Figure 2a. Noguchi type A adenocarcinoma (localized BAC) in a 63-year-old woman. (a) Transaxial thin-section (1-mm collimation) CT scan (lung window) obtained at the level of the apical segmental bronchus of the right upper lobe shows a 10-mm nodular area of ground-glass attenuation (arrow). (b) Low-power photomicrograph (original magnification, x4; hematoxylin-eosin [H-E] stain) of a surgical specimen shows tumor cells growing along the alveolar walls (lepidic growth) (arrows), which appeared as nodular ground-glass attenuation at CT. The alveolar walls are mildly thickened. The surgical specimens showed no hilar or mediastinal nodal metastasis, and no recurrence was seen at postoperative follow-up.