Fig. 1

Diagnostic images and pathological findings for case 1. a A bronchoscopy revealed a tumor arising from the right middle lobe bronchus. b PET-CT scan revealed no other lesions that could have represented a primary site. c Hematoxylin-eosin staining of the resected tumor, ×40 (scale bar, 100 μm). d Immunohistochemistry showed negative for PD-L1 staining, ×40 (scale bar, 100 μm)