Abstract Introduction Pulmonary Langerhans cell histiocytosis (PLCH) is a rare diffuse parenchymal lung disease characterized by the clonal proliferation of Langerhans cells and cystic lung remodeling. The vast majority of adults with PLCH have a history of smoking with a dose-dependent relationship between smoking exposure and disease severity. A substantial proportion of patients experience disease stabilization or regression after smoking cessation. We report a case of advanced disease despite minimal tobacco exposure. Description A 29-year-old male with a 4 pack-year smoking history presented with progressive dyspnea, polyuria and polydipsia. Physical exam was notable for subcutaneous emphysema, respiratory distress, and decreased breath sounds in the right lung. A chest x-ray revealed a spontaneous right-sided pneumothorax, prompting chest tube placement. CT chest showed multiple diffuse cysts with upper lobe predominance. Right lung wedge resection revealed multiple pigmented alveolar macrophages, presence of eosinophils and fibrin aggregates and interstitial clusters of CD1a and S100-positive cells, suggestive of PLCH. Multiple doxycycline pleurodeses and endobronchial valves were required for eventual resolution of the refractory right pneumothorax. MRI brain along with central diabetes insipidus laboratory results were consistent with suspected extrapulmonary involvement. Despite smoking cessation for seven months, the patient presented again with worsening dyspnea. Repeat CT chest revelated persistent cystic findings, and a large right-sided air collection consistent with a retained pneumothorax. Discussion This case challenges the conventional understanding of PLCH as a condition with dose-dependent smoking exposure correlating to disease severity and prognosis. Evidence of extrapulmonary involvement, retained pneumothorax and lack of regression of the disease despite smoking cessation are rare characteristics. Our case demonstrates that severe PLCH and extrapulmonary complications can occur in patients with minimal smoking exposure and may remain persistent or progressive despite smoking cessation. This abstract is funded by: None
Moreno et al. (Fri,) studied this question.