Primary Sjögren's syndrome accompanied by pleural effusion: a case report and literature review.

Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by the infiltration of lymphocytes in exocrine glands, specifically the salivary and lacrimal glands, resulting in the typical symptoms of xerophthalmia and xerostomia. SS may be accompanied by pleural effusion when the lung is involved, but this occurrence has been reported in only 10 cases in the literature. We report the case of a 42 year-old woman with severe bilateral pleural effusion for eight years. Primary Sjögren's Syndrome was finally diagnosed based on the presence of xerophthalmia and xerostomia, biopsy of the minor salivary glands, and positive anti-SS-A antibody in the serum and pleural effusion. Biopsy of the parietal pleura through video-assisted thoracoscopy revealed infiltration of lymphocytes. The patient had a long history of pleural effusion without clear etiology. Malignant disease was first suspected because of abnormal density lesion on the left lung and malignant cells found on cytology, but PET-CT revealed no malignant lesion. Examinations did not support infection, malignant tumor, pulmonary sarcoidosis, or other connective tissue diseases. This data could be useful for the future study of pleural effusion in SS.