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5 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Signet ring cell carcinoma is a rare form of bowel cancer, about one in a hundred, in which the cells fill with mucus that pushes the nucleus aside, like a ring. It occurs in younger people, favours the right colon, is usually found at an advanced stage and often spreads across the lining of the abdomen, so its outlook is poor; it is treated like other bowel cancer for want of trials of its own.
The WHO classification defines signet ring cell carcinoma by signet ring cells making up more than 50 percent of the tumour (Nagtegaal 2020). The review evidence associates it with young age, proximal site, advanced stage, high grade, frequent node involvement, peritoneal metastasis and significantly shorter survival; molecularly, the classic WNT, RAS-MAPK and PI3K pathways are mutated less often than in ordinary adenocarcinoma while RNF43, CDH1, SMAD4 and TGF-beta pathway genes are altered more often, and many but not all studies report more BRAF mutation and microsatellite instability (Pathology Oncology Research 2021). In the meta-analysis, signet ring cell patients were younger and twice as likely to have right-sided disease (odds ratio 2.12), and five-year overall survival was worse than adenocarcinoma (hazard ratio 2.54 for signet ring and mucinous combined) (Discover Oncology 2021). In the Munich registry it was diagnosed at more advanced stages, with reduced survival (J Cancer Res Clin Oncol 2016).
How it differs from its parent: it is the histology with the worst outlook among colorectal cancers and with peritoneal rather than liver spread, and it shares its cell type and CDH1 biology with diffuse gastric cancer rather than with ordinary colon adenocarcinoma.
| Setting | Approach | Guideline |
|---|---|---|
| All stages | Treated as the colorectal page by stage and mismatch repair status; no trial in the type. | not mapped |