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Types and Stages of Melanoma

A plain-language explanation of melanoma types and how melanoma is staged, including how deep it has grown. Based on the National Cancer Institute.

NCI source

Last reviewed: 2026-07-07

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 highly curable; 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 highly curable with surgery.

  • Staging also looks at whether it has spread to lymph nodes or distant sites.

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The full explanation.

The simple version

Most melanomas start in the pigment-making cells of the skin. Melanoma is staged from 0 to IV, and one of the most important factors is how deep it has grown into the skin. Thin, early melanomas are highly curable.

What staging looks at

Melanoma staging considers:

  • Thickness — how deep it has grown into the skin
  • Ulceration — whether the surface is broken
  • Whether it has spread to nearby lymph nodes
  • Whether it has spread to distant sites (stage IV)

Why depth matters

The thickness of a melanoma is one of the strongest predictors of how it will behave. Thin melanomas are much less likely to have spread and are usually cured with surgery, while thicker ones carry more risk and may need more treatment.

How deep a melanoma has grown is a key factor in its stage and outlook.

How the stage is found

The melanoma is measured after it is removed. For thicker melanomas, a sentinel lymph node biopsy or imaging may be used to check whether it has spread. The stage then guides treatment.

Words to know

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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. Thin melanomas are much less likely to have spread and are highly curable, while thicker ones carry more risk.

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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Types and Stages of Melanoma