Pulmonary hypertension (PHT) is an emerging issue. The prognosis in PHT is usually poor, independently from the etiology, with progressive right ventricle failure. Despite right Heart Catheterism is the gold standard for diagnosis of PHT, echocardiography provides important information about prognosis and is helpful in both follow-up and first evaluation of PHT patients, showing a good correlation with invasively measured parameters by right heart catheterization. However, it is important to understand the limits of this method, particularly in some settings, where transthoracic echocardiography has shown a lack of accuracy. In this case report we documented a case of rapid onset (3 months) idiopathic PHT and we provided a critical analysis of echocardiographic role in PHT.