Retroperitoneal hematoma complicated with colocutaneous fistula in a case of severe hemophilia B

Retroperitoneal hematoma rarely occurs in hemophilia B cases caused by factor IX deficiency. It typically arises as a result of trauma or surgical procedures, though spontaneous cases are rare. We present our patient who developed spontaneous retroperitoneal hematoma and was subsequently complicated by abscess, coloenteric fistula, osteomyelitis and arteria lumbalis bleeding. Surgical intervention was avoided for a long time due to difficulty of hemophilia B management for surgery. Therefore, the complication became severe and life-threatening. The patient was treated with successful and long-lasting surgical interventions, intravenous antibiotics and factor IX replacements. To the best of our knowledge, the case we present is the first hemophilia patient in the literature complicated by colocutaneous fistula.