May Be Caused by

 Common

Breast cancer metastasis

Bronchogenic carcinoma

Esophageal carcinoma

Fibrosarcoma

Hemangiosarcoma

Leukemia metastasis

Liposarcoma

Lung cancer metastasis

Lymphoma

Lymphoma metastasis

Melanoma metastasis

Myxoma

Myxosarcoma

Pericardial cyst

Rhabdomyoma

Rhabdomyosarcoma

Thymoma

Undifferentiated sarcoma

 Uncommon

Bronchogenic cyst

Fibroma

Hemangioma

Hydatid cyst

Lipoma

Lymphangioma

Mesenchymoma

Mesothelioma

Pericardial diverticulum

Pheochromocytoma

Teratoma