Pigmented villonodular synovitis

Introduction to pigmented villonodular synovitis Pigmented villonodular synovitis (PVNS) is a proliferative lesion of the synovial membrane that often manifests as a localized nodule. The mass may originate from the synovial membrane, tendon sheath, fascia or ligament tissue. The lesion appears as a painless soft tissue mass, usually at the finger and toe, and also in other joints (especially the knee joint) and the tendon sheath. Single joint disease is a regularity of this disease, but there are also rare multiple joint lesions. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: joint pain

Causes of pigmented villonodular synovitis

(1) Causes of the disease

The cause is unknown, some researchers believe that the disease is an inflammatory reaction, and some people think it is a tumor.

(two) pathogenesis

The pathogenesis is still unclear and may be an inflammatory response or a pre-neoplastic manifestation.

Pigmentation of villonodular nodular synovitis

1. Eliminate and reduce or avoid the disease factors, improve the living environment, improve the development of good habits, prevent infection, pay attention to food hygiene, and rational diet.

2. Pay attention to exercise, increase the body's ability to resist disease, do not fatigue, excessive consumption, quit smoking and alcohol.

3. Early detection and early diagnosis and early treatment, and establish confidence in the fight against disease.

Pigmented villonodular synovitis complications Complications joint pain

Can be complicated by joint bloody effusion, bone destruction.

Pigmented villonodular synovial inflammation symptoms Common symptoms Joint pain nodules Synovial black stained joint swelling

The lesions are characterized by painless soft tissue masses, usually located at the fingers and toes, and also in other joints (especially knee joints) and tendon sheaths. Single joint disease is a regularity of this disease, but there are also rare multi-joint lesions, clinical Often manifested as painless swelling or mild pain with swelling of the joints, occasionally acute joint pain and swelling, patients may also have joint lock and other symptoms, for young patients with unexplained hip pain should be considered PVNS Possibly, PVNS has two manifestations: diffuse and nodular, nodules are most common in the hand, diffuse is most common in the knee, and PVNS is also found in the hip, ankle, and elbow joints.

Diffuse type

(1) The lesion can be expressed as active or inactive.

(2) On the X line, bone erosion around the joint can be seen.

(3) A diffuse mass can be found in the physical examination.

2. Nodular type

(1) Less common than diffuse type.

(2) Bone destruction in the absence of diffuse type.

(3) can cause repeated joint bleeding, but the joint pumping fluid can be in a normal color (ie, not a typical tan).

Limited nodular synovitis should be distinguished from diffuse pigmented villonodular synovitis, which usually involves larger joints, especially in the knee joint.

The macroscopic lesion specimen is brown, which is caused by extensive hemosiderin deposition. This disease is often accompanied by bloody effusion of the joint, causing some observers to believe that the disease is a vascular abnormality, and the nodular synovium Inflammation is a true tumor or a reactive disease, so the two are different, but the difference between the two is not histologically obvious, so some authors use "pigmented villonodular synovitis" "This name includes both types of synovial lesions.

Examination of pigmented villonodular synovitis

1. Blood routine, erythrocyte sedimentation rate, rheumatoid factor and C-reactive protein examination, no significant changes.

2. Joint puncture examination The joint fluid is mostly bloody, and it can also be orange.

3. X-ray film appearance of X-ray PVNS depends on the location of the lesion.

The nodular PVNS of the hand can be characterized by soft tissue swelling and bone erosion. The bone destruction zone has a well-defined hardening margin. This bone destruction is the result of direct spread of the lesion and compression of the adjacent bone, and does not suggest malignancy.

Diffuse intra-articular pigmentation of villonodular synovitis can cause joint effusion, usually the joint space is normal and there is no osteoporosis or only mild osteoporosis, and the bone around the joint can be seen in different sizes. Erosion, bone erosion is more common in tight joints such as the hips, elbows and wrists.

Although cartilage and bone metaplasia can be seen in the inner layer of the synovium in some rare cases, calcification is not typical of this disease.

On X-ray films, localized nodular synovitis should be differentiated from other soft tissue tumors and tumor-like diseases.

4. CT CT scan can show hemosiderin, the extent of synovial lesions, and the cystic and erosive condition of the bone. If there is extensive hemosiderin deposition, it shows an increase in density on CT.

5. MRI On the T1 and T2 weighted images, hemosiderin showed low signal or no signal. The most typical MRI feature of PVNS is the nodularity of intra-articular low signal on T1, T2 and proton images. Tumors, lesions, and focal masses showed the best on T2-weighted images, showing a low-signal area due to hemosiderin deposition, a low signal on T1-weighted images, hemorrhagic synovitis May be confused with PVNS.

4. Angiographic angiography showed that the blood supply of the lesion was abundant, but in the late stage of the lesion or the fibrosis of the lesion, angiography showed that the lesion had less blood supply.

6. Pathological performance

(1) Seen by the naked eye: The joint fluid of most patients is bloody, brown, and the lesion is a mass composed of villi and synovial folds. It is tan, and the lesion may be fixed without pedicle or composed of several pedicled nodules. The lesion passes through the joint capsule to erode the bone, and the confined PVNS appears as a pedicled hard nodule.

(2) Seen under the microscope: PVNS is characterized by synovial cell proliferation on the surface of the synovial membrane and under the synovial membrane. Visible villi and nodules can be seen under low magnification, and diffuse cells (matrix) can be seen under high magnification. At the same time, it is accompanied by fibroblasts, multinucleated giant cells, xanthomatic cells, lymphocytes and unequal amounts of hemosiderin deposition. Due to the diversity of histological features, there are many names for this disease: giant cell tumor of tendon sheath, tendon sheath fiber. Tumor, tendon sheath fibrin, sphincter flavin and so on.

Pathological identification should include: Hemosiderotic synovitis, rheumatoid arthritis and synovial chondromatosis.

Diagnosis and differentiation of pigmented villonodular synovitis

According to the clinical lesions, the painless soft tissue mass is usually located at the finger and toe, and can also be seen in other joints (especially the knee joint) and tendon sheath. The regularity of single joint disease can be diagnosed by arthroscopy and pathology.

Differential diagnosis

1. Diffuse pigmented villonodular synovitis must be associated with idiopathic synovial osteochondromatosis (visible calcification and ossification), infection (visible osteoporosis, reduced joint space, unclear boundary of bone destruction area) And the identification of other joint lesions.

2. Different from rheumatoid arthritis (RA), RA often invades multiple joints. PVNS usually manifests as single joint hemorrhagic arthritis. Single joint disease is a regular disease of this disease, but there are also rare multiple joint lesions.

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