Massive iliofemoral or IVC occlusion with patent arteries
Extensive vascular congestion and<unk>  ischemia
Involves superficial collateral veins
40-60% of phlegmasia cerulea dolens with capillary involvement progress to<unk> 
Age 50-60s
Malignancy (over half)
Thrombophlebitis migrans
Acquired hemolytic anemia due to cold-antibodies
Typical risk factors for DVT (pregnancy, surgery, trauma, hypercoagulable syndrome)
Idiopathic
Venous gangrene
Deep venous thrombosis 
Wet gangrene
Phlegmasia alba dolens
Dry gangrene
Phlegmasia cerulea dolens
Fournier gangrene
Necrotizing cellulitis