The short answer
Melanoma is staged from 0 to IV based mainly on how deep it has grown into the skin and whether it has spread to lymph nodes or beyond. Thin, early melanomas are often treated successfully with surgery; deeper or spread melanoma needs more treatment.
Melanoma is staged from 0 to IV.
How deep the melanoma has grown into the skin (its thickness) is a key factor.
Thin, early melanomas are often treated successfully with surgery.
Staging also looks at whether it has spread to lymph nodes or distant sites.
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Why type matters
This page is for people with melanoma, their families, and anyone checking their skin. It explains the main types and how melanoma is staged.
Melanoma is not one single disease. It is a family of cancers. All of them start in melanocytes, the cells that give skin its color. Most melanomas start in the skin. A few start in other places. This includes the eye, or the lining inside the nose or mouth. Knowing the type helps explain where to look and how the melanoma may appear.
Superficial spreading melanoma: the most common type
About 7 in 10 skin melanomas are superficial spreading melanoma. It usually grows outward across the surface of the skin first, before it grows deeper. Its outward growth can make changes on the skin easier to notice early.
Nodular melanoma: less common, more aggressive
Nodular melanoma makes up about 2 in 10 skin melanomas, according to ACS. It often looks like a raised bump, dark or pink-toned. ACS says it tends to grow into deeper layers earlier, so it is often found at a later stage. A new, raised, fast-growing bump deserves prompt attention. This is true even if it does not look like the classic dark, flat mole.
Lentigo maligna melanoma: slow-growing, in older adults
Lentigo maligna melanoma mainly affects older adults. It usually appears on skin with years of sun exposure, like the face. ACS says it develops gradually and may darken or develop raised areas. A changing patch on sun-exposed skin is worth having checked, not dismissing as an age spot.
Acral lentiginous melanoma: not caused by sun
Acral lentiginous melanoma grows in places sun exposure does not reach. This includes the palms, the soles of the feet, and under the nails. ACS says it makes up a large portion of melanomas in people with darker skin tones. A dark streak under a nail, not caused by injury, should be evaluated. So should a new dark patch on a palm or sole.
Melanoma outside the skin
A small number of melanomas start somewhere other than the skin entirely. Ocular melanoma develops in the eye. Mucosal melanoma starts in moist lining tissue, such as the nose, mouth, or genital area. Both are less common than skin melanoma. ACS lists dark patches or spots in the mouth, nose, or eyes among the signs to have checked.
How melanoma is staged
Type tells you what a melanoma is. Stage tells you how far it has gone. NCI's patient summary numbers the stages 0 through IV.
- Stage 0. Abnormal melanocytes sit in the epidermis, the top layer of skin. They may become cancer and spread into nearby normal tissue.
- Stage I. Cancer has formed, and the tumor is no more than 2 millimeters thick.
- Stage II. The tumor is thicker than in stage I, and stage II is grouped by thickness and by whether the surface is broken (ulceration).
- Stage III. The melanoma has reached nearby (regional) lymph nodes. NCI also groups stage III by tumor features and how many nodes are involved.
- Stage IV. The melanoma has spread to distant sites, such as lung, liver, brain, spinal cord, bone, soft tissue, digestive tract, or distant lymph nodes.
Two features drive the early stages. One is thickness, measured from the surface of the skin down to the deepest part of the tumor. The other is ulceration, meaning the skin over the melanoma is broken.
To work the stage out, the tumor is removed and measured under a microscope. Nearby lymph nodes may be checked, often with a sentinel lymph node biopsy. This removes the first lymph node the cancer would likely reach. NCI lists CT, PET, MRI, ultrasound, and blood tests as other staging tests.
What to check, and how
The ABCDE rule helps evaluate a spot:
- A is for asymmetry, where one half does not match the other.
- B is for a border that is irregular or blurred.
- C is for color that varies within one spot.
- D is for diameter larger than about 6 millimeters, the size of a pencil eraser. Smaller melanomas do exist, though.
- E is for evolving, meaning the spot is changing.
Doctors also use the "ugly duckling" sign alongside ABCDE. A spot that simply looks different from all your other spots is worth a second look, even if it does not clearly break any single ABCDE rule.
What to ask your team
- Which type of melanoma do I have, and how does that affect how it is monitored or treated?
- Should my palms, soles, nails, and scalp be checked, not just sun-exposed skin?
- How often should I have a full skin exam, given my history?
- If a spot changes between visits, how quickly should I be seen?
Sources
Common questions
How is melanoma staged?
Melanoma is staged from 0 to IV, based mainly on how deep it has grown into the skin (thickness), whether the surface is broken (ulceration), and whether it has spread to lymph nodes or distant organs.
Why does depth matter?
The thickness of a melanoma is one of the most important factors. Thickness is one of the factors NCI uses to stage melanoma. Thinner tumors are in the lower stages, while thicker ones are grouped in higher stages.
What is stage IV melanoma?
Stage IV means melanoma has spread to distant parts of the body, such as other skin areas, lymph nodes far from the original spot, or organs. It is treated differently from early melanoma.
How is the stage found?
The melanoma is measured after it is removed, and imaging or a lymph node biopsy may be used to check for spread.
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Last updated: 2026-08-18Next planned review: 2027-07-07
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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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