[A morphological study of primary pulmonary hypertension: an analysis of five autopsies].

Five autopsy cases of typical primary pulmonary hypertension are reported. The histopathological features were as follows: marked medial hypertrophy of muscular pulmonary arteries; muscularization of arterioles; intimal fibrosis and fibroelastosis of muscular pulmonary arteries accompanied by a typical onion skin configuration. The plexigenic pathological change is considered to be the result of response, at the late stage, to pulmonary hypertension rather than due to congenital abnormality or embolism.