Pneumothorax in Patients with Pulmonary Langerhans Cell Histiocytosis.

INTRODUCTION: Pneumothorax often develops in pulmonary Langerhans cell histiocytosis (PLCH), but some patients take a long time to be correctly diagnosed. OBJECTIVES: This study assessed the frequency of pneumothorax in PLCH and analysed the role of chest computed tomography (CT) in the prompt diagnosis. PATIENTS AND MATERIAL: Of the 90 patients with PLCH seen from 2000 to 2015, 29 (32%) had pneumothorax as the initial finding. In this group, 18 (62%) patients were diagnosed within 1 month, whereas the diagnosis was delayed for 4-120 months in 11 (38%) patients. RESULTS: Patients who had pneumothorax as the initial sign of PLCH tended to be younger (mean age 27.7 ± 7.92 vs. 39.9 ± 13.21 years; P = 0.0001), male (69% vs. 43%; P = 0.028), smoked less (mean pack/years 8.4 ± 6.85 vs. 19 ± 17.16; P = 0.003), and had a significantly lower mean FVC (77.96 ± 19.62 vs. 89.47 ± 21.86% pred.; P = 0.015) and FEV1 (68.6 ± 19.93 vs. 79.4 ± 21.48% pred.; P = 0.03 than patients who had no pneumothorax. Recurrent pneumothorax was diagnosed more frequently in the group with a delayed diagnosis (82% vs. 39%; P = 0.02). CT was performed in all of the patients who were diagnosed promptly, but in none of the patients with a delayed diagnosis. CONCLUSIONS: Patients who had pneumothorax as the initial sign of PLCH were younger, more frequently men, and had greater respiratory impairment than those who had no pneumothorax. CT in patients with pneumothorax led to a correct diagnosis of this disease.