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The cause of most skin cancers is sun damage to the skin, in particular episodes of sunburn. There are three main types:

  • basal cell carcinoma (BCC)
  • squamous cell carcinoma (SCC)
  • malignant melanoma.

Other types of skin cancer are rare (<1% of UK skin cancers).  

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Lumps and bumps 

All three main types of skin cancer are curable if detected early, by removing affected area. BCCs and SCCs usually grow slowly; some will spread if left to grow, occasionally SCC spreads quite early. Overall cure rate for BCC and SCC is >95%, but the larger they grow, the harder they are to treat. Melanoma is extremely malignant.


Develops in rounded, basal cells of the epidermis. Common, and causes >75% of UK skin cancers. Often starts as a small, red, shiny nodule that may bleed occasionally. May eventually develop into a persistent ‘rodent ulcer,' looking like a small inflamed crater with a raised edge.


Develops in the flattened, surface cells of the epidermis. Causes 20% of skin cancers. Typically starts as a small crusted or scaly area with a red or pink base, and may grow into a lump looking like a wart.

Malignant melanoma

Melanoma develops from melanocytes, cells scattered among the basal cells. Typically starts as a small dark patch; can develop from normal skin or an existing mole. May itch, bleed, crust or ulcerate as it grows. Advice to patients from Cancer Research UK is to see a doctor if they have a mole that is:

  • Getting bigger
  • Changing shape, particularly getting an irregular edge
  • Changing colour - getting darker, becoming patchy or multi-shaded
  • Itching or painful
  • Bleeding or becoming crusty
  • Looks inflamed

Mole or melanoma? ABCD sums up differences:

  • Asymmetry: a melanoma is often uneven and asymmetrical, a mole is usually round and even.
  • Border: a melanoma’s border is often ragged, notched or blurred; a mole has a smooth, well defined edge.
  • Colour: pigmentation of a melanoma is often not uniform, with two to three shades of brown or black, a mole is usually uniform in colour.
  • Diameter: a melanoma is usually larger than a normal mole, and it continues to grow.

Measure the lesion and record a description, eg irregular margins, irregular pigmentation, nodular areas. Note and examine all other pigmented naevi, feel for regional lymphadenopathy, examine for hepatomegaly. Suspicion of melanoma warrants urgent referral to a specialist

Melanomas are extremely malignant. They need urgent early treatment because the risk of metastasis is high.

NICE NG12. Suspected cancer: recognition and referral

Cancer Research UK. Melanoma skin cancer (includes images of abnormal moles)

MacMillan Cancer Support.  Skin cancer.

DermIS. Dermatology Information System. Images of BCC, SCC 

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