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Mucinous and signet ring cell colon cancer: what the words mean | CION Cancer Clinics
Mucinous and signet ring cell are two uncommon subtypes of adenocarcinoma, the usual type of colon cancer. Mucinous means the tumour makes large pools of mucus. Signet ring cell means the mucus is trapped inside each cancer cell. This page explains both words, how they differ, the extra checks they lead to, and what only your oncologist can tell you. At CION Cancer Clinics in Hyderabad, our oncologists explain colon cancer in plain words and plan care around you and your family.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed October 2026, next review due October 2027
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On this page
- What do mucinous and signet ring cell mean on a colon report?
- Which of these words is actually on your report?
- How do the two subtypes compare?
- What happens once a report names one of these subtypes?
- What do families get wrong about these subtypes?
- What this page cannot tell you
- Common questions about mucinous and signet ring colon cancer
The short answer
What do mucinous and signet ring cell mean on a colon report?
Both are uncommon subtypes of adenocarcinoma, the usual kind of colon cancer. Mucinous means the tumour makes a lot of mucus, a jelly-like fluid. Signet ring cell means the mucus collects inside each cancer cell. These words describe how the cancer looks under the microscope. They do not, on their own, give your stage.
Mucinous adenocarcinoma
The lining of the colon normally makes a little mucus to help stool move. In a mucinous cancer, more than half of the tumour is made of pools of mucus with cancer cells floating in it. It is seen more often on the right side of the colon, in younger people, and in cancers with a faulty DNA-repair system, reported as MSI-high.
Signet ring cell carcinoma
Here the mucus stays trapped inside the cell. It pushes the centre of the cell to one edge, so under the microscope it looks like a ring with a stone set on it. This subtype is rare in the colon. It tends to be found later and to spread along the lining of the abdomen, so doctors treat it as a higher-risk type and plan with extra care.
If you have not read it yet, the page on adenocarcinoma of the colon explains the main word first.Four phrases, four meanings
Which of these words is actually on your report?
The wording is precise. A small change in phrase changes what the pathologist is telling your oncologist.
Mucinous adenocarcinoma
Mucus makes up more than half of the tumour. It is a recognised subtype, and the pathologist names it so the tumour board can weigh it alongside the stage and the molecular results.
Often looks like
- A tumour in the right side of the colon
- A larger tumour at diagnosis
- MSI-high or MMR-deficient on testing
Signet ring cell carcinoma
Signet ring cells make up more than half of the cancer. It is always counted as a poorly differentiated, high-grade cancer, and it has a known habit of seeding the lining of the abdomen.
Often looks like
- A younger person than usual
- Cancer found at a later stage
- Spread to the peritoneum rather than the liver
With mucinous features
Mucus is present but makes up less than half of the tumour. This is a usual adenocarcinoma with a mucinous part, not the mucinous subtype. It is planned like any other colon cancer of the same stage.
With signet ring cells present
A few signet ring cells are seen, but they do not make up most of the cancer. The pathologist still mentions them because even a small share can matter, and your oncologist will weigh it.
Not sure which line you have? Read the diagnosis line exactly as written to your oncologist.Not sure whether this applies to you?
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How do the two subtypes compare?
Mucinous
Signet ring cell
Mucus pools outside the cells
Mucus trapped inside each cell
Uncommon, but met regularly in clinic
Rare in the colon
Grade decided case by case
Always treated as high grade
Often MSI-high
Sometimes MSI-high
After the report
What happens once a report names one of these subtypes?
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The pathologist confirms where it started
Signet ring cells are more typical of stomach cancer, so special stains are used to prove the cancer began in the colon. Sometimes an endoscopy of the stomach is arranged as well. CION coordinates this with its partner laboratory and endoscopy unit.
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Staging scans are read with mucus in mind
A CT of the chest, abdomen and pelvis is done at a diagnostic partner. Mucinous tumours can show up faintly on a PET-CT, so a quiet PET scan is read with caution. The page on when a PET-CT is needed explains why.
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Molecular tests are completed
MSI or MMR testing is done for every colon cancer and matters even more here, because these subtypes are linked to it. If the cancer has spread, RAS and BRAF testing follow.
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The tumour board weighs the subtype with the stage
CION's medical and surgical oncologists review the pathology and scans together. Surgery is planned by CION's surgical oncologists and carried out at an accredited partner hospital. If the lining of the abdomen is involved, they discuss whether more extensive surgery is suitable.
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Commonly believed
What do families get wrong about these subtypes?
"Signet ring cell means nothing can be done."
It is a harder subtype, and doctors are honest about that. But a cancer found within the bowel wall is still operated on with the aim of removing it completely. Chemotherapy, and for some people immunotherapy, are still offered.
"Mucinous always means a worse outlook."
Doctors still debate this. Much depends on the stage and the MSI result. An MSI-high mucinous cancer can behave quite differently from one that is not, which is why the molecular test matters so much.
"There is mucus in my stool, so I must have mucinous cancer."
Mucus in stool is common and usually comes from piles, a fissure or irritable bowel. The subtype is a microscope finding on a biopsy, not something seen in the toilet. The page on mucus in stool covers what does need checking.
"The PET-CT was clear, so it has not spread."
Mucinous tumours can take up little of the tracer a PET scan relies on. A clear PET is helpful but not the last word, and the tumour board reads it alongside the CT and the operation findings.
Being straight with you
What this page cannot tell you
It cannot tell you your stage or your outlook. The subtype is one factor among several. Stage, grade, lymph nodes, the MSI result and how well you are overall all count, and only an oncologist who has seen your reports and scans can put them together. Searching survival figures for a rare subtype online usually finds small, old studies that do not describe you.
It cannot settle a borderline report
Whether mucus makes up more or less than half of a tumour is a judgement, and a small biopsy may not show the whole picture. The final subtype is often confirmed only after surgery. If the wording is uncertain, a second review of the slides at a partner laboratory is a reasonable request.
Who this does not apply to
If your report says adenoma or polyp without the word carcinoma, you do not have cancer, even if mucin is mentioned. Mucinous tumours of the appendix behave differently and are covered on the appendix cancer page. If the cancer began in the rectum, the rectal cancer hub is the right place.
Unsure what your report says? Call the helpline and read the diagnosis line aloud. Someone will explain it plainly.Questions we are asked
Common questions about mucinous and signet ring colon cancer
Is mucinous colon cancer more dangerous?
Not always. Mucinous cancers are often larger and found on the right side, and some studies link them to a poorer response to chemotherapy. Others find the difference disappears once stage and MSI status are taken into account. Your oncologist judges it for your case.
Can signet ring cell colon cancer be treated?
Yes. If it is confined to the colon and nearby lymph nodes, surgery with chemotherapy afterwards is the usual plan. If it has spread, chemotherapy is the main treatment, and immunotherapy is considered when the cancer is MSI-high. The tumour board decides the order.
Why did they check my stomach when the cancer is in the colon?
Signet ring cells are more common in stomach cancer, so the doctors must be sure the cancer did not start there and spread to the bowel. An endoscopy of the stomach, plus special stains on the tissue, settles the question. It changes which treatment is chosen.
Does chemotherapy work on mucinous cancer?
It is still used, and it is still worthwhile for many people. Some evidence suggests mucinous tumours respond less well to standard chemotherapy, so results are watched closely. The regimens are the same ones used for other colon cancers.
Is mucinous or signet ring colon cancer hereditary?
Usually not, but both are linked to MSI-high cancers, and some MSI-high cancers come from Lynch syndrome, an inherited condition. If your MMR result is abnormal, a blood test for an inherited fault is offered. The page on Lynch syndrome explains this.
What is peritoneal spread, and why is it mentioned?
The peritoneum is the thin lining of the abdomen. Both subtypes, signet ring especially, can spread along it. In carefully chosen people, surgery to remove the visible disease with heated chemotherapy, called HIPEC, is considered at a partner hospital.
Is immunotherapy an option for these subtypes?
Only if the cancer is MSI-high or MMR-deficient, which is more common in mucinous tumours. For advanced MSI-high colon cancer, immunotherapy is an established option that CION gives at its centres. For cancers that are not MSI-high, it is not usually offered.
Should the biopsy slides be reviewed again?
It is often worth asking when a rare subtype is named, particularly signet ring cell or a report with uncertain wording. A second pathologist can confirm the subtype and where the cancer started. CION's oncologists can arrange a slide review through a partner laboratory.
Your Specialists
Meet CION's colon cancer specialists. Bring your colonoscopy, scan or biopsy report.
Our surgical and medical oncologists plan colon cancer care together: which operation, whether chemotherapy is needed, and the follow-up that comes after.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
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Sources
- Cancer Research UK — Stages, types and grades of bowel cancer
- American Cancer Society — What Is Colorectal Cancer?
- National Cancer Institute — Colon Cancer Treatment (PDQ), Health Professional Version
- National Cancer Institute — Surgical Pathology Reports
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Adenocarcinoma of the colon explainedThe main word your subtype belongs toWhat MSI-high status meansThe test result these subtypes are most linked toPeritoneal spread in colon cancerWhere signet ring cancers tend to travel, and what is doneReading your colon biopsy reportThe other lines on the same report
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