Figure 2 . Characteristics of hematoxylin & eosin (H&E) andimmunohistochemistry (IHC) staining. (A) Pathological puncture of right lung mass, H&E staining indicated that hyperplasia of the alveolar epithelial was detected in the lesion of the pulmonary tissue, histiocyte reaction emerged in the alveolar cavity, combined with focal necrosis, interstitial fibrosis, and very few atypical cells occurred in the interstitium, with deeply dyed and irregular nucleoli, heteromorphic cells were spindle-shaped and arranged in a sarcomatous pattern. Scale bar, 100 µm. (B-D) IHC staining suggested the tumor cells stain positively for markers, including, Ki67 (65.8%+), TTF-1 (78%+), Vimentin (93.4%+), Scale bars 50 µm.