Confocal laser endomicroscopy to guide sampling of a pure ground-glass opacity

a) Pulmonary transverse window image of chest computed tomography scan showing a pure ground-glass opacity of the left lower lobe with bronchus sign. b and c) Position of the catheter in the ground glass opacity during electromagnetic navigation procedure. d and e) probe-based confocal laser endoscopy (pCLE) image comparing a normal versus a lepidic pattern in pCLE with studding alveolar walls and dense acinar elastic network. Scale bar=50 μm. f) Haematoxylin and eosin stain shows an atypical single-cell proliferation lining alveolar walls (magnification 40×). g) Immunohistochemical staining with anti-thyroid transcription factor (TTF)1 antibodies (brown) highlights a TTF1⁺ cell proliferation (magnification 20×).