malignant tumours derived from melanocytes, usually on the skin. can occur in other organs with melanocytes (eyes skin, genitals, oral mucosa, bowel).

<aside> 💡 warning signs:

• new or changing (most melanomas arise de novo rather than from a pre-existing mole)
• prominent and pigmented, and stands out from other moles (‘ugly duckling’)
• rapidly growing (applies to a nodule of any colour)
• of particular concern to the patient
• atypical on dermoscopy (eg asymmetric pigmentation, blue-white veil, multiple brown dots, pseudopods, radial streaming)
• changed on sequential dermoscopy. </aside>

Demographics: 45-64yo, males, rare in children. Increases w/ age.

Risk factors:

• multiple common melanocytic naevi
• family history of melanoma
• marked sun exposure (eg during work and leisure time) and solar skin damage
• blistering sunburns as a child or adolescent
• history of melanoma or nonmelanoma skin cancer
• fair complexion and a tendency to sunburn (fitzpatrick skin type 1)
• (>5) dysplastic or atypical naevi
• solarium use
• immunodeficiency

Clinical features:

• most commonly in sun exposed ares such as nose, cheek ears and upper back.
• pigmented = brown + black + blue, can be amelanotic