Giant Baker's cyst associated with pigmented villonodular synovitis: surgical management of a rare case

Abstract

This case report presents a rare instance of pigmented villonodular synovitis in conjunction with a large Baker's cyst. A 48-year-old female patient presented with progressive pain, swelling and limited range of motion in the right knee. Magnetic resonance imaging revealed a giant Baker's cyst measuring approximately 11.5 × 8 cm. This was consistent with the presence of multiple lobulated and septated cystic structures. The largest of these measured 7.5 × 5 cm and was located in the popliteal fossa. Proliferative synovial changes suggestive of pigmented villonodular synovitis were also noted in the synovium. Following the failure of conservative treatment, the cyst was excised via a posterior approach and an arthroscopic synovectomy was performed simultaneously. Pathological examination confirmed the diagnoses of a Baker's cyst and pigmented villonodular synovitis. There were no complications postoperatively, and the patient achieved a full range of motion in her knee and was able to resume her daily activities without pain. This case highlights the importance of considering pigmented villonodular synovitis in the diagnostic process for large, complicated Baker's cysts, and demonstrates that surgical excision combined with arthroscopic synovectomy is an effective, safe treatment approach.