A right atrial/auricular mass is most likely a hemangiosarcoma.  

Other tumor types would include chemodectoma or carcinoma.  

The prognosis is typically poor; however, with chemotherapy and surgery (pericardectomy or pericardial window), these patients can typically have a high quality of life.

Their overall life expectancy is unfortunately short (typically 90-120 days).  Consultation with an oncologist is highly recommended to discuss potential treatment strategies and the associated survival times and quality of life with each potential chemotherapeutic option