Melanoma
The most serious form of skin cancer, arising from the pigment-producing cells of the skin. It often shows as a new or changing mole. Caught early, it is usually curable by removing it — which is why recognising a changing mole and getting it checked matters so much.
What it is
Melanoma is a cancer of melanocytes, the cells that give skin its colour. It most often appears on the skin as a new spot or a change in an existing mole, though it can also occur in less visible places such as under a nail, on the soles, or rarely inside the eye. Risk is increased by ultraviolet exposure (sun and sunbeds, especially episodes of burning), fair skin that burns easily, many or unusual moles, and family history. What makes melanoma both serious and hopeful is timing: unlike most internal cancers, it is often visible on the skin, and when found and removed early, while still thin and confined to the surface, it is usually cured. Left to grow deeper, it can spread to lymph nodes and other organs, which is much harder to treat — though even advanced melanoma is now treated far more effectively than in the past. The warning signs are usually visual, often summarised as the ABCDEs of a mole (Asymmetry, irregular Borders, varied Colour, larger Diameter, and Evolving/changing), or simply a mole that looks different from the rest or is changing. Diagnosis is by removing the suspicious lesion and examining it; blood markers such as S100 and LDH are used only to monitor advanced disease.
Key lab markers
- Skin examination and removal (excision biopsy) of a suspicious mole — how melanoma is diagnosed; a blood test cannot diagnose it.
- The ABCDE features of a mole — Asymmetry, Border, Colour, Diameter, Evolving.
- S100 (S100B) — a blood marker used to monitor advanced melanoma, not to screen.
- LDH — a marker of disease activity in advanced melanoma.
- Lymph node assessment and imaging — used to check for spread in confirmed cases.
Symptoms
- A new mole, or an existing mole that changes in size, shape or colour
- A mole with an irregular outline, uneven colour, or that is asymmetrical
- A mole that is itchy, bleeds, or does not heal
- A spot that looks different from your other moles
- A dark streak under a nail (uncommon)
- Rarely, symptoms of spread in advanced disease
Related symptoms
When to discuss with a doctor
Get a mole or skin spot checked by a doctor if it is new and looks unusual, or if an existing mole is changing — in size, shape, colour or outline — or becomes itchy, bleeds, or does not heal. The change matters more than any single appearance, so a mole that is evolving or looks different from your others is worth showing to a doctor promptly. People with fair skin, many moles, a history of sunburn or a family history of melanoma should be especially alert and consider regular skin checks. Because early melanoma is usually cured by simply removing it, timely assessment is genuinely worthwhile and not something to put off. Blood markers like S100 and LDH play a role only in monitoring known advanced disease. Mediora.AI can surface those markers in context, but a suspicious or changing mole is assessed by looking at the skin — please have it checked by your doctor.