Loculated pericardial effusion due to congestive heart failure: an unusual case of vanishing tumor--a case report.

Loculation of a pleural effusion within an interlobar fissure as a result of congestive heart failure is a well-known entity. It has been termed "vanishing" or "phantom" tumor because its roentgenographic appearance simulates a pulmonary tumor and resolves with treatment of the congestive heart failure. The authors describe an 89-year-old man with a loculated pericardial effusion on the left cardiac border on chest roentgenogram. This was initially thought to represent an occult metastatic malignancy; however, its etiology became obvious when it disappeared with therapy of heart failure. Loculated pericardial effusion should be included in the differential diagnosis of roentgenographic densities in the chest when seen on the left cardiac border.