What does altered marrow signal in distal femur and proximal tibia accompanied with hemosiderin deposition & thickened synovium in mri left knee mean?

Hemosiderin MRI: This may be consistent with a condition of the knee called pigmented villodular synovitis. This is caused by inflammation of the lining of the knee joint (synovium) and resulting deposit of breakdown of blood products. The cause is largely unknown. The diagnosis of pigmented villonodular synovitis is confirmed by biopsy, and the treatment of choice is synovectomy.

Possibly PVNS: Pigmented villonodular synovitis (pvns )is proliferative disorder that can affect joints, tendons and bursae with unknown etiology. Possibily chronic inflammatory response or a benign neoplasm of fibrohistiocytic origin. Major radiographic differential includes uncalcified synovial chondromatosis, tuberculous arthritis, hemophiliac arthropathy. Sometimes need biopsy to confirm pvns.