Phlegmasia Cerulea Dolens Due To May Thurner Syndrome.

May-Thurner syndrome is rarely considered in the differential diagnosis of deep vein thrombosis (DVT). Patients present with a clinical picture suggestive of DVT, and the true diagnosis is not confirmed until CT venography. We present a case of a 71-year-old woman, with risk factors of hypercoagulability, such as an anatomical variant and a 50-pack-year history, who presented with sudden onset swelling and redness of her left leg. Further investigation led to a diagnosis of May-Thurner syndrome. Our case discusses this extrinsic cause of venous stasis and how early diagnosis, and treatment can prevent the progression into Phlegmasia Cerulea Dolens.