Role of surgical intervention in managing gastrointestinal metastases from lung cancer

Figure 3 Microscopic findings of metastatic lung adenocarcinoma in the colon. A: Hematoxylin-eosin staining; × 200. This tumor was characterized by pleomorphic oval nuclei, scant cytoplasm, an irregular glandular pattern (arrow), and invasion of the muscle layer (arrow head) of the colon; B-D: Staining for thyroid transcription factor (TTF)-1 (B), cytokeratin (CK)7 (C), CK20 (D); × 100. In general, CK20 positive means that the tumor originates from the gastrointestinal tract. By immunohistochemistry, the tumor cells located in the lower part of the figure were found to be positive for TTF-1 (B) and CK7 (C), but negative for CK20 (D). The glandular structures in the upper part belong to the colon mucosa.