The short answer
On a melanoma pathology report, ulceration means the top layer of skin over the tumor has broken down. The pathologist records it as present or absent. It is used with Breslow depth to set the T category, and it is the "a" or "b" after the T number. This page explains the finding.
Ulceration means the top layer of skin over the melanoma has broken down, as seen under the microscope.
It is recorded as present or absent, and it is used with thickness to set the T category.
"b" after a T number (for example T2b) means ulceration is present. "a" means it is not.
Ulceration can move a melanoma into a higher stage group. Your care team explains what that means for you.
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This page is for anyone whose melanoma pathology report says "ulceration present" or "ulceration absent." It explains what the finding means and how it is used in staging.
What ulceration means
NCI describes ulceration as a hole that forms in the skin "when the top layer of cells breaks down and the tissue below shows through."
On a pathology report, this is a microscope finding. The pathologist looks at the skin over the tumor and records whether ulceration is present or absent. You may or may not have seen a sore or bleeding on the spot yourself.
How ulceration is used in staging
In melanoma, the T category is set by two things: Breslow depth and ulceration. The thickness gives the number. Ulceration gives the letter.
- "a" after the T number (for example T2a) means no ulceration.
- "b" after the T number (for example T2b) means ulceration is present.
T1 is a little different. NCI lists T1b as under 0.8 mm with ulceration, or 0.8 to 1.0 mm with or without ulceration.
In NCI's stage groups, ulceration can move a melanoma into a higher group. For example, a tumor 1 to 2 mm thick is stage IB without ulceration and stage IIA with it.
Why it matters to your team
NCI lists ulceration among the factors that affect outlook and treatment choices, along with thickness and lymph node findings.
This describes groups of people, not you. Many things shape each person's plan. Your care team can explain what an ulcerated or non-ulcerated result means in your case.
Ulceration is not the same as a wound problem
On a report, ulceration describes the tumor itself. It is not about how a biopsy site is healing. If a biopsy or surgery site is red, swollen, draining, or you have a fever, call your care team. For heavy bleeding that will not stop, call 911.
Ask these before you leave
- Is ulceration present or absent on my report?
- What is my Breslow depth, and what T category do the two give me?
- How does ulceration affect my stage group?
- Does it change the next steps you recommend?
Related pages
See What Does Breslow Depth Mean?, Melanoma Stages, What Does Mitotic Rate Mean?, and Understanding Your Pathology Report.
Sources
Common questions
What does ulceration mean in melanoma?
NCI describes it as a hole that forms in the skin when the top layer of cells breaks down and the tissue below shows through. On a report, the pathologist says whether it is present or absent.
Is ulceration the same as a sore I can see?
Not always. The pathologist decides based on the microscope. You may or may not have noticed a sore or bleeding.
What does T1b or T2b mean?
The number comes from thickness. The letter "b" means ulceration is present (for T1b, a thickness of 0.8 to 1.0 mm also counts).
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Sources last checked: 2026-09-27 what this meansLast updated: 2026-09-27Next planned review: 2027-09-27
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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