Successful treatment of relapsing Pigmented Villonodular Synovitis (PVNS) of the knee with radiosynoviorthesis

PVNS is a rare disorder characterised by benign proliferation of synovial tissue. The treatment is surgical but relapse rate is high (8% to 46%). We report a 13 years old girl with PVNS of the left knee diagnosed in February 2003. Three months after diagnosis she underwent surgical synovectomy. Two years later important swelling of left knee with pain and limitation of movement developed and MRI confirmed the relapse of PVNS. She was treated with 3 intraarticular injections of etanercept two months apart with mild reduction of fluid but not of synovial hypertrophy. In November 2006 radiosynoviorthesis with one intraarticular injection of 186Re was performed. No side effects were reported and patient presented an important reduction of pain and improvement of range of motion. Six months after the procedure MRI showed marked decrease of fluid accumulation, and a mild reduction of synovial hypertrophy. One further intraarticular injection of 186Re has been performed 18 months after the first in order to obtain a more complete effect on synovial thickening.