Case report: cardiac tamponade resembling an acute myocardial infarction as the initial manifestation of metastatic pericardial adenocarcinoma.

Pericardial malignancies are uncommon, usually metastatic, linked to terminal oncology patients, and rarely diagnosed premortem. A very small number of patients will develop signs and symptoms of malignant pericardial effusion as initial clinical manifestation of neoplastic disease. Among these patients, a minority will progress to a life-threatening cardiac tamponade. It is exceedingly rare for a cardiac tamponade to be the unveiling clinical manifestation of an unknown malignancy, either primary or metastatic to pericardium. We present the case of a 50-year-old male who was admitted to the emergency department with an acute myocardial infarction diagnosis that turned out to be a cardiac tamponade of unknown etiology. Further studies revealed a metastatic pericardial adenocarcinoma with secondary cardiac tamponade. We encourage considering malignancies metastatic to pericardium as probable etiology for large pericardial effusions and cardiac tamponade of unknown etiology.