Written with men in mind. Most of this guide applies to everyone. Details specific to women — such as screening ages and risks that differ — are not covered yet; female health guides are being written.
What it is
Melanoma is a serious type of skin cancer that starts in the cells that give skin its colour. It often appears as a new mole or a change in an existing one, and it's most treatable when found early.[1][2]
Melanoma arises from melanocytes. Warning features are summarised as ABCDE: Asymmetry, irregular Border, uneven Colour, Diameter usually over 6 mm, and Evolving (changing).[1]
Diagnosis is by excisional biopsy; treatment ranges from wide local excision (with sentinel lymph node assessment where indicated) to immunotherapy and targeted therapy for advanced disease.[2] USPSTF found insufficient evidence to recommend for or against routine visual skin examination in adults without symptoms (I statement, 2023).[3]
Turn on the skin surface layer in the Explorer to see the body's surface regions.
See it in 3DHow common it is
Causes and risk factors
Things you can't change
- Fair skin that burns easily, red or blond hair, blue or grey eyes, many freckles.[1]
- Many moles, or unusual (dysplastic) moles.[1]
- A personal or family history of melanoma.[1]
- A weakened immune system.[1]
Things you can change
Symptoms worth reporting to a doctor
- Asymmetry: one half of a mole doesn't match the other
- Border: ragged, notched or blurred edges
- Colour: uneven shades of black, brown or tan, sometimes red, pink, white or blue
- Diameter: growing; most melanomas are wider than 6 mm
- Evolving: a mole that has changed over weeks or months
- A new mole, or one that itches, bleeds or oozes
Not every melanoma shows all of these. Tell your doctor about any new mole or change in an existing one.[1]
Screening: who, when and how
USPSTF makes no recommendation for or against routine skin exams by a clinician for adults without symptoms (I statement, 2023).[3] Knowing your own skin and reporting changes still matters.[1]
How it's diagnosed
Stages in general terms
In general terms:[5]
- Localised: still where it started.
- Regional: spread to nearby tissue or lymph nodes.
- Distant: spread to other parts of the body.
An illustration, not a stage. Human Atlas never assigns a stage. Only your own tests and your care team can do that.
Types of treatment
- Surgery. Removing the melanoma with a margin of normal skin, sometimes with nearby lymph nodes.[2]
- Immunotherapy and targeted therapy. For melanoma that has spread or is at high risk of returning.[2]
- Other treatments. Chemotherapy and radiation in some situations.[2]
Which option fits depends on the details of each person’s situation. Your care team decides with you.
What you can do
Questions to ask your doctor
- Does this spot need a biopsy?
- How often should my skin be checked, given my risk?
- What did the biopsy show, and do I need more surgery?
Myth vs. fact
Guided lesson
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Sources
- National Cancer Institute. Common Moles, Dysplastic Nevi, and Risk of Melanoma. Checked 24 October 2026.
- National Cancer Institute. Melanoma Treatment (PDQ®) – Patient Version. Checked 23 October 2026.
- US Preventive Services Task Force. Skin Cancer: Screening (April 2023). Checked 24 October 2026.
- American Cancer Society. Key Statistics for Melanoma Skin Cancer (2026 estimates). Checked 23 October 2026.
- National Cancer Institute. Cancer Staging. Checked 23 October 2026.
The owner of this website is not a doctor. Human Atlas provides educational anatomy information and does not diagnose, stage, or treat disease. Talk to a qualified clinician about anything concerning your own health.