Before a definite diagnosis of ALK-positive histiocytosis, the patient was administered a “lung cancer” regimen [radiotherapy (21 times, total equivalent dose in 2 Gy/f (EQD2): mediastinum and lung 56.5 Gy, Hilar 71.9 Gy) combined with chemotherapy (paclitaxel + cisplatin + bevacizumab)]. Here, ALK is linked to Histiocytosis.