Antinuclear antibody in pericardial fluid from a patient with primary cardiac lymphoma

Pericarditis may be the initial manifestation of systemic lupus erythematosus. Although it is known that antinuclear antibody can be detected in the serum of patients with a wide variety of diseases, it has been proposed that the detection of antinuclear antibody in serosal fluid is a sensitive and specific test for determining that effusions are due to systemic lupus erythematosus. A case is presented in which antinuclear antibody in high titer was identified in the pericardial fluid of a patient who was found at autopsy to have a primary cardiac lymphoma. The case indicates that antinuclear antibody detected in serosal effusions should not be considered pathognomonic for systemic lupus erythematosus.