Intra-articular synovial lipoma of the knee joint.

We present a rare case of an intra-articular synovial lipoma, which was diagnosed in a patient after a knee trauma. MRI is the imaging modality of choice to suggest the diagnosis preoperatively, by demonstrating a well-delineated fat-containing lesion. The differential diagnosis of an intra-articular lipomatous lesion consists of lipoma arborescens and synovial lipoma.