Imaging Features of Pigmented Villonodular Synovitis with Emphasis on Sonographic Findings

J. Lin MD, W.J. Weadock, MD, T.J. Quinn MD, J.A. Jacobson MD, D.A. Jamadar MBBS, J.H. Ellis MD

University of Michigan, Ann Arbor Michigan

 

Case III: 29 year old female with focal PVNS of the right knee

Image F: Axial T1-weighted MR image shows an ovoid, 1.5cm nodule anterior to the trochlear laterally (arrows). The mass exhibits homogeneous low signal intensity.

Image G: Axial T2-weighted image at the same level shows diffuse low signal intensity in the mass (arrows), which is slightly higher in intensity than image F.

Image H: Sagittal STIR image shows high signal throughout the mass which is in an intra-articular location, just inferior to the patella (arrows).

 

  • This case illustrates focal PVNS. The synovial involvement of PVNS has been classified into localized and diffuse forms.

  • The nodular masses of PVNS are characteristically of low signal intensity on T1-, T2-, and PD-weighted imaging. The low signal is a result of the presence of hemosiderin within the tissue.

  • In our experience, diffusely increased signal intensity is seen within PVNS lesions on STIR images. Little has been written about this finding. We speculate that edema within the inflammatory synovitis takes precedence over the presence of hemosiderin in the tissue in this extremely water sensitive sequence.