Presentation of pulmonary Langerhans cell histiocytosis before the development of lung cysts.

Pulmonary Langerhans cell histiocytosis (PLCH) affects mainly young, predominantly smoking adults with a peak at 20-40 years of age. Patients with PLCH often present with a nonproductive cough and/or dyspnea. High-resolution CT (HRCT) is the most important diagnostic modality in PLCH. The typical HRCT pattern combines small poorly limited nodules, cavitated nodules, and finally thick- and thin-walled cysts. In rare cases, HRCT enables PLCH to be diagnosed prior to the development of cysts.