Subdural hematoma in a patient with Hageman trait--case report. 
A 61-year-old man with severe factor XII deficiency presented with a subdural hematoma appearing as mixed but mainly high density by computed tomography in the left frontotemporoparietal region.  No cranial injury was reported in the medical history of the patient.  Clotting system study showed less than 1% functional activity of factor XII, whereas the levels of the other clotting factors were within the normal ranges.  Partially clotted and hemolyzed subdural hematoma was removed through a craniotomy.  The postoperative course was uneventful.  The patient later died of severe circulatory-respiratory failure.  We believe that the subdural hematoma may have developed as a result of a minor head trauma sustained in the past.  We suggest that impairment of fibrinolytic activation related to severe factor XII deficiency might have contributed to the delay of dissolution of the subdural hematoma which, under ordinary circumstances, would have formed chronic subdural hematoma.