Background:Hughes-Stovin Syndrome (HSS) is a rare potentially fatal vasculitis supposedly belonging to the spectrum of Behçet disease without ocular involvement. HSS tends to play by a temporal pattern, starting with thrombosis and followed by formation of pulmonary aneurysms. Since its mortality can reach 25% of cases, the early recognition and the appropriate therapy represent the major challenges.Objectives:In this report, we aimed at describing a rare case of HSS successfully treated in accordance with a prompt combined management with endovascular approach and immunosuppressive treatments.Methods:We described a Caucasian 33-year-old man presented to the Emergency Room of our Hospital with hemoptysis associated with dyspnea and chest pain, without fever and hypotension, with a 2-year history of painful genital and oral ulcers. Blood test revealed anemia, elevated white cell count with increased C-reactive protein (77 mg/L) and D-dimer (2740 ng/mL). Doppler ultrasonography of legs showed thrombosis of the left femoral vein, while CT-angiography reported multiple aneurysms of the pulmonary arteries. An early and extensive work-up for infections and autoimmunity did not document relevant abnormalities. An appropriate genetic assessment revealed the HLA-B51 positivity. The patient immediately underwent endovascular embolization with coils and plugs of the largest pulmonary aneurysm, and inferior vena cava filter placement. Then, he started methylprednisolone (1 mg/kg/day) IV for three days in association with LMWH (6000 IU/day). Prednisone (1 mg/kg/day) in combination with cyclophosphamide (100 mg daily) were started orally, with tapering of steroids within a month. At the tight follow up (1 month and 3 months later), no genital and oral ulcers nor vascular thrombosis occurred, and acute phase reactants were in normal range. The 3-month-CT angiography showed a complete resolution of the aneurysms and no new changes.Results:The peculiar diagnosis of HLAB51 positive HSS with multiple pulmonary aneurysms was made. The appropriate imaging followed by a prompt endovascular embolization of aneurysms with LMWH treatment were successfully performed. Interestingly, the oral combination therapy with corticosteroid and cyclophosphamide showed a rapid efficacy with a relevant safety profile. At the tight follow up, the young man improved significantly with clinical signs and pulmonary changes (Figure 1 next page).Conclusion:This case is of interest because of the early recognition of such a rare disease that allowed an adequate combined radiological, vascular, and rheumatologic approach. In our case, LMWH resulted useful in preventing the pulmonary embolism, despite the use of anticoagulants is still debated in HSS. Moreover, the endovascular embolization let a less invasive approach to surgery without the need for multiple surgical procedures. For the first time, we documented that oral cyclophosphamide showed an early efficacy as a first line therapy of a HLA-B51 HSS.