On the left a chest film of a 19 year old patient with Langerhans cell histiocytosis. The dominant findig on the chest film is a reticular patern and that's about as far as you can go. There is also hyperinflation. No way you would have recognized that this pattern was caused by multiple cysts. This is late stage Langerhans cell histiocytosis. The most challenging differential diagnosis in this patient is centrilobular emphysema. Emphysema however is defined as airspaces without definable walls. Usually we can identify the central dot sign. The upper lobe predominance is not helpfull in the differential as we can appreciate this in many inhalational diseases and also in emphysema. #Clinical #Radiology #CXR #CTChest #LCH #LangerhansCellHistiocytosis #Histiocytosis #Cystic #RadiologyAssistant
