Chylopericardium presenting as cardiac tamponade secondary to an anterior mediastinal cystic teratoma.

Cardiac tamponade, the accumulation of fluid in the pericardial space, leads to impaired venous return, loss of left ventricular preload, and hemodynamic collapse. The many causes of tamponade include malignancy, infection, inflammation, connective tissue disorders, and uremia. Herein, we report the case of a young woman who presented with syncope. She was found to have cardiac tamponade secondary to a chylous pericardial effusion that was due to a mature and benign anterior mediastinal cystic teratoma. Numerous reports have described pericardial effusions secondary to an anterior mediastinal cystic teratoma; however, to our knowledge, this is the 1st case of a teratoma causing chylopericardium that presented as tamponade.