en Pathology Pathology case report case report Primary malignant neoplasms of the pericardium are rare and are predominantly mesotheliomas, followed by benign localized fibrous mesothelioma, malignant fibrosarcoma, angiosarcoma and benign and malignant teratomas. 1 This article concerns an atypical presentation of this malignant tumor with symptoms and signs of pericardial effusion. This unusual feature was complete encasement of the heart by this tumor, without pericardial effusion. Pericardium, tumor 163 167 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-385&slc_lang=en&sid=1 MOHAMMAD REZA MOTAMEDI 20031947532846005196 20031947532846005196 Yes From the Departments of Cardiology Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran P SHISHINEH 20031947532846005197 20031947532846005197 No From the Departments of Pathology, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran.