CXR Upper Lung Regions Emphysema TB Sarcoidosis Silicosis Hypersensitivity Pneumonitis Langerhans Cell Histiocytosis Langerhans Cell Histiocytosis LANGERHANS HISTIOCYTOSISRETICULONODULAR PATTERN53-year-old female with nicotine dependence presents with dyspnea and coughCXR (PA and Lateral) shows bilateral and extensive reticular nodular changes slightly more prominent in the upper lung zonesCT scan from 16 months prior showed multiple relatively thick-walled cysts predominantly in the upper lobes. The cysts are round and air filled large and are between 5mm-8mmCT scan 9 months later shows improvement in the thickened walls of the cysts but maintenance of diffuse cystic changes predominantly in the upper lobesA CT scan done 2 years later shows no significant change in the diffuse bilateral cystic changes, dominant in the upper lobes and consistent with Langerhans histiocytosisAshley Davidoff MD CT CORONAL VIEW – UPPER ZONES MORE AFFECTED THAN LOWER LUNG ZONES – LANGERHANS HISTIOCYTOSIS53-year-old female with nicotine dependence presents with dyspnea and coughCXR (PA and Lateral) shows bilateral and extensive reticular nodular changes slightly more prominent in the upper lung zonesCT scan from 16 months prior showed multiple relatively thick-walled cysts predominantly in the upper lobes. The cysts are round and air filled large and are between 5mm-8mmCT scan 9 months later shows improvement in the thickened walls of the cysts but maintenance of diffuse cystic changes predominantly in the upper lobesA CT scan done 2 years later shows no significant change in the diffuse bilateral cystic changes, dominant in the upper lobes and consistent with Langerhans histiocytosisAshley Davidoff MD