Natural course of isolated pulmonary langerhans' cell histiocytosis in a toddler. 3-year follow-up.

Isolated pulmonary Langerhans' cell histiocytosis (LCH) is distinctly rare under the age of 15 years, since the majority of patients are young adult males with heavy smoking habits. Isolated pulmonary involvement suggests that antigens inhaled from cigarette smoke are involved. Here we present a case of LCH restricted to the lungs in a toddler whose parents were heavy smokers. Since LCH was not medically treated for 3 years due to parental refusal, the disease can be regarded as having followed its natural course. During the 3-year follow-up, the disease progressed to severe pulmonary fibrosis resulting in honeycomb lungs. Based on the comparative immunohistochemical analyses of the cells obtained from bronchoalveolar lavages during the disease course, it appears that the evolution of fibrosis is rather a result from the accumulating alveolar macrophages than from the persistence of the Langerhans' cells. Passive cigarette smoking may be considered a significant risk factor in both the pathogenesis and development of pulmonary LCH in a small child. Copyright (c) 2008 S. Karger AG, Basel