Melanoma

Melanoma is a malignant tumour of melanocytes. Melanocytes predominantly in occur in the skin but can be found elsewhere especially the eye but there are rare reports of melanomas occurring elsewhere.

Table of contents 1 Causation 2 Behaviour 3 Types of melanoma 4 Symptoms 5 Treatment

Causation

Solar irradiation is the major causative factor and the risk is related to:

• The degree of solar exposure.
• The age at which solar exposure occurs
• Natural skin pigmentation.

Exposure during childhood is a more important risk factor than exposure in adulthood. (This is seen in migration studies in Australia where people tend to retain the risk profile of their country of birth if they migrate to Australia as an adult). Fair and red-headed people are at greater risk.

Other risk factors include the "Dysplastic naevus syndrome[?]" which is a familial condition of atypical moles carrying a low to moderate risk of acquiring melanoma.

Behaviour

The behaviour of melenoma relates mostly to its depth at the time at which it is discovered. Thin melanoma (<0.75mm) have a good prognosis or cure is likely after excision. Once a melanoma spreads it is often a very aggressive tumour.

Features that affect prognosis include depth in mm (Breslow depth[?]), depth related to skin structures (Clarke), type of melanoma, presence of ulceration, presence of satellite lesions, presence of spread.

Types of melanoma

• Superficial spreading (often fairly thin).
• Nodular (often deeper)
• Acral lentiginous (on soles and palms).
• Hutchinsons melanotic freckle (often in older patients).

Symptoms

None: often just noticed as a changing pigmented skin lesion.

• Itch
• Ulceration and bleeding.

Treatment

Surgical excison - usually curative in thin lesions. Immunotherapy and to a lesser extent chemotherapy may have a somewhat experimental role in advanced tumours.