Pulmonary langerhans cell histiocytosis: Can it originate from chest trauma?

Langerhans cell histiocytosis (LCH) is a rare medical condition which is defined by abnormal accumulation of a heterogeneous population of Langerhans cells that form nodules in certain tissues such as the skin, bone, and lungs. When the lungs are involved, the disease is called pulmonary LCH (PLCH). It is well established that PLCH is frequently observed in young adult smokers with equal gender distribution. Despite the clear role of smoking in PLCH pathogenesis, being a smoker rarely induces the disease, suggesting that host-related factors, inhaled antigens, or other stress-related factors may contribute to the pathogenesis. Here, we reported two cases of PLCH which both presented after chest trauma. Based on the findings from both the cases, it is concluded that the overstimulated inflammatory response in the posttraumatic lungs might be the responsible etiology resulting in the LCH if the lungs are already damaged and more sensitive due to smoking. We suggest that the differential diagnosis of PLCH should be especially considered in young adults with sudden or insidious onset of symptoms following chest trauma.