Clinical features of pulmonary langerhans cell histiocytosis in Korea

Background: Pulmonary Langerhans cell histiocytosis (PLCH) is characterized by a proliferation of Langerhans cells and this results in granulomas that involve multiple organs of the body. Because the incidence of PLCH is very low in Korea and worldwide, collecting the clinical data of patients with PLCH nationwide is needed to determine the clinical features of Korean patients with PLCH. Methods: The patients with PLCH confirmed by biopsy at any body site were included and the patients should have lung lesions present. A questionnaire that had items on the symptoms, lung function tests, the roentgenographic findings and the treatment was collected retrospectively at a Korean ILD Research Meeting. Results: A total of 56 cases were collected. The number of males and females was 48 and 8, respectively, and their median age was 43 years (range: 18-67 years). The patients were current or ex-smokers in 79% of the cases. The most frequent symptom was coughing (39%), followed in decreasing order by dyspnea (38%), sputum (20%) and chest pain (20%). Pneumothorax was observed in 16 (29%) patients. Lung function tests showed a normal, restrictive, mixed or obstructive pattern in 26 (61%), 7 (16%), 7 (16%) and 3 patients (7%), respectively. Nodular-cystic lesion was most frequently observed in 59% of the patients on HRCT. The lung lesions were located in the middle and upper lobes in almost the cases. The median follow-up period was 90 months (range: 1-180 months) and only two patients died during this period. Conclusion: This study provides a national survey of the patients with PLCH during a long follow-up period.