Pulmonary Thromboembolism in a Patient With Behçet's Disease: A Case Report.

Behçet's disease (BD) is a rare, chronic, and multisystemic vasculitis characterized by recurrent oral and genital ulcers, uveitis, and skin lesions. Although vascular involvement is common in BD, pulmonary manifestations are rare and potentially fatal. Among these, pulmonary thromboembolism (PTE) represents an exceptional event, as deep vein thrombosis (DVT) in BD usually remains adherent to the vessel wall and seldom embolizes to the lungs. We report a 52-year-old male with BD who presented with a four-day history of progressive dyspnea, productive cough, and new-onset hemoptysis. He had been in clinical remission for one year after discontinuing colchicine therapy. On admission, his oxygen saturation was 90% on room air, with inspiratory crackles on auscultation. Laboratory findings revealed leukocytosis, elevated inflammatory markers, and a markedly increased D-dimer level. CT pulmonary angiography demonstrated multiple filling defects in the right main and segmental pulmonary arteries without evidence of pulmonary artery aneurysm (PAA). Anticoagulation with heparin was initiated. However, during hospitalization, the patient developed oral and genital aphthous ulcers, indicating disease relapse. Immunosuppressive therapy with cyclophosphamide and prednisolone led to significant clinical improvement. This case underscores the importance of maintaining a high index of suspicion for PTE in BD and highlights the necessity of distinguishing BD-related thrombosis from conventional embolic events, as management requires a combination of immunosuppressive and anticoagulant therapy to prevent fatal complications.