[Primary pulmonary hypertension]

Primary pulmonary hypertension is a rare and poor prognostic disease. This disease has a pulmonary arteriopathy that is due to unknown cause. Histological study shows medial hypertrophy and fibrosis. Plexogenic arteriopathy is usually observed, but not always. Recently gene mutation was discovered in familial primary pulmonary hypertension. Differential diagnosis is very important because therapies are much different among pulmonary hypertensions due to other causes. In the near future, the mechanism of the disease will be apparent, and therapy must be improved.