[Pulmonary Langerhans cell histiocytosis in a non-smoking Japanese woman].

A 44-year-old Japanese woman was admitted to our hospital because of dry cough and dyspnea on exertion. She had never smoked. She had been passively exposed to smoking by her husband and co-workers from the age of 21 (1984) to 33 (1996). She had previously developed pneumothorax twice, in 1985. On admission, computed tomography (CT) of the chest showed reticulonodular opacities predominant in bilateral upper lung fields, and pulmonary function tests revealed a decrease in vital capacity. The differential diagnoses were sarcoidosis, idiopathic pulmonary fibrosis and pulmonary Langerhans cell histiocytosis (PLCH). Video-assisted thoracic surgery was performed to make a definitive diagnosis. A histological specimen revealed the presence of CD1a-positive Langerhans cells in bronchiolocentric nodular lesions, leading to a diagnosis of PLCH. She was given 0.5 mg/kg bodyweight/ day oral prednisolone. Her symptoms disappeared with steroid maintenance therapy, and her vital capacity on pulmonary function testing was prevented from further deterioration. Based on the pathogenesis of PLCH, this case suggested that not only active smoking, but also passive smoking, played an important role in the development of PLCH.