Recurrent tenosynovial giant cell tumor

Sagittal noncontrast MRI of the knee (T2 fat-saturated sequences) of a large tenosynovial giant cell tumor, recurrent despite multiple surgeries. There is erosion of the cartilaginous surfaces, damage to and invasion of a portion of the distal femur (arrow), and a large volume of intra-articular (dashed arrows) and extra-articular disease (thick arrows).