Cladribine treatment of a young patient with isolated progressive pulmonary Langerhans histiocytosis complicated by invasive aspergillosis

A 19-year-old male cigarette smoker (3 pack-years) with progressive isolated pulmonary Langerhans cell histiocytosis (IPLCH) and recurrent pneumothoraces was admitted with a prolonged air leak.Deterioration in clinical status, cough, and loss of more than 20% of body weight developed following pneumonia at 15 years of age.Two years later the patient was hospitalized.Chest computed tomography (C-CT) revealed thin-walled, bizarre-shaped air-filled spaces, predominantly in the upper and middle lung zones, with sparing of the diaphragmatic regions, consistent with PLCH (Figure 1A; Supplementary material, Figure S1A).Bronchoscopy with