CO11 | Acquired haemophilia A and bullous pemphigoid as a paraneoplastic manifestation of low-grade urothelial carcinoma: a case report

Premises: Acquired haemophilia A is a rare disease resulting from autoantibodies against endogenous factor VIII. Bullous pemphigoid is an autoimmune bullous disease. Both diseases may present a manifestation of cancer.Description of the Case report: A 63-year-old male patient diagnosed with bullous pemphigoid was started on oral methylpredisone. Few weeks later, the patient presented to the emergency department for gastrocnemius intramuscular haematoma. Blood tests showed severe anaemia and prolonged activated partial thromboplastin time (aPTT). Mixing test was performed, with no aPTT correction. Factor VIII was undetectable, with presence of high level of inhibitors at Bethesda assay. Suspecting a paraneoplastic syndrome, a computed tomography was performed which showed a bladder polyp. High-dose oral prednisone (1 mg/kg) was started and polyp resection was postponed due to high bleeding risk. Later on, the patient presented also deltoid intramuscular haematoma, so recombinant factor VIII and immunosuppressive therapy with rituximab were started. Six months later, factor VIII normalized, the patient was able to undergo transurethral bladder resection. Histologic exam showed low-grade urothelial carcinoma.Conclusions: Acquired haemophilia A usually manifests as spontaneous and severe bleeding. Treatment involves control of bleeding source and eradication of the factor VIII inhibitor. Investigation of the underlying condition is mandatory as it may represent the manifestation of a cancer, especially when associated with another paraneoplastic syndrome, such as bullous pemphigoid.