Figure 7a. Adenocarcinoma with mixed acinar and bronchioloalveolar carcinoma in a 50-year-old woman. (a) Thin-section CT image obtained at the level of the aortic arch shows a 28-mm well-defined mixed ground-glass opacity lesion with peripheral ground-glass opacity in the upper lobe of the left lung. The mass abuts the pleura. (b) Photomicrograph of a histologic specimen (original magnification, x40; hematoxylin-eosin stain) shows a replacement-type growth pattern characteristic of bronchioloalveolar carcinoma in the periphery of the tumor.