Lipoma arborescens or villous lipomatous proliferation of the synovium is a rare lesion. We describe the in vivo imaging characteristics of lipoma arborescens of the knee utilizing fat suppression techniques and contrast medium administration. As expected, the lesion demonstrated signal loss when utilizing fat suppression. In addition, no contrast enhancement was noted. When a synovial process demonstrates isointensity with subcutaneous fat on all pulse sequences and no contrast enhancement, lipoma arborescens should be the primary diagnosis consideration.