Macroscopy: Two pale tan core biopsies 14mm & 15mm.
Microscopy: The sections show cores of alveolar lung parenchyma with extensive involvement by adenocarcinoma. The tumour shows a predominantly lepidic architecture with atypical cuboidal to columnar epithelial cells lining thickened alveolar septae. Foci consistent with invasive acinar adenocarcinoma are seen with irregular glands surrounded by fibroblastic stroma. In addition, there are areas showing micro-papillary architecture with micropapillary budding present within alveolar spaces.
Conclusion: Adenocarcinoma with lepidic, acinar and micropapillary architecture.