Pulmonary Langerhans cell histiocytosis. (A) High-resolution computed tomography shows multiple bizarre-shaped cysts, especially upper and middle lobe predominance, with almost complete sparing of the costophrenic angles. (B, C, D) Pathologic findings. Histologic features include accumulation of Langerhans and other immune cells around bronchioles (B: H&E, ×40; C: H&E, ×100). Langerhans cells strongly express CD1a on immunohistochemical stain (D: ×100). Diagnosis and treatment of cystic lung disease. The Korean Journal of Internal Medicine. Not Altered. CC.