• 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 anitibody 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.
(Arch Intern Med. 1990;150:1113-1115)