dilated capillaries and a small amount of inflammatory cells. The hemosiderin particles are visible inside and outside the cells. The nodules are composed of dense synovial cells. Less pulp, unclear cell membrane, deep nuclear staining, fissures and nipples in dense cells, occasional multinucleated giant cells and foam cells between synovial cells.

Diagnosis and differentiation of pigmented villonodular synovitis

diagnosis

The disease is carefully analyzed for clinical manifestations, combined with joint fluid and X-ray examination, the diagnosis is generally no difficulty.

Differential diagnosis

The pigmented villonodular synovial membrane needs to be differentiated from joint diseases that can cause joint swelling, joint effusion, and joint bone destruction. The soft tissue swelling of pigmented villonodular synovitis is a nodular shape with high density and joints. Mainly in the cavity, no osteoporosis, hardening of the edge of the bone defect, normal joint space helps to distinguish from joint tuberculosis, synovitis, synovial sarcoma, rheumatoid arthritis and other diseases, calcification is more common in tuberculosis, slippery Membrane sarcoma, but can not completely rule out pigmented villonodular synovitis, calcification should be comprehensively analyzed in all signs, in order to reduce misdiagnosis.

1 Charcot's joint: joint swelling, effusion, painless, etc. in the early stage, but most have a history of trauma, joint deformity is more serious, new bone formation seen on X-ray, disintegration of bone end, joint surface destruction, joint dislocation and other bones Joint damage is highly inconsistent with clinical symptoms.

2 synovial sarcoma: both have soft tissue mass, calcification, bone destruction, but synovial sarcoma develops rapidly, short course, severe pain, bone destruction is soluble, no hardened edge.

3 synovial tuberculosis: both have swelling around the joint tissue, joint surface destruction, early expansion of the joint stenosis in the early stage of the joint space, the obvious point of tuberculosis has obvious osteoporosis, joint surface damage involving both sides, no hardened edge, soft tissue No swelling.

4 types of rheumatoid arthritis single joint type: more common in the elbow, wrist, knee, knuckle, joint swelling, soft tissue thickening, pain is not obvious, early osteoporosis, joint space narrowing or even worm-like damage, The joint is pierced as a transparent liquid.

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