Localized pigmented villonodular synovitis of the right knee: a rare case report from Burkina Faso

Villonodular synovitis is a rare disease with an estimated incidence of 2 to 8 cases per million per year in the general population. We present a case of pigmented villonodular synovitis of the right knee treated by arthroscopic synovectomy. It was about a 52-year-old patient admitted for chronic right-sided mechanical knee pain (evolving for 2 years) of progressive onset. Puncture of the right knee yielded approximately 375 cc of serohematous fluid. As the effusion recurred, an ultrasound scan of the right knee was performed, showing a large fluid effusion containing numerous villonodular formations that showed up on the doppler in places, mostly in the sub-quadricipital recess. An arthroscopic synovial biopsy was performed, and the anatomopathological examination led to the diagnosis of localized villonodular synovitis of the right knee. There was no recurrence after arthroscopic total synovectomy. Villonodular synovitis is rare. It should be considered in the presence of recurrent serohematous effusion of the knee. Received: April 5th, 2025 Accepted: June 15th, 2025 https://dx.doi.org/10.4314/aamed.v18i4.20