[A rare case of primary Sjögren's syndrome complicated by secondary lymphoid interstitial pneumonia].

A 61-year-old woman was referred to our hospital because of an abnormal chest X-ray shadow. She was diagnosed as having primary Sjögren's syndrome based on sicca syndrome, polyclonal hyper-gamma-globulinemia, and positive results for anti-Ro/SS-A and anti-La/SS-B antibodies. Her chest CT scan revealed bilateral ground-glass shadows and septal thickning in the lower lung field (Fig. 2a). Biopsy specimens obtained by video-assisted thoracoscopy (VATS) showed a dense interstitial lymphoid infiltrate, including lymphocytes and plasma cells, predominantly in the alveolar septae (Fig. 3, a-c). Malignant lymphoma was excluded on the basis of immunohistopathological studies (Fig. 4). A diagnosis of lymphoid interstitial pneumonia was made according to the 2002 American Thoracic Society/European Respiratory Society international multidisciplinary consensus classification (International Classification). After administration of prednisolone and azathioprin, the ground-glass shadows on the chest CT rapidly improved (Fig. 2b). The clinico-radiologic-pathologic diagnosis based on the VATS procedure and the International Classification is appropriate and effective for treating collagen vascular disease-associated interstitial lung disease.