Abstract
A case of primary pulmonary hypertension due to diffuse pulmonary arterioral thrombosis is reported of which the diagnosis was not affirmed before death but only after autopsy. The clinical symptoms and signs, laboratory findings, macroscopic and histopathological findings were compared with those of previous reports. Thus the reason why the diagnosis was so difficult to decide before death was made clear. The authors also reported that primary pulmonary hypertension and fibrosis were able to be differentiated from congestive heart failure by means of pulmonary function test after regitine administration.
