Pulmonary Langerhans Cell Histiocytosis in the Elderly Smoker

Langerhans cell histiocytosis (LCH), formally referred to histiocytosis X, is a histiocytic disorder with unknown etiology. The pathogenesis is believed to originate from myeloid dendritic cells and is now considered an inflammatory myeloid neoplasm within the revised 2016 Histiocyte Society classification. Pulmonary Langerhans cell histiocytosis (PLCH) is a rare and isolated form of LCH with a strong affiliation with smoking in adults of 20-40 years of age. Characteristic CT chest and histologic findings are instrumental in the early recognition and management of a disease. We herein report a case of a Caucasian smoker female with a significant history of interstitial lung disease (ILD) presented with recurrent and progressive worsening dyspnea. History of ILD and recurring respiratory symptoms raised suspicion of PLCH. CT chest and pathological findings confirmed the diagnosis, and discontinuation of smoking resulted in favorable clinical outcomes.