You are asked to review a 68-year-old woman on the ward. She is complaining of pain and swelling in the left leg. Past medical history She had an anterior resection for a rectal tumor five days ago. Postoperative recovery has been unremarkable, and she has started to eat and drink and opened her bowels today. There is no history of trauma to the leg. Examination and investigations The abdomen is soft and non-tender.

The left leg is swollen to mid-thigh, with erythema of the skin. The calf feels warm and tender. The foot pulses are normal. Temperature : 37.5°C PR : 99/min Hb : 11.5 g/dL WCC : 16.7 × 10 9 /L Platelets : 360 × 10 9 /L Sodium : 143 mmol/L Potassium : 4.6 mmol/L Urea : 9.5 mmol/L Creatinine : 71 μmol/L C-reactive protein : 100 mg/L What is the most likely diagnosis? (Answer is posted in the comment section below!) *This case is from the Docplexus editorial team for educative…