Intra-articular chromic phosphate (³²P) in the treatment of diffuse pigmented villonodular synovitis

Pigmented villonodular synovitis (PVNS) is an uncommon proliferative lesion of synovial tissue. In diffuse PVNS, recurrence rates are high after resection alone. Adjuvant external beam radiation therapy contributes to improved local control. Limited data exist for intra-articular radioisotope therapy after surgical resection. We report institutional experience with intra-articular chromic phosphate ((32)P).

Records were reviewed from the Department of Radiation Oncology at Indiana University. Nine cases of PVNS treated with (32)P were identified (mean age=40). Seven patients were treated at time of recurrence and 2 patients were treated prophylactically. Intra-articular injections were performed by accessing the joint space, aspirating joint fluid, reinjecting 1-2 mCi of (32)P, and barbitaging to ensure good distribution in the joint space. No external beam radiation therapy was delivered. One patient was lost to followup. Mean followup of remaining patients was 20 months (range, 2-48).

Eleven injections were performed in 9 patients. Eight had PVNS in the knee(s) and 1 patient had involvement of the hip. Two patients were treated more than once, one for a recurrence in the same joint at 13 months and another for PVNS of a contralateral joint. Three clinical recurrences (2, 13, and 28 months) were noted. Two of three recurrences were in patients who had bulky diffuse PVNS at the time of injection. Overall local control was 70%. In patients without bulky diffuse PVNS at the time of injection, local control was 88%.

We report success using intra-articular injections of (32)P after synovectomy in patients with PVNS.