Pulmonary Langerhans' cell histiocytosis in adults.

Elżbieta Radzikowska

doi:10.5603/arm.a2017.0046

Abstract

Pulmonary Langerhans' cell histiocytosis (PLCH) is a rare disorder of unknown cause characterised by the infiltration of the lungs and other organs by the bone marrow derived Langerhans' cells, which carry mutations of BRAF gene and/or NRAS, KRAS and MAP2K1 genes. It occurs predominantly in young smokers, without gender predominance. The disease is characterised by formation of eosinophilic granulomas with the presence of Langerhans' cells infiltrating and destroying distal airways. High-resolution computed tomography of the chest (HRCT) plays an outstanding role in PLCH diagnosis. The typical radiological picture of PLCH is the presence of small intralobular nodules, often forming 'tree in bud' lesions, cavitated nodules, thin- and thick-walled cystic lesions frequently confluent. Definite diagnosis requires the finding of characteristic lesions in histological examination and demonstration of antigen CD1a or CD207 presenting cells in immunohistochemistry. Smoking cessation is the most important recommendation for PLCH patients. There are no evidence based data regarding systemic steroid therapy. The treatment of progressive PLCH is based on cladribine or cytarabine as salvage therapy. The prognosis is good, and over 85% of patients survive 10 years.

Highlights

Pulmonary Langerhans’ cell histiocytosis (PLCH) belongs to a group of rare cystic pulmonary diseases, including the following disorders: lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, light chain disease, lymphocytic interstitial pneumonia (Table 1)
PLCH is of proliferative nature but its pathogenesis is associated with a reactive, inflammatory element [1,2,3]
Langerhans’ cells (LC) are of myeloid origin and over half of them express BRAF V600E oncogene, and in 25% of cases, mutations within the NRAS, KRAS, MAP2K1 kinase genes are observed

Summary

Introduction

Pulmonary Langerhans’ cell histiocytosis (PLCH) belongs to a group of rare cystic pulmonary diseases, including the following disorders: lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, light chain disease, lymphocytic interstitial pneumonia (Table 1). In the case of isolated involvement of the lungs in adults (pulmonary Langerhans’ cell histiocytosis — PLCH) policlonal proliferation of LC occurs with the presence of significant inflammatory process [1,2,3,4,5,6,7]. Under the influence of tobacco smoke, bronchial epithelial cells and fibroblasts release GM-CSF, which is a strong mitogenic factor for LC Excessive expression of this factor within histiocytic infiltrates has been shown. Tobacco smoke induces inflammatory process in the small airways, the release of a series of proinflammatory cytokines, and the recruitment of macrophages, dendritic cells, monocytes, eosinophils and lymphocytes, which form inflammatory histiocytic granulomas.

13. Bronchoaveolar lavage

Findings

Conclusion