Pigmented Villonodular Synovitis
October 19, 2008 by Dr Arun Pal Singh
Filed under Joints
In this disease, the synovial membrane proliferates and its surface develops nodules and villi. It also turns into brown colour.
The cause of the condition is unknown. It is thought to be an inflammatory process. It occurs most commonly in young adult.
Two primary forms are described
- Diffuse form that affects the entire synovial lining
- Localized form.
The diffuse form is most common and involves the large joints, while the localized form typically occurs around the small joints of the hands and feet.
The disease is monoarticular mostly i.e. it confines to a single joint. The knee joint is the most commonsite of affliction. It is followed in decreasing order of frequency in the fingers, feet, ankles, hips, wrists, and shoulders.
Pathology
Gross features are thickened synovium, with a combination of villous and nodular proliferatio. Microscpically Pigmented Villonodular Synovitis is characterized by the presence of hemosiderin-laden, multinucleated, giant cells. Lipid-laden macrophages, fibroblasts, and other large, polyhedral-shaped, mononuclear cells may also be seen. The lesion is very vascular and shows synovial hyperplasia.
The presence of hemosiderin is responsible for pigmentation.
The lesion can invades local tissues including the invasion of the subchondral bone, with resultant cyst formation which is a characteristic finding.
Symptoms
- Painless swelling to begin with
- Pain and swelling of the affected joint develop as the disease progresses
- Swelling is disproportionate to degree of pain
- Locking of the joint when synovial membrane may get caught between the articular bone ends
- Limitation of joint motion is common.
Examination
- Nodular or diffuse joint swelling.
- Temperature of the welling might be raised
- Swelling tender to palpation.
- On aspiration of the affected joint, a dark brown or frankly serosanguinous fluid is obtained
Radiological Findings
- Irregular synovial thickening.
- Erosions of the articular ends of the bones
- Cysts
Long-standing pigmented villonodular synovitis may extensively involve the distal end of the femur with lytic lesions without apparently involving the tibia in the plain radiograph.
The diseased tissue penetrates bone by infiltrating and extending through the vascular foramina.
Angiography shows richly vascularized tumor like lesions.
Differential Diagnoses
- Chronic monarticular rheumatoid arthritis
- Synovial hemangiomatosis
- Low-grade infectious arthritis
- Tuberculosis
- Gout
- Hemochromatosis
- Synovial Osteochondromatosis
- Synovial Sarcoma
Treatment
Total synovectomy if possible should be done. Arthroscopic surgery is preferable ove open surgery. Proneness of recurrence should be explained to the patient.
In recurrent cases with extensive bone involvement and joint destruction, radiation therapy in relatively small doses over a period of two to three weeks may be indicated.
A long course of the disease and numerous recurrences may necessitate amputation.
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