What Is Pigmented Villonodular Synovitis?

Pigment villous nodular synovitis (PVNS) is relatively rare, there are two types of villi and nodular. The patient was mostly young and male. Most are between 20 and 40 years old. The disease occurs in the knee and ankle joints, followed by the hip, intercondylar, wrist, and elbow joints, and occasionally seen in the bursa and tendon sheath.

Basic Information

English name

pigmented vil-lonodular synovitis

Visiting department

orthopedics

Multiple groups

20 to 40 year old men

Common locations

Knee and ankle

Common symptoms

Joint swelling and pain

Causes of pigmented villous nodular synovitis

This disease may be a synovial disease between inflammation and benign tumors. The villous type is more similar to inflammation. Animal experiments prove that repeated repeated injections of blood into the joint cavity can produce the same pathological changes as the villous type. Similar changes may occur in athletes due to multiple knee joint bleeding. The nodular type is composed of a large number of synovial cells, and it is easy to relapse if it is not completely removed, so it is approximately benign tumor.

Clinical manifestations of pigmented villous nodular synovitis

The disease has no obvious systemic symptoms. The patient's body temperature is not high, the erythrocyte sedimentation rate is unsatisfactory, and the blood picture remains unchanged. Local symptoms are also mild in the early stage, so the patient is seen late and the disease period is longer. Generally, the disease period is the most in 1-5 years, and more than half have a history of trauma. The main symptoms are joint swelling, pain is relatively mild, the local skin temperature is sometimes slightly higher, and joint function is limited. The joints were diffusely swollen, and the thickened synovium was felt like a sponge, with a lot of fluid that could be touched and fluctuated. Sometimes nodules of varying size and slight movement are palpable.

When the knee joint is involved, the palatal sac and sacrum are swollen obviously, and the floating palate test with more fluid is positive. Proliferated synovial tissue can sometimes penetrate the posterior joint capsule and enter the popliteal fossa, and spread downward along the posterior calf muscle space, resulting in deep, diffuse swelling. The swelling of the ankle joint is most obvious around the medial and lateral malleolus. When the hip joint is involved, the swelling is mostly in front of the hip joint.

The affected limb has mild muscle atrophy. Arthrocentesis can draw hemorrhagic or brown fluids. This joint fluid is special and has diagnostic value.

Pigmented villous nodular synovitis

1.X-ray plain film

X-ray plain signs of the disease: joint swelling and joint bone destruction. Soft tissue swelling is nodular and denser; PVNS bone invasion usually starts at the junction of bone and cartilage, so the joint space generally remains normal. However, when the amount of joint fluid is large, the joint space can widen; when secondary joint degeneration or joint cartilage is significantly invaded, the joint space can be narrowed.

2.CT inspection

Cross-section imaging has higher density resolution, and is significantly better than plain radiographs in displaying soft tissue masses, joint effusions, and bone invasion in the joint cavity. It is also more sensitive than plain radiographs in displaying the sclerotic margin around bone defects .

3. Magnetic resonance (MRI)

Tissue resolution is high, and it can show all the morphology, types and tissue components of the lesion.

4. Laboratory inspection

Under the microscope, there are several layers of synovial cells on the surface of the villi, with a small amount of fibrous tissue, dilated capillaries, and a few inflammatory cells in the center. There are hemosiderin-containing particles inside and outside the cell. Nodules are composed of dense synovial cells with less cytoplasm, unclear cell membrane, and deeper nuclear staining. Fissures and nipples are visible in dense cells. Occasionally, synovial cells are multinucleated giant cells and foam cells.

Diagnosis of pigmented villous nodular synovitis

The clinical manifestations of this disease are carefully analyzed and combined with joint fluid and X-ray examination, diagnosis is generally not difficult.

Pigmented villous nodular synovitis treatment

Surgical removal

Surgical resection is relatively thorough, especially for nodular cases. Radiation therapy is better for the villous type and less effective for the nodular type. Diffuse lesions should be resected in order to avoid recurrence.

2. Radiation therapy

Radiation therapy after surgery can also achieve the purpose of cure. For diffuse nodular lesions of the knee joint, the knee ligaments and lateral collateral ligaments should be cut. After dislocation of the joints, the anterior and posterior synovial tissues are completely resected. If the nodular lesions are not completely removed, they will easily relapse In addition, there are a few cases of patients with synovial sarcoma. For localized lesions, only local synovial tissue can be removed.