Acquired Hemophilia A (AHA) Associated With Malignancy and Antiphospholipid Antibodies: Two Case Reports With Distinct Etiologies

Acquired hemophilia A (AHA) is a rare but potentially life-threatening autoimmune bleeding disorder caused by autoantibodies against factor VIII (FVIII). It is commonly associated with underlying conditions such as malignancy, autoimmune diseases, and infections. We report two cases of AHA with distinct etiologies, highlighting diagnostic and therapeutic challenges. The first case involves a 70-year-old man with inoperable periampullary carcinoma who presented with spontaneous, extensive bruising and anemia. Laboratory evaluation revealed AHA with the presence of FVIII inhibitor. He was managed with bypassing agents and corticosteroids, resulting in normalization of coagulation parameters. The second case describes a 69-year-old man with antiphospholipid antibodies and a recent viral illness, presenting with neurological symptoms suggestive of Miller Fisher syndrome and bleeding manifestations. Investigations confirmed AHA with FVIII inhibitors. He was treated with recombinant factor VII, corticosteroids, and cyclophosphamide, achieving clinical and laboratory improvement. These cases illustrate the heterogeneous etiologies and complex pathophysiology of AHA, including malignancy-associated, autoimmune, and infection-related mechanisms. Early recognition of unexplained bleeding with isolated prolonged activated partial thromboplastin time (aPTT) is essential for timely diagnosis. Management requires a dual approach that targets bleeding control and inhibitor eradication, along with treatment of underlying conditions. Awareness of overlapping disorders, particularly in patients with antiphospholipid antibodies, is important for guiding appropriate management and improving outcomes.