What Causes Enlarged Leg With Bulging Veins In Calf?

I am 60 years old and in good health for the most part but I am probably 40 lbs overweight. A few years ago I noticed one leg was laarger than the other one. I am also getting some bulging veins in the calf of that leg. It gets a little bit larger as time goes by. I asked my doctor a few years ago about it but she seemed unconcerned. I am becoming concerned and would like to know what type of Physician I need to see. Thank you