Pigmented villonodular synovitis.

Seventy-three patients, 28 males and 45 females, diagnosed with pigmented villonodular synovitis (PVNS) between 1982 and 1990 were followed for an average of 42.2 months (range, 21 to 108 months). Fifty-five cases occurred in the tendon sheath and eighteen in synovial joint. Ages ranged from 5 to 77 years, with an average of 38.9 years. The clinical presentations included chronic tumescence, serosanguinous arthrocentesis and painful limitation of range of motion. Plain roentgenography usually demonstrated soft tissue swelling with varying density, bony erosion or joint space narrowing. Arthrography and magnetic resonance imaging both gave specific pictures, with good diagnostic rates. The therapeutic regimen consisted of marginal excision for tendon sheath lesions and total synovectomy for intraarticular lesions. Extensive synovectomy with prosthesis replacement yielded good functional results in elderly patients with PVNS and cartilage destruction. Recurrence rate averaged 26% and was higher among knee joint lesions (33%), possibly because of inaccessibility of the popliteal fossa and inadequate excision of the lesion. Differences in the mitotic index between recurrence and non-recurrence groups had no statistical significance. This phenomenon may well serve against "tumor origin" as the etiology of this disease.