Pulmonary Langerhans cell histiocytosis: radiologic resolution following cessation of second hand smoking.

We present a 65-year-old male former smoker with past medical history of renal cell carcinoma. Surveillance chest CT scan showed numerous progressive bilateral upper lobe predominant nodular cystic densities. A Video Assisted Thoracoscopic Surgery lung biopsy was diagnostic of Pulmonary Langerhans Cell Histiocytosis. Further questioning of the patient revealed exposure to second hand smoke from his wife. A repeat chest CT scan 6 months following cessation of all smoking exposure showed near complete resolution of the nodular densities. Our case report highlights the importance of early identification of second hand smoke exposure. Timely elimination of the exposure led to near complete radiologic resolution.