Primary pulmonary hypertension is characterized by elevation of pulmonary arterial pressure over 25 mm Hg with increasing of pulmonary vascular resistance. Primary pulmonary hypertension is the result of idiopathic narrowing of pulmonary arteries and extensive remodeling of the pulmonary vasculature in case of lack of the pulmonary interstitial disease, cardiac diseases, and pulmonary thromboembolism. The morphological study revealed the histological vascular elements characteristic in arterial hypertension (intimal proliferation, medial hypertrophy, plexiform and dilatative lesions) associated with recent and organized arterial thrombosis secondary to intimal lesions through a recent infectious process. Our study revealed the necessity of morphological diagnosis in the view of accurate diagnosis and adequate cure. After all, the prognosis of primary pulmonary hypertension remain poor.