We report a case of primary pericardial malignant mesothelioma in a 53-year old male with no asbestos previous exposure. The first clinical sign was a massive pericardial effusion causing hemodynamic disturbances. CT confirmed the initial ecochardiographic diagnosis. The patient underwent pericardiocentesis which improved his hemodynamic status as well as showed malignant cellularity in the liquid examination. Surgical treatment, including pericardiectomy and tumor resection, together with chemotherapy restored normal hemodynamics, the patient being now asymptomatic. We want to emphasize the rarity of this tumor and its insidious clinical presentation even leading to hemodynamic impairment, as well as the great value of echocardiography and CT in its diagnosis, although, in some cases, thoracotomy has been the only valid diagnostic procedure.