Discovery of primary lung cancer following resection of rectal cancer lung metastasis: A case report

Figure 1 Endoscopic plus mass biopsy and postoperative pathology of a circumferential bulging mass in the rectum. A: Endoscopic image of a malignant rectal tumor; B: Hematoxylin-eosin staining (× 100) of rectal mass biopsy tissue; C: Hematoxylin-eosin staining (× 100) of postoperative rectal mass tissue.

Figure 2 Whole-body computed tomography scan. A: A ground-glass nodule (red arrow) is visible in the outer basal segment of the right lower lobe on the computed tomography scan taken on July 10, 2021; B: A nodule (red arrow) is observed in the outer basal segment of the left lower lobe; C: A ground-glass nodule (red arrow) is visible in the outer basal segment of the right lower lobe on the computed tomography scan taken on January 25, 2022; D: A nodule (red arrow) is observed in the outer basal segment of the left lower lobe on the computed tomography scan taken on January 25, 2022.

Figure 3 Hematoxylin-eosin staining and immunohistochemistry of a tumor in the lower lobe of the left lung. A: Hematoxylin-eosin staining of lung biopsy tissue (× 100); B: CK20-immunostained positive tumor cells (× 100); C: CDX2-immunostained positive tumor cells (× 100).

Figure 4 Hematoxylin-eosin staining and immunohistochemical analysis of the upper and lower lobes of the right lung. A: Hematoxylin-eosin staining of lung biopsy tissue (×40); B: Hematoxylin-eosin staining of lung biopsy tissue (× 100); C: TTF-1-immunostained positive tumor cells (× 100).