Heart Base Tumors are most frequently chemodectomas, which are benign, slow growing tumors of the aortic body chemoreceptors.  

These tumors can cause the accumulation of fluid within the pericardial sac (pericardial effusion), which can eventually be enough to cause cardiac tamponade (collapse of the chambers of the heart).  

This condition is typically best managed by surgical removal of the pericardium (pericardial window or subtotal pericardectomy) as the rate of fluid accumulation is typically very slow.  

These tumors are poorly responsive to chemotherapy and radiation given their very slow growth patterns.  

Recheck echocardiograms are warranted to monitor for any changes that may suggest a different tumor type, such as a carcinoma.