[A case of systemic lupus erythematosus associated with Sjögren's syndrome diagnosed by lung localization]

A 30-year-old female, diagnosed as having SLE and followed at our hospital while receiving oral prednisolone (5 mg/day) for about 6 months, was admitted because of fever and productive cough. Chest X-ray and CT scan showed a tumor-like homogeneous shadow in the right middle lobe. Antibiotic treatment was not effective. Specimens obtained by TBLB revealed massive infiltration of mature plasma cells and lymphocytes into the alveolar septa and interstitial tissues. These findings were considered compatible with lymphoid interstitial pneumonia. Associated conditions such as Sjögren's syndrome were suggested, but the diagnostic criteria of Sjögren's syndrome were not satisfied. Both the abnormal shadow on chest X-ray and the clinical symptoms markedly improved by increasing the dose of prednisolone (20 mg/day). After 3 months, however, bilateral BAL findings showed alveolar lymphocytosis, providing evidence that subclinical diffuse pulmonary involvement had continued. This case indicates that radiological appearance may vary depending on the extent of lung involvement, even if the histological features are identical. It is concluded that the present diagnostic criteria of Sjögren's syndrome must be reconsidered so as not to overlook subclinical and asymptomatic cases of Sjögren's syndrome.