Life-threatening acute heart failure due to primary cardiac undifferentiated pleomorphic sarcoma.

A 41-year-old man was admitted with acute heart failure and shock status. An echocardiogram showed a mobile tumor obstructing blood flow through the mitral valve with a stalk on the posterior left atrium (LA) wall. Emergent open-heart surgery was performed to resect the tumor (77×36×30 mm). Histological examination confirmed that it was an undifferentiated pleomorphic sarcoma. Unfortunately, positron emission tomography performed five months after surgery demonstrated a local recurrence around the right pulmonary vein and LA. We performed proton beam radiotherapy to treat the local recurrence, and it was effective. The patient has survived more than one year since the first life-threatening heart failure episode.