Figure 12a. Case 3. (a) Axial CT scan of a 16-year-old patient with LCH shows multiple cysts, some small and thick walled and others much larger and thin walled. (b) Low-power photomicrograph (original magnification, x30; H-E stain) of the patient's lung biopsy specimen shows two cysts (*), the walls of which are lined with histiocytic cellular infiltrate.