Figure 3

Histopathology of the resected lung tissue. (a) Photomicrograph (hematoxylin-eosin stain; original magnification, ×2) shows a focal area of alveolar wall thickening with preservation of the intraalveolar airspaces, consistent with the focal GGO on thin-section CT (arrow). Partial collapse of this lesion is due to an artifact during the process of specimen production. (b) Photomicrograph (hematoxylin-eosin stain; original magnification, ×10) shows alveolar wall thickening with fibrosis, and congestion(arrows). Alveolar bronchiolizations are also seen (arrowheads). (c) Photomicrograph (elastica Masson stain; original magnification, ×4) near the focal fibrosis shows dilated arterioles (asterisk) with markedly thickened walls, one of which have resulted in luminal obliteration (black arrow), as well as dilated venules (white arrows). A transition from arteriolar wall to venular one is seen, suggesting a direct communication between them (arrow head).