Signet ring cell carcinoma hidden beneath large pedunculated colorectal polyp: A case report

Figure 1 Contrast-enhanced computed tomography scans of the abdomen showed no specific abnormalities in the left colon.

Figure 2 Multiangle photographs of the pedunculated polyp under colonoscopy. A-C: The pedunculated polyp shows the characteristic features of adenoma with unclear surface pattern; D: The pedunculated polyp was resected under colonoscopy.

Figure 3 The pathologic results for pedunculated polyps and lymph nodes. A: The tumor was composed of signet ring cell carcinoma (dark rectangle, hematoxylin and eosin: 0.52 ×); B: The pathologic result in the rectangle clearly showed that the signet ring cells infiltrated the submucosa (hematoxylin and eosin: 40 ×); C: The lymph node was invaded by signet ring cell adenocarcinoma (blue rectangle, hematoxylin and eosin: 1.32 ×); D: The pathologic result in the rectangle clearly showed that the signet ring cells invaded a lymph node (hematoxylin and eosin: 40 ×).

Figure 4 The treatment strategies for cTis and cT1 colorectal cancer from the Japanese Society for Cancer of the Colon and Rectum Guidelines.