COMPUTED-TOMOGRAPHY AND MAGNETIC-RESONANCE-IMAGING OF DIFFUSE PIGMENTED VILLONODULAR SYNOVITIS - REPORT OF A CASE

We describe the computed tomographic (CT) and magnetic resonance imagi ng (MRI) features of a surgically proven case of diffuse pigmented vil lonodular synovitis (PVNS) of the knee in a 34- year-old woman. A comp lex mass consisting of solid and multicystic components was clearly de monstrated by CT and MRI. The solid part showed homogeneous hypodense attenuation relative to adjacent muscles on CT scans, but it showed in homogeneous signal intensity on spin echo T1- and T2-weighted images ( WI). The solid component enhanced homogeneously on CT scans but hetero geneously on MR images. Multiseptated enhancement of the cystic compon ent on both CT and MR images were displayed. All of the above features were better demonstrated on MRI. Multiple marked hypointense round an d patchy areas, and also a few areas isointense to subcutaneous fat wi thin the lesion were also found on T1WI, proton density WI and T2WI. T hese characteristic MRI features of PVNS correlated well with its hist ologic structures: depositions of hemosiderin and fat in the prolifera tive synovial villi and bloody cystic content. These features may help to distinguish PVNS from other disease entities arising from the syno vium.