Spotlight on Respiratory Pathophysiology Dyspnea and reduced exercise capacity with normal lung function marking onset of pulmonary Langerhans' cell histiocytosis

Pulmonary Langerhans' cell histiocytosis is an uncommon cystic-granulomatous lung disease of unknown etiopathogenesis affecting adult smokers. It is probably caused by an uncontrolled immune response to exogenous antigens and sustained by Langerhans' cells, T lymphocytes and many cytokines. In adults, pulmonary involvement generally occurs as a localized disease characterized by the formation of granulomatous lesions in distal bronchioles which may revert or progress to cystic disease. The diagnosis is usually based on clinical and radiological aspects; there is no consensus in the literature on the need or not to obtain biopsy. In this paper we describe a case of pulmonary Langerhans' cell histiocytosis diagnosed through a combination of imaging, functional and cytohistological data obtained by endoscopic techniques.