Concomitant Acquired Hemophilia A and Acquired Von Willebrand Syndrome from Distinctive Autoantibodies: Case Report

<b>Background and Clinical Significance:</b> Acquired hemophilia A (AHA) and acquired von Willebrand syndrome (AVWS) are rare bleeding disorders that do not often present concurrently. Here, we report a coexisting AHA and AVWS case due to underlying autoantibodies to factor VIII (FVIII) and von Willebrand factor (VWF). <b>Case Presentation:</b> A patient with gastrointestinal bleeding and prolonged aPTT was diagnosed with AHA and AVWS. The patient was started on immunosuppression with prednisone, cyclophosphamide, and intravenous immunoglobulin, alongside recombinant porcine FVIII replacement, susoctocog alfa. AVWS reduced the half-life of susoctocog alfa, requiring more frequent dosing and laboratory monitoring until AVWS resolved. The patient had two further relapses; the most recent was treated with Rituximab, following which remission has been maintained. <b>Conclusions:</b> Given the potential therapeutic implications, VWF testing should be considered as part of the diagnostic workup for AHA.