Yоu аre evаluаting a 45 year оld patient with a swоllen left leg from the thigh to the toes. The patient did not experience any trauma to the leg and reports the swelling gradually increased over the last 15 months. The swelling is non-pitting, with hyperkeratosis with weeping superficial ulcers primarily below the knee. Medical history includes a femoral DVT. His socks and pants are wet from drainage. The leg is not red or hot, and the patient indicates that his leg just feels “heavy.” What is the MOST likely origin of the swelling?