Evaluation of Chylothorax and Chylous Ascites

There are numerous causes of chylothorax, the most common being cancer and trauma. Subclavian vein cannulation, with or without thrombosis, is another well-described cause, occurring more commonly in neonatology and pediatrics. The patient described in this case report presented with chylothorax and chylous ascites secondary to idiopathic subclavian vein thrombosis. Two years later, he was diagnosed with advanced hepatocellular carcinoma. He denied trauma, venous cannulation, or surgery involving the shoulder. Physical examination revealed no evidence for deep venous thrombosis; there was no venous engorgement, swelling, or pain. Dedicated imaging of the left subclavian vein, either by computed tomography or Doppler ultrasound, should be considered when evaluating patients with chylothorax or chylous ascites. Patients presenting with idiopathic thrombosis should undergo hypercoagulability workup and are at high risk for occult malignancy.