Adult Langerhans cell histiocytosis with independently relapsing lung and liver lesions that was successfully treated with etoposide

A 35-year-old man initially presented with cough and fever. Computed tomography (CT) revealed diffuse small cysts in the lung, and multiple nodules in the liver. Lung and liver biopsies revealed that pathology was consistent with Langerhans cell histiocytosis. Lung shadows increased despite cessation of smoking, whereas the liver involvement improved. After initiating treatment with prednisolone, the chest CT findings improved. However, the liver nodules started to increase while tapering prednisolone. Intravenous etoposide was started, and the liver nodules decreased markedly. The difference in the clinical course between the lung and liver lesions might have been the result of differences in the clonality of these two organs.