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Unilateral calf swelling

      1. Indication

      An 81-year-old man presented to the emergency department with left calf painful swelling for 4 days. He has a history of hypertension and ischemic heart disease. He denied any injury. Physical examination was remarkable for left calf tender swelling, and ecchymosis around left ankle (Fig. 1). Compression ultrasonography excluded deep vein thrombosis.
      Figure thumbnail gr1
      Fig. 1Ecchymosis beneath the medical malleolus.
      What is the diagnosis?

      2. Diagnosis

      Ultrasound of left knee confirmed a ruptured popliteal cyst.
      A common mimicker of deep vein thrombosis is a ruptured popliteal cyst. Popliteal cysts are synovial outpouchings of the knee joint, usually due to arthritis. If ruptured, bleeding would dissect down the calf muscles and reach the ankle in a few days, causing a characteristic crescent-shaped ecchymosis beneath the malleolus [
      • Kraag G.
      • Thevathasan E.M.
      • Gordon D.A.
      • Walker I.H.
      The hemorrhagic crescent sign of acute synovial rupture.
      ]. The presence of this sign is strong evidence against deep vein thrombosis.

      Conflict of interest

      The authors report no conflict of interests regarding this work.

      Reference

        • Kraag G.
        • Thevathasan E.M.
        • Gordon D.A.
        • Walker I.H.
        The hemorrhagic crescent sign of acute synovial rupture.
        Ann Intern Med. 1976; 85: 477-478