Pigmented villonodular synovitis. Review of 20 cases

Pigmented villonodular synovitis (PVS) is a rare aggressive lesion. Inclusion of this disease in the differential diagnosis of rheumatoid arthritis can lead to early diagnosis and treatment. In this retrospective study we evaluated diagnostic procedures, therapies, and outcomes of PVS.

Twenty surgically treated cases of PVS were evaluated: joint, 16; tenosynovial, 3; and bursa, one. The 20 patients had undergone the following surgeries: 4 total synovectomies, 2 subtotal synovectomies, eight arthroscopically assisted resections, 4 resections of extraarticular lesions, and 2 arthroplasties. The mean followup was 17.5 mo (1-54).

At diagnosis, pain was present in 19 of 20 cases. Joint swelling or a tumor was found in 11 cases, and 12 patients complained of repeated joint effusions. The mean duration of symptoms was 23.8 mo (range 1-144). Half the cases had a nodular pattern and the other half a diffuse pattern. The most common location of PVS was the knee (14 patients). Surgical treatment before admission did not always lead to an accurate diagnosis. For example, in 2 patients, arthroscopy did not reveal PVS. In 2 patients a soft tissue sarcoma was suggested. In 3 patients, the diagnosis was made incidentally with arthroscopy or arthroplasty. On radiographs, bone lesions were seen in 8 cases; in 13 of 17 cases the diagnosis was by magnetic resonance imaging (MRI). After surgery 17 patients stayed free of recurrence, 14 without symptoms. One patient who had an incidental diagnosis of PVS has a synovectomy planned as a second procedure. One patient awaits a second dorsal procedure after a ventral knee synovectomy. One patient shows recurrent disease 33 mo after resection of a nodular knee lesion.

PVS should be included in the differential diagnosis of any arthritis. MRI is the most effective diagnostic tool in identifying PVS. The treatment of PVS consists of surgical excision in sound tissue. A total synovectomy should be the treatment of choice in diffuse disease. From the literature, nonsurgical therapies, such as steroid injections, 90Y synoviorthesis, or external beam radiation, seem to be of benefit in selected patients.