Chylous effusion is a rare but severe complication of Behçet’s disease (BD). Its clinical characteristics and optimal management remain unclear. This study analyzed the clinical features, diagnostic findings, and therapeutic outcomes in patients with BD and chylous effusion.

 In this single-center retrospective study, six patients with BD and chylous effusion between May 2004 and April 2024 were included. Demographic, clinical, imaging, treatment, and follow-up outcome data were systematically collected and analyzed.

The cohort included five males and one female (median age: 30.5 years, range: 19–60). All patients had recurrent oral ulcers; three had genital ulcers, two had uveitis, and two had erythema nodosum. Chylous effusions included chylothorax (n = 6), chylous ascites (n = 1), and chylopericardium (n = 1). All six patients had superior vena cava thrombosis, three had lower extremity deep vein thrombosis, and one had Budd-Chiari syndrome (BCS). Lymphoscintigraphy and magnetic resonance thoracic ductography showed thoracic duct obstruction or impaired lymphatic drainage in all cases. Treatment comprised glucocorticoids with immunosuppressants (cyclophosphamide, azathioprine, methotrexate, or thalidomide), anticoagulants (warfarin or rivaroxaban), therapeutic drainage with a low-fat/medium-chain triglyceride diet, and balloon angioplasty in one case. After a median follow-up of 5 years (range, 2–8), all patients achieved sustained remission without recurrence.

Chylous effusion in BD is frequently associated with major venous thrombosis and thoracic duct dysfunction, suggesting a role for vasculitis, thrombosis, and lymphatic obstruction. A multidisciplinary approach that integrates immunosuppression, anticoagulation, and timely intervention is crucial and may achieve sustained remission without recurrence.

· Chylous effusion in Behçet’s disease is strongly associated with superior vena cava thrombosis, supporting a “vasculitis–thrombosis–lymphatic obstruction” pathogenic mechanism.

· Comprehensive lymphatic imaging with lymphoscintigraphy and MR thoracic ductography is essential for the accurate diagnosis and localization of lymphatic obstruction.

· Multidisciplinary management integrating immunosuppression, anticoagulation, dietary modification, and timely interventions achieved sustained long-term remission with no recurrence during a median follow-up period of 5 years.