What Causes A Feel Of Severe Hardness In Leg And Swelling Of Calf Muscle?

What would make a person s leg so extremely hard to the touch to the point that the leg feels like its not real? It feels like a piece of wood. The ultrasound of the leg was negative for DVT.The pulse was absent and we are about to go for an arterial Doppler.My family member who has this problem is 100 years old! No pain. There is some swelling in the calf and on the sides of the knee.