Adult heart tumor refers to neoplasms of the heart that manifest in adults and generally present with a variety of non-specific manifestations (depending on tumor site and infiltration) such as weight loss, exhaustion, hemorrhagic pericardial effusion, heart failure, arrhythmias, and embolisms, or that can also be asymptomatic. In adults 75% of heart tumors are benign, with myxoma being the most common benign tumor (accounting for 50-70% of all primary heart tumors) and rhabdomyosarcoma (see this term) comprising 75% of malignant heart tumors. Other malignant tumors of the heart include fibrosarcoma and leiomyosarcoma (see these terms).