A 68-year-old woman was admitted with a chief complaint of bilateral lower chest pain. Computed tomography showed bilateral pleural effusion and left axillary lymphadenopathy, with high pleural effusion adenosine deaminase (ADA), mildly elevated serum soluble IL-2 receptor, and high serum IgG4 levels. Interferon-gamma release assay was negative. She underwent pleural fluid analysis and bronchoscopy, but neither malignant lymphoma nor IgG4-related respiratory disease was diagnosed. The pleural effusion acid-fast bacillus liquid culture test collected on the 8th day was positive on the 43rd day, and Mycobacterium tuberculosis was identified by polymerase chain reaction test. Treatment with an anti-tuberculosis drug was initiated.
The detection rate of M. tuberculosis in pleural effusion is low, and the diagnosis of tuberculous pleurisy is often difficult. The levels of adenosine deaminase, which may be a marker in tuberculous pleural inflammation, can also be high in malignant lymphoma, rheumatoid arthritis, cancer, and IgG4-related diseases. In addition, there are reports of cases showing high soluble IL-2 receptor levels in tuberculosis that suggest that they may be involved in IgG4-related diseases.
In order to avoid delay in the diagnosis of tuberculous pleurisy, it is imperative to distinguish it from malignant lymphoma and IgG4-related respiratory disease.