[Diagnosis of mild hemophilia A made by massive intraabdominal bleeding in a 13-year-old boy].

We report a 13-year-old boy who had massive intra-abdominal bleeding without a history of bleeding episodes or traumatic cause of bleeding. The patient underwent surgical treatment because bleeding was not controlled after treatment with tranexamic acid and transfusions including fresh-frozen plasma. Bleeding was traced to the lower left lobe of the liver. The mother's side of the family had a history of bleeding episodes in the boy's grandfather, great uncle, and son of a great aunt. A low level of plasma factor VIII coagulant activity (22%) led to a diagnosis of mild hemophilia A. Compared with severe hemophilia, mild hemophilia is more difficult to diagnose because bleeding episodes are less frequent. Most cases are found after incidental trauma or uncontrolled surgery-related bleeding, there is rarely a family history of hemophilia and activated partial thromboplastin time is normal or slightly prolonged. However, bleeding episodes in mild hemophilia may result in excessive, sometimes life-threatening hemorrhage and require early diagnosis and replacement treatment with adequate amounts of factor VIII, as in severe hemophilia.