What Causes Numbness Patch On Upper Right Leg?

I have a numbness patch on my upper right leg from the side of my knee upward about 6 inches long and about 4 inches wide. It's been there for several months now. I also have extreme swelling in this leg also my cardiologist has me on diuretics and compression stockings just recently during working hours as I sit a lot and am on the 46th floor of a high rise. Is the numbness something to be concerned about? I do have RLS and Aortic Valve Stenosis and am overweight. I am a 51 yr old female