LAUSR

Pulmonary thromboembolism (PTE) is rarely reported in Behçet's disease (BD) due to its distinctive thrombus‐forming mechanism. In BD, the inflammation on vessel walls causes venous thrombosis. The thrombi are considered to be tethered to the inflamed walls making embolization less frequent. Thus, immunosuppressive agents are the mainstay of treatment. However, the necessity of anticoagulation therapy is controversial because of its uncertain efficacy of resolving thrombi and the possibility of fatal side effects of hemorrhage. A 25‐year‐old man with recurrent oral aphthae visited with abrupt onset of dyspnea and chest pain. Based on history, imaging studies and laboratory results, he was diagnosed with BD with vascular involvement and antiphospholipid syndrome (APS), causing PTE from deep vein thrombosis. The co‐existing APS may have further promoted the thrombosis, shifting his blood profile toward the hypercoagulable state. Immunosuppressive therapy with glucocorticoid and azathioprine, and concomitant anticoagulation with warfarin were achieved successfully without any fatal complications. When atypical features of vascular involvement in BD develop, other coexisting diseases should be considered to design an optimal therapeutic plan.