Presentation of an acquired factor VIII inhibitor with a muscular haematoma mimicking a deep venous thrombosis in a patient with breast cancer.

: Acquired haemophilia is a rare disorder that it is associated with several diseases. Patients may present with spontaneous haematomas in different places which can sometimes be fatal. We present a 69-year-old woman with breast carcinoma who developed a factor VIII inhibitor. The initial haemorrhagic event was a spontaneous deep muscular haematoma in the right leg mimicking a deep venous thrombosis. She was successfully treated with prednisone.