Bilateral Pleural Effusion Associated with Miliary Sarcoidosis

摘要

Sarcoidosis does not commonly cause pleural effusion (1-10%), and the bilateral form is extremely rare. An afebrile 69-year-old man complained of dyspnea for 2 weeks. Chest computed tomography revealed bilateral pleural effusion without significant mediastinal lymphadenopathy (Figure 1). Upper-predominant micro-nodules on lung parenchyma and pleura were also found. Echocardiography and ophthalmological examination detected no abnormal findings. Pleural effusion was exudative and lymphocytic with high aden-osine deaminase activity (right, 46.7 U/L; left, 42.6 U/L). Although the serum level of angiotensin-converting enzyme was not elevated, that of lysozyme (34.7 μg/ ml), 1,25-dihydroxyvitamin D (174 pg/ml), and calcium (11.9 mg/dl) was increased. The result of IFN-γ release assay test was negative. Bronchoalveolar lavage fluid (BALF) analysis showed an increase of lymphocyte subsets (26%), but the CD4/ CD8 ratio was not elevated (1.98). Trans-bronchial lung biopsy did not provide any specific findings. On thoracoscopy, profuse white nodules were observed on the right visceral and parietal pleura (Figure 2). Biopsy demonstrated several epithelioid cell granulomas without Ziehl-Neelsen-, periodic acid-Schiff-, or Grocott-positive organisms or malignant findings (Figure 3, hematoxylin-eosin staining). Thus, we diagnosed him as having sarcoidosis. After a month of prednisolone administration (0.5 mg/kg), the bilateral pleural effusion almost disappeared and micronodules markedly decreased (Figure 4). All cultures on effusion, BALF, and biopsy specimens were negative for acid-fast bacilli and fungi. This case report indicates that, even in patients with bilateral pleural effusion, pleural involvement of sarcoidosis should be included in the differential diagnosis, especially in those having widespread lung parenchymal lesions suggestive of pulmonary sarcoidosis. The diagnosis is occasionally challenging as in our case, and detailed pathological and microbiological examinations using thoracoscopy are essential for excluding other diseases, such as tuberculosis and malignant pleurisy. Corticosteroid therapy is recommended for symptomatic patients, and the response is usually favorable, but self-limited or recurrent cases have been also reported.