Rare interstitial lung disease: Pulmonary Langerhans Cell Histiocytosis in a young non smoking Indian female.

Adult Pulmonary Langerhans Cell Histiocytosis (PLCH) is a rare interstitial lung disease which occurs almost exclusively in smokers. A marked male predominance was initially reported, but recent studies show both men and women are equally affected due to the increasing smoking habits in women. The natural history is variable with 25% of patients having asymptomatic disease while 10-20% progress rapidly to respiratory insufficiency and death. The diagnosis is not easily recognized by clinicians or pathologists. Awareness of the clinical presentation and classical HRCT findings helps in early diagnosis and management of this disease. We report a rare case of severe PLCH in a young non smoking female with a short history who progressed rapidly to respiratory failure and died.