Pulmonary LCH : Molecular Features
Molecular Features: Most cases (about 70%) of adult pulmonary Langerhans cell histiocytosis (LCH) represent non-clonal, hyperplastic response to cigarette smoking. Clonality and BRAF V600E mutations have been seen in only about 30% of pulmonary LCH cases. These patients may be eligible for targeted therapy with BRAF inhibitor vemurafenib. This low magnification image is from a case of pulmonary LCH. Alveolar spaces at some distance from the LCH nodule are filled with macrophages and there is mild interstitial fibrosis. The picture is not dissimilar from other conditions producing respiratory bronchiolitis/interstitial lung disease.