A 40-year-old man with metastatic colorectal cancer (peritoneum and lymph-node metastases) under therapy with palliative chemotherapy, with a previous history of deep venous thrombosis in the lower left leg complained to the assistant physicians of sudden worsening of the symptoms despite optimal anticoagulation with warfarin (International normalised ratio [INR]: 3,87). In the physical examination, the patient presented extreme pain followed by severe swelling, blue discoloration, and paresthesia in the lower left extremity (Fig. 1).
