Lung Findings in a Patient with a History of Nicotine Vaping and Cannabis Smoking.

We report a collection of lung findings in a patient with a remote history of cigarette smoking, but now engaged in heavy nicotine vaping with daily edible and combustible cannabis use. Computed tomography (CT) imaging demonstrated numerous, small, and bilateral nodules with ground-glass appearance. The largest nodule is demonstrated in the right upper lung lobe. Clinically the differential diagnosis at this time included hypersensitivity pneumonitis and sarcoidosis. Atypical infection, particularly of a fungal etiology, and metastatic malignancy were also considered. Initial pathology of the right lung needle biopsy revealed alveolar septal thickening with associated atypical pneumocyte proliferation, suggestive of atypical adenomatous hyperplasia (AAH). Subsequently the patient underwent wedge resection of the right upper, middle and lower lobes. Pathology examination revealed pulmonary Langerhans cell histiocytosis (PLCH) in the upper and lower lobes, with CD1a staining highlighting the aggregates of Langerhans cells. Vascular changes were also present including intimal thickening of muscular pulmonary arteries, consistent with pulmonary hypertensive changes. Background lung parenchyma demonstrated respiratory bronchiolitis, smoking-related interstitial fibrosis, an organizing thrombus in muscular artery and associated pneumocyte hyperplasia.