CT evaluation of distended pericardial recess presenting as a mediastinal mass.

A patient with a remarkably distended pericardial recess due to massive pericardial effusion mimicking a mediastinal mass is reported. The nature of the "mass lesion" was clearly demonstrated by CT and the lesion disappeared after removal of the pericardial effusions. The importance and usefulness of CT in evaluation of pericardial recesses is stressed.