Approach to cardiac masses: Thinking inside and outside the box

Table 1 Classification of cardiac masses

Site of mass	Normal variant structures	Abnormal masses
Left ventricle	False tendon, trabeculations, papillary muscle	Thrombus, tumor
Left atrium	Coumadin ridge, fibromuscular membrane	Thrombus, tumor
Right ventricle	Moderator band, trabeculations, pacemaker leads	Thrombus, tumor
Right atrium	Crista terminalis, eustachian valve, Chiari network, lipomatous hypertrophy of atrial septum, pacemaker leads	Thrombus, tumor
Valves	Lambl’s excrescence (aortic valve), annular calcification	Thrombus, infective vegetations (native valve and prosthesis), tumor (native valve)
Pericardium	Pericardial fat	Pericardial malignant mesothelioma
Paracardiac	Hiatal hernia	Mediastinal/thoracic tumor compression

Table 2 Simplified World Health Organization classification of heart and pericardial tumors[3]

Group	Histologic type
Benign congenital/childhood	Rhabdomyoma, histiocytoid cardiomyopathy, congenital or childhood fibroma, cystic tumor of the atrioventricular node, hamartomas, germ cell tumors, schwannoma, granular cell tumor
Non-neoplastic tumors of adults	Papillary fibroelastoma, lipomatous hypertrophy of atrial septum
Neoplastic benign tumors	Myxoma, lipoma, hemangioma
Malignant tumors	Angiosarcoma, rhabdomyosarcoma, leiomyosarcoma, osteosarcoma, synovial sarcoma, pericardial malignant mesothelioma, lymphoma
Intermediate behavior	Inflammatory myofibroblastic tumor, low-grade angiosarcoma, infiltrating hemangiomas, cardiac paraganglioma, solitary fibrous tumor of the pericardium, adult cellular rhabdomyoma