[A case of primary Sjögren's syndrome complicated with lung adenocarcinoma].

A 69-year-old woman presented with headache. Her chest radiograph and computed tomographic scans showed a mass shadow causing superior vena cava syndrome. Bronchofiberscopic examination was nonproductive. The serum value of carcinoembryonic antigen was highly elevated, so we made a presumed diagnosis of primary non-small lung cancer. She also complained of dry eyes and mouth. The elevated values of serum antibodies against SS-A and SS-B and further examinations resulted in a definitive diagnosis of primary Sjögren's syndrome. Chemotherapy was not effective and she died 14 months later. Autopsy revealed that the mass shadow was a primary lung adenocarcinoma. At the age of 66 she suffered a refractory pneumothorax and her pulmonary cysts or bullae were surgically resected. Those lesions had bullae, emphysema, and alveolar septae thickened by infiltration of lymphoplasmacytic cells. Because she had complained of xerostomia for the last few decades, we associated the cysts with Sjögren's syndrome. Thoracic CT scans at that time showed a nodule next to a cystic lesion. We raise a possibility that lung cancer might derive from cystic lesions associated with Sjögren's syndrome.