Pigmented Villonodular Synovitis is an infrequent, benign proliferative disease of the synovial membrane that mainly affects large joints such as the knee. This case report presents a 46-year-old male with advanced right knee pain, swelling, and mechanical symptoms over more than a few months. Initial clinical assessment recommended intra-articular pathology without systemic involvement. MRI exposed diffuse synovial thickening with characteristic low signal intensity on T1- and T2-weighted images and blooming on GRE sequences due to hemosiderin deposition, confirming the diagnosis of diffuse PVNS. Arthroscopic synovectomy was performed using multiple portals to access the anterior and posterior compartments. This case importance of early MRI in diagnosing PVNS, the utility of arthroscopy for minimally invasive management, and the need for long-term follow-up due to recurrence risk. Advances in targeted therapy, such as CSF1R inhibitors, offer promise for recurrent or inoperable cases.

KEYWORDS: Pigmented Villonodular Synovitis, Knee Joint, Arthroscopic Synovectomy, Synovial Proliferation, MRI, CSF1R Inhibitors, Hemosiderin, Recurrence.