Primary malignant pericardial mesothelioma is an exceptionally rare tumor, and making an antemortem diagnosis of this disease is notoriously difficult. We herein report the case of a 61-year-old woman with pericardial mesothelioma who presented with shortness of breath and peripheral edema of the lower limbs. Chest computed tomography (CT) showed an anterior mass and thickened pericardium with multiple pericardial nodules. A biopsy of the mediastinal mass was performed using right thoracotomy, and the histological findings indicated a sarcomatoid tumor. The patient was treated with chemotherapy; however, she but died three months after diagnosis. An autopsy confirmed a final diagnosis of sarcomatoid type primary malignant pericardial mesothelioma following extensive immunohistopathological examinations.