Spread through air spaces in lung adenocarcinoma: is radiology reliable yet?

The concept of tumor spread through air spaces (STAS) in lung adenocarcinoma was officially recognized as a pattern of invasion in 2015 World Health Organization (WHO) classification . The STAS is defined as the presence of “micropapillary clusters, solid nests, or single cells beyond the edge of the tumor into air spaces in the surrounding lung parenchyma” within the surgical specimen ( Figure 1 ), which implies a post - surgical diagnosis (1) .