Massive hemoptysis as the initial presentation of Behçet disease complicated by multisite thromboembolism: A case report

RATIONALE: Behçet disease (BD) is a systemic vasculitis with highly variable presentations. While vascular involvement is a major complication and a leading cause of mortality, the pattern can vary dramatically. This report details a severe and rare manifestation dominated by extensive thrombotic events. PATIENT CONCERNS: A 20-year-old male with a history of recurrent oral ulcers presented with massive hemoptysis and a persistent fever of 39°C. Laboratory findings revealed severe anemia and a positive pathergy test. DIAGNOSES: Imaging revealed extensive thrombosis involving the inferior vena cava, right atrium, multiple pulmonary veins, and an intracardiac thrombus in the right ventricle. The patient met the International Criteria for Behçet's Disease criteria with 4 points, confirming a diagnosis of BD complicated by severe multisite thromboembolism. INTERVENTIONS: The patient was managed using a carefully timed, sequential approach. Treatment included initial measures for immediate hemostasis, followed by aggressive immunosuppression with high-dose corticosteroids, and subsequent tailored anticoagulation and biological immunotherapy. OUTCOMES: The therapeutic approach resulted in significant clinical and radiological improvement, successfully resolving the life-threatening thrombi without inducing recurrent hemorrhage. LESSONS: BD can manifest with an aggressive, purely thrombotic phenotype involving multisite venous and intracardiac structures without classic arterial aneurysms. In cases presenting with concurrent massive hemoptysis, a sequential strategy - prioritizing immediate hemostasis before aggressive immunosuppression and cautious anticoagulation - is crucial for safe and effective management.