42 year old woman with irregular hypodense polypoid mass arising in left atrium, with encasement and near occlusion of left pulmonary vein and Circumferential encasement of left circumflex artery with tumor infiltration of the pericardium

“Primary cardiac tumours are very rare with a prevalence rate ranging from 0.001 to 0.03% in autopsy series. Most primary cardiac tumours are benign, such as myxoma, lipoma, papillary fibroelastoma and rhabdomyoma. Angiosarcomas and myxofibrosarcomas are the most common sarcomas of the heart. However, a primary cardiac chondroblastic osteosarcoma in the heart is a unique case, due to the fact that this type is considered to be a member of the extraskeletal osteosarcoma (ESOS) family.”
Extraskeletal chondroblastic osteosarcoma in the left atrium 
Özge Korkmaza et al.
Interactive CardioVascular and Thoracic Surgery 19 (2014) 1077–1079

“ESOS is an uncommon malignant neoplasm, which can produce osteoid, bone or chondroid matrix, located in the soft tissue without connection to the skeleton. The most common location is the lower extremity, especially the thigh, followed by the upper extremity and the retroperitoneum.”
Extraskeletal chondroblastic osteosarcoma in the left atrium 
Özge Korkmaza et al.
Interactive CardioVascular and Thoracic Surgery 19 (2014) 1077–1079

” Primary cardiac lymphoma (PCL) is a rare extranodal lymphoma accounting for 1% to 1.5% of all primary cardiac tumors, with the majority involving the right heart. PCLs are aggressive and are usually of the non-Hodgkin type. A typical patient is an immunocompetent male adult (2:1 male to fe- male ratio) in his 6th to 7th decade of life. The mean age is 60 years with a range of 12 to 86 years.44 Certain subtypes occur more commonly in the immunocompromised. Post- transplant lymphoproliferative disorder, a B-cell proliferation related to Epstein-Barr virus infection, may develop mostly in lung and cardiac transplant recipients. Primary effusion lymphoma (PEL) uniquely affects patients with human immunodeficiency virus, which is associated with human herpesvirus-8 (HHV-8)/Kaposi sarcoma– associated herpesvirus.”
Cardiac Neoplasms Radiologic-Pathologic Correlation 
John P. Lichtenberger III et al.
Radiol Clin N Am 59 (2021) 231–242

“PCL commonly presents as a homogenously low- attenuating, hypoenhancing mass on contrast- enhanced CT, involving the right atrium or right ventricle in 92% of cases. Necrosis and involvement of the cardiac valves are atypical and, if pre- sent, should invoke an alternative diagnosis such as angiosarcoma. Extension along the epicardial surface with encasement of the coronary arteries, aortic root, and great vessels is classic. There is often pericardial thickening and massive pericardial effusion, which can occasionally be the only imaging manifestation, particularly in the PEL subtype.”
Cardiac Neoplasms Radiologic-Pathologic Correlation 
John P. Lichtenberger III et al.
Radiol Clin N Am 59 (2021) 231–242