Fig. 3.

Histologic features of pulmonary adenocarcinoma of the pneumonic type A. Low power view of lung tissue shows neoplastic consolidations surrounding terminal bronchovascular bundles (*) in a pattern reminiscent of bronchopneumonia, from which the entity acquires its adjective “pneumonic”. Scale bar = 2 mm. B. An alveolar space occupied the characteristic fibroblastic plug an organizing pneumonia (*). The arrowhead points to a reactive type II pneumocyte with hobnail morphology. Surrounding the alveoli are malignant gland forming cells (#) of the adenocarcinoma. Scale bar = 0.25 mm C. The adenocarcinoma showing both an acinar (left side) and solid (right side) pattern of growth. The inset demonstrates a mitotic figure. Scale bar = 0.25 mm, inset = 0.025 mm. D. A terminal bronchiole lined by neoplastic epithelium (*) is identified adjacent to adenocarcinoma. Scale bar = 0.25 mm.