Pulmonary Langerhans cell histiocytosis: A comprehensive analysis of 40 patients and literature review

Background: Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial disease affecting primarily young adult smokers. In order to highlight the clinical features of the disease, we conducted a retrospective analysis on clinical data of PLCH patients followed at our center; moreover, we reviewed the current literature on PLCH. Method and results: Between January 2004 and July 2014, 40 patients with PLCH were evaluated at our Division. The average patients' age was 40 (± 14) years, and 22 of them were females. Diagnosis was based on search of CD1a + cells in the bronchoalveolar lavage (10 patients), lung biopsy (8 patients), or cystic bone lesion's biopsy (2 patients); in 12 patients, diagnosis was achieved on the basis of the clinical-radiological data. The principal manifestation of PLCH was the presence of cysts involving upper lung zones with costophrenic sparing on chest CT scan (in 25 patients); micronodular pattern in the middle-upper zone and combination of the two radiological patterns were less frequently observed (in 9 and 6 patients, respectively). Pulmonary hypertension was found in 4 patients. Extra pulmonary manifestations were diabetes insipidus, bone lesions, and skin involvement (in 5, 7, and 1 patient, respectively). For 25 patients, smoking cessation was the only required therapy. Treatments with low dose of prednisolone, vinblastine and prednisolone, or 6-mercaptopurin were reserved for patients with major pulmonary or extra-pulmonary involvement (for 11, 4, and 5 patients, respectively). In conclusion, PLCH is a rare, multi-systemic disease; early diagnosis, accurate staging and smoking cessation are considered critical in PLCH management.