Figure 4.

(A, D) Baseline axial (A) and coronal (D) CT images of STAS-positive adenocarcinoma in a 51-year-old man. An irregular ground glass nodule with multiple cystic cavities was detected with clear edges, so he was recommended 6–12 months follow-up (B, C, E). Axial CT images on the 8-month follow-up (B, C). The entire size of the lesion did not change, but some cysts were larger than before, and a ground glass ribbon sign was newly found on the edge of the lesion (black arrow), which was defined as a CT finding of a band-shaped ground glass opacity with blurred edge that emits from the edge of the nodule and extends into the adjacent lung (E). Coronal reconstructed image clearly shows the ribbon sign, stretching to the adjacent visceral pleural (black arrow) (F). The patient was recommended lung lobe resection and was confirmed invasive adenocarcinoma with STAS pathologically. Photomicrograph shows single cell pattern STAS consisting of scattered discohesive single cells (green arrow).