• Malignant tumour arising from the melanocytes in the skin
    • Spread via lymph and/or blood
  • Incidence ~5-20/100,000/year and rising
    • Not that most patients will have a mole (melacytic naevus) which is benign
  • 4 subtypes: superficial spreading, nodular, lentigo maligna and acral lentiginous
  • More common in women than men but more men die of it

Risk factors/Aetiology

  • Approximately 50% of melanomas arise from a pre-existing naevus.
  • There are several lesions which can be considered precursors to melanoma e.g. common acquired naevus (freckle); melanocytic naevus (mole); actinic lentigines
    • Many of theses (or a tendency to freckly), along with type I skin, increases the risk of transformation into melanoma
    • >100 common naevi and >2 atypical naevi (>5mm diameter or on unusual sites e.g. buttocks, scalp, ears, hands/feet) increases the risk dramatically
  • UV/Sun overexposure
  • Age
  • There is a genetic/hereditary component to some degree (familial cases can be associated with genetic traits e.g. tumour suppressor dysfunction of the CDKN2A gene)
  • Previous skin cancer


  • Typically affects the legs in women and the back in men
  • Slowly enlarging, macular, pigmented lesion with increasing irregularity in shape and pigment
    • Radial growth phase can last 2 years.  Subsequently, the lesion can become palpable and the vertical growth phase (invasive)
    • NB in nodular melanoma, there is classically a rapidly growing nodule that can bleed/ulcerate which may or may not be deeply pigmented (can be confused with vascular lesions but pigment can usually be visualised using a dermatoscope)
  • Features of the lesion
    • 7 point checklist (>=3 suspicious)
      • Major (2 points)
        • Change in size
        • Irregular shape/border
        • Irregular colour
      • Minor (1 point)
        • >6mm in largest diameter
        • Inflammation
        • Oozing or crusting
        • Change in sensation (e.g. itch)
      1. Asymmetry
      2. Border Irregularity
      3. Colour variation/changes
      4. Diameter >6mm
      5. Elevated or Evolution (i.e. change in characteristics)
      6. Firm
      7. Growth


  • Excision biopsy with 2mm margin
    • Breslow thickness/T staging
      • Distance from skin surface
        • T1 <1mm
          • NB in these cases the Clark level should also be documented i.e. what level of skin has been invaded
            • Level 1 is generally in situ melanoma (confined to the epidermis)
            • Level 2- papillary dermis
            • Level 3- reticular dermis
            • Level 4- reticular/deep dermis
            • Level 5- subcutaneous (fat)
        • T2 1-2mm
        • T3 2-4mm
        • T4 >4mm
    • Pathology should also try to identify any lymphovascular invasion and whether there is any ulceration (these are important for prognosis/choice of treatment)
  • Sentinal lymph node biopsy
    • Particularly if tumour is ≥1mm deep
  • Imaging (chest CT/liver USS/Abdominal CT/PET imaging) can also be done if tumour is ≥1mm, a


  • Surgical excision is the primary treatment for locoregional disease (stage I-III i.e. not metastatic disease)
    • Margin depends on breslow staging
      • T1 – 1cm
      • T2 – 1-2cm
      • T3/4 – 2cm
  • For metastatic disease,
    • Dacarbazine can be used but response rates are poor and really only improves survival by several months
    • Radiotherapy/surgery can be of limited use for palliation of symptoms caused by metastases
  • Prognosis can be estimated using Cochran’s Equation

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