Presentation
Knee swelling and chronic pain
Patient Data
MRI typically shows large joint effusion with multiple foci of low signal intensity within the joint space, and extensive mass-like synovial proliferation with low signal intensity on T1-WI and low to intermediate signal on T2-WI and high signal intensity on PD sequences. Multiple osseous erosions are seen.
Case Discussion
Imaging findings are characteristic of recurrence of a pathologically proven pigmented villonodular synovitis (PVNS). PVNS is a rare synovial disorder but the features of this disease on MRI is unique, The characteristic blooming seen on GRE images and low T1 and T2 signal intensity reflect the hemosiderin-laden synovial tissue.
Recurrence is more frequent with diffuse intra-articular PVNS, and adjuvant radiation therapy may be useful.
Editor's note: Per the 2020 WHO Soft Tissue and Bone Tumors Classification (5th ed.), the recommended terminology is tenosynovial giant cell tumor with pigmented villonodular synovitis no longer recommended (although remains in common use).