To the editor:Severe acute interstitial lung disease is not uncommon during and after irradiation of the lung,but is very rare during crizotinib treatment.We reported here one case of severe acute interstitial lung disease after one month crizotinib treatment.rnA 53-year-old Chinese male patient with one month dyspnea was admitted to our hospital.He had a smoking history with one pack cigarette a day for 28 years,but denied any other specific family history.Physical examination revealed facial edema,venous distention in the neck,distended veins in the upper chest and arms,enlarged supraclavicular lymph nodes on both sides.Chest CT scan revealed right lung 3.5 cm × 4.5 cm mass with right plural invasion,diffused mediastinal lymph nodes enlargement compressing the superior vena cava.