A 45-year-old man complains of pain in the inner surface of the lower leg and thigh. Ill for 5 days, when after exercise there was pain in the lower leg, which gradually spread to the thigh. Objectively established: in the projection of the large subcutaneous veins on the leg and thigh there is redness of the skin and swelling. On palpationrevealed: compaction and soreness. Edema of the right lower extremity is absent, pulsation arteries in the feet is determined. What is the most probable pathology that causes this the picture?