Where can melanoma develop and what does it look like?

Melanoma sometimes develops inside an existing mole, but it is very often an entirely new skin growth.

In people with light skin, commonly affected areas include the chest and back in men, and the lower legs in women. But melanoma can occur anywhere on your body – even in places hardly ever reached by sunlight, like your scalp, genital area or beneath your toenails or fingernails.

On light skin, melanoma typically looks like a flat, dark, irregularly colored spot or patch. It may be brown or black, bluish, reddish or – in rare cases – even white or partly skin-colored. Sometimes melanomas appear as slightly raised brownish-black bumps.

Older people may develop a pre-cancerous condition called lentigo maligna. This appears as brown to dark-brown patches of skin with irregular color. The patches are most often found on skin that is frequently exposed to sunlight.

Melanoma skin cancer may look like this on light skin:

On dark skin or very dark skin, it’s often harder to recognize melanoma. Sometimes it just looks like a somewhat darker spot on dark skin, so it might not stand out as much. But it may be colorless, pink or red instead. It also typically develops on other parts of the body than it does in people with light skin. For example,

• the soles of the feet or the skin between the toes,
• the palms of the hands or the skin under the nails,
• the eyes or mouth, and
• the genitals.

What's more, people with dark skin often have harmless dark stripes or patches that are hard to tell apart from melanoma. These are especially common under the nails, on the lips and inside the mouth.

Melanoma skin cancer may look like this on dark skin:

What is the ABCDE rule about and what is the “ugly duckling” rule?

Healthy moles are usually round or oval in shape and tend to be only one color. They normally aren't very big (less than 5 millimeters in diameter).

The following ABCDE checklist can help to tell melanoma apart from a normal mole:

The ABCDE rule helps to recognize melanoma, regardless of the color of your skin. But not all criteria apply to every melanoma: For instance, if it starts growing on normal skin (not in an existing mole), it often has a smaller diameter than 5 millimeters.

If you have a lot of moles and aren’t sure how to best keep track of them all, it might help to look out for an “ugly duckling” that stands out from the crowd. This can make it easier to spot abnormal changes in the skin.

In Germany, statutory health insurers cover the costs of skin cancer screening every two years in people aged 35 and over.

Sources

• Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), Deutsche Krebsgesellschaft (DKG), Deutsche Krebshilfe (DKH). S3-Leitlinie Prävention von Hautkrebs. AWMF-Registernr.: 032-052OL. 2021.
• Bendick C. Besonderheiten der nichtweißen Haut. In: Braun-Falco's Dermatologie, Venerologie und Allergologie. Berlin: Springer; 2017.
• Dadzie OE, Petit A, Alexis AF. Ethnic Dermatology: Principles and Practice. Hoboken: Wiley-Blackwell; 2013.
• Gloster HM, Neal K. Skin cancer in skin of color. J Am Acad Dermatol 2006; 55(5): 741-760; quiz 761-744. [PubMed: 17052479]
• Hogue L, Harvey VM. Basal Cell Carcinoma, Squamous Cell Carcinoma, and Cutaneous Melanoma in Skin of Color Patients. Dermatol Clin 2019; 37(4): 519-526. [PubMed: 31466591]
• Jackson BA. Nonmelanoma skin cancer in persons of color. Semin Cutan Med Surg 2009; 28(2): 93-95. [PubMed: 19608059]

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