Adenocarcinoma of Lung : CK20

Comments:
Adenocarcinoma of lung (non-mucinous type) with lepidic growth pattern. The image shows cuboidal tumor cells that line up along alveolar septa and project into the alveolar spaces. Scattered anthracotic pigment granules are present in the alveolar septa and alveolar spaces. The inset shows the tumor cells are negative for cytokeratin 20. Image courtesy of: Jian-Hua Qiao, MD, FCAP, Los Angeles, CA, USA.