The natural history of adult pulmonary Langerhans cell histiocytosis: a prospective multicentre study
BACKGROUND Pulmonary Langerhans' cell histiocytosis (LCH) is a diffuse, smoking-related lung disease characterised pathologically by proliferation of abnormal Langerhans' cells, cyst formation and vascular abnormalities, and physiologically by a decreased diffusing capacity. The aim of this study was to describe our experience with pulmonary LCH at our institution during the past 30 years, with particular reference to diagnosis and long-term outcome. PATIENTS AND METHODS Seven patients, two men and five women, mean age 33 years (range 26-49 years), who had been evaluated for pulmonary LCH, were retrospectively studied. All available clinical, diagnostic and pathological data were included. RESULTS The patients presented with symptoms of dyspnoea, cough, pleuritic pain, anorexia and fatigue. Chest X-ray and high-resolution computed tomography (HRCT) showed bilateral nodular and cystic lesions, with a predilection for the middle and upper lung zones. In the majority of patients, lung function tests showed a decrease in diffusing capacity. In six patients the diagnosis of pulmonary LCH was made after immunohistochemical examination of an open lung biopsy specimen. In one patient a confident diagnosis was made radiologically. During serial follow-up, median seven years (range 1-28 years), three patients stopped smoking and in four patients the tobacco consumption remained unchanged. For the whole group the evolution was benign, with all patients being asymptomatic or showing improvement in symptoms and regression of radiological signs. CONCLUSION Radiographic studies often provide clues to the diagnosis, but may not obviate the need for open lung biopsy in the majority of cases. Our study shows that irrespective of smoking cessation, spontaneous regression of symptoms and radiological signs and long-term survival are possible.