Common femoral vein canal lipoma causing chronic unilateral lower limb swelling

A 64-year-old woman presented to vascular clinic with a 2-year history of right ankle swelling, associated with pain on walking. Initial venous duplex imaging showed no obvious cause. Further imaging showed a lipoma compressing the common femoral vein. We consider the relative merits of the imaging modalities of the groin and the literature available on lipomas causing compression.