Thrombotic thrombocytopenic purpura without any evidence of thrombotic lesions at autopsy

Diagnosis of thrombotic thrombocytopenic purpura (TTP) is usually based upon the clinical features, and does not always involve histopathological evidence. We recently had experience with a patient who developed the five signs characteristic for TTP. He had been treated for liver cirrhosis associated with chronic hepatitis B infection, and the hepatic function was severely impaired at admission. Blood levels of vWF (von Willebrand factor) and factor VIII were highly elevated to 506% and 632%, respectively. These findings suggested severe endothelial damage. Thus, the patient was diagnosed as having TTP secondary to severe hepatic damage, and plasma exchanges were initiated immediately. He responded poorly to the treatment, and finally died of pulmonary hemorrhage. At autopsy, hepatocellular carcinoma was identified in the cirrhotic liver, but it was surprising that thorough postmortem examination failed to show any evidence of thrombotic lesions. Our experience suggests that secondary TTP does not always involve pathological evidence of the thrombotic lesions, and that the formation of thrombi causing vessel occlusion might not be essential in the pathogenesis of some secondary TTP.