BackgroundThe simultaneous diagnosis of severe aortic regurgitation and aortic root pseudoaneurysm resulting from traffic injury is extremely rare. This report presents the case of a patient with Marfan syndrome who experienced aortic root pseudoaneurysm and subacute severe aortic regurgitation following a traffic accident.Case presentationA 64-year-old woman was diagnosed with Marfan syndrome 16 years ago and is undergoing ongoing follow-up at an outpatient clinic. Eight years previously, the patient underwent total arch replacement combined with J-graft open stent graft® (JGOS; Japan Lifeline Co., Tokyo, Japan) deployment for acute type A dissection. Five months before presentation, the patient suffered a left rib fracture in a traffic accident and received conservative management at a local hospital. The patient presented to the emergency room with worsening shortness of breath and orthopnea. Echocardiography revealed severe aortic regurgitation and moderate tricuspid regurgitation. Computed tomography revealed new-onset pseudoaneurysm at the aortic root. Surgical repair was successfully performed using a modified Bentall procedure with a bioprosthetic valve and tricuspid annuloplasty. Intraoperative findings revealed pseudoaneurysm with perforation of the right sinus of Valsalva. Although the left and right aortic valve leaflets were normal, the noncoronary leaflet exhibited a ruptured fibrous strand of a cusp fenestration, resulting in acute aortic regurgitation.ConclusionsThis case report highlights the rare occurrence of aortic root pseudoaneurysm and subacute aortic regurgitation following a traffic accident. In cases of blunt chest trauma, particularly in patients with Marfan syndrome, frequent examination is crucial to assess the possibility of posttraumatic aortic regurgitation and aortic injury.