[Recurrent venous thromboses in hypoplasia of the vena cava inferior and factor XII deficiency].

The cause of recurrent pelvic and leg venous thromboses in a 24-year-old man was found to be a combination of two rare anomalies, hypoplasia of the hepatic, prerenal segment of the inferior vena cava and factor XII deficiency (factor XII activity 38%, its antigen 39% of normal), the latter considered a risk factor for thromboembolism. Subsequent fibrinolysis was not successful. No thromboembolic phenomena occurred during the following 16 months of oral anticoagulation with phenprocoumon. When this treatment was discontinued at the patient's behest, there was a recurrence on the contralateral side. Anticoagulation was resumed and has continued now for 1 1/2 years without recurrence. The patient has been largely free of symptoms. Permanent anticoagulation thus seems unavoidable in this case.