Phlegmasia cerulea dolens is an uncommon severe form of deep venous thrombosis which results from extensive thrombotic occlusion (blockage by a blood clot) of the major and the collateral veins of an extremity. It is characterized by sudden severe pain, swelling, cyanosis and edema of the affected limb. There is a high risk of massive pulmonary embolism, even under anticoagulation. Foot gangrene may also occur. An underlying malignancy is found in 50% of cases. This phenomenon was discovered by Jonathan Towne, a vascular surgeon in Milwaukee, who was also the first to report the "white clot syndrome" (Now called HIT= Heparin induced thrombocytopenia)...