We describe a case of 30-year old male followed-up since the age of 6 for severe type of rare combination of polyarticular form of pigmented villonodular synovitis with hereditary malformation constellation consistent with Noonan-like syndrome. Within 20 years, the patient underwent repeated synovectomies of large joints with temporary effect only.
Radiation therapy with the dose of 30 Gy in 15 sessions has been applied for active aggressive synovitis of both knees associated with pain and progressive joint destruction. Favorable effect lasted for 3 years.
Progressive destruction with range-of-motion limitation required successive total joint replacement of both knee joints. Left knee prosthesis has been revised for aseptic loosening after 3.5 years.
It is now 5 years since the right knee primoimplantation and 3 years since the left knee reimplantation without signs of component loosening or recurrence, with satisfactory clinical and functional outcome.