Pulmonary vein thrombosis is a rare disease and is usually represented as a complication of atrial fibrillation,pulmonary tumors,and Iobectomy.Although it is a potentially life threatening condition,the venous disease is easy to misdiagnose because of the non-specific symptoms.In this article,we present a 30-year-old patient who suffered from pulmonary vein thrombosis without any causes.He was diagnosed with other pulmonary disorders till the thrombus within the pulmonary vein extended into the left atrium.Left atrium mass resection and a left lower Iobectomy were undertaken with relative urgency.The postoperative course was uneventful.The patient received a long course of oral anticoagulant therapy.