Abstract：Objective: To study the imaging features and the pathologic changes of pigmented villonodular synovitis(PVNS) of the knee joint. Methods: MRI, ultrasonography and X-ray appearances in 19 cases with PVNS of the knee joint were studied retrospectively, and were compared with surgical and pathological findings. Results: Nineteen cases of PVNS were diffuse form. The fundamental pathological alteration is idiopathic proliferation of synovial tissue and deposition of hemosiderin within villondules; In all the cases, thickened synovium seen in MRI(19/19), ultrasonography(19/19), X-ray(0/19); knee joint effusion seen in MRI(19/19), ultrasonography(19/19), X-ray(6/19); soft tissue nodule in joint space seen in MRI(19/19), ultrasonography(19/19), X-ray(11/19); erosion of fat pad in joint space in MRI(12/19), ultrasonography(0/19), X-ray(0/19); destruction of meniscus and cruciate ligment seen in MRI(9/19), ultrasonography(3/19), X-ray(0/19); erosion of cartilage and bone seen in MRI(11/19), ultrasonography(3/19), X-ray(5/19). Conclusion: MRI is the perfect examination means for the PVNS.
2007, Vol. 18 
