Melanoma

Malignant Melanoma

Malignancy of melanocytes and naevus cells. Potentially fatal skin tumour. Increasing prevalence due to the more socially acceptable ‘tanned’ appearance  public health campaigns aimed at reducing incidence.

Risk Factors for Melanoma (MMRISK):
Moles – atypical (more than 10)
Moles – common moles (numerous)
Red hair and freckles
Inability to tan – skin phototypes 1 & 2
Sunburn – severe sunburn before age 13
Kindred – family history

Clinical features:
Six Keys Signs:
Asymmetry of shape
Border is irregular
Colour is mottled
Diametre is usually large
Elevation is almost always present
Enlargement – history of increase in Size

Clinical Types:
Superficial spreading melanoma (SSMM):
• most common melanoma (70%) in whites
• appears as slowly enlarging brown (usually) or black raised plaque with indurated margin and irregular border
• more common on legs of females and backs of males – especially ‘fair’ skinned individuals
• often have history of many ‘sunburns’ in childhood and have a predisposing naevus

Nodular melanoma:
• up to 20%
• history of a suddenly appearing ‘lump’ that recently started growing
• appears as an elevated pigmented dark blue/brown/black nodule
• tends to be invasive and ulcerates  ‘nonhealing skin ulcer’
• metastasis to lymph nodes and local organs
• can occur anywhere on body

Lentigo malignant melanoma:
• about 5%
• more common on face and other sun exposed areas
• irregularly shaped, flat pigmented lesions

Acral lentiginous melanoma:
• uncommon type occurring in dark skinned individuals
• appears as a flat hyperpigmented black/brown lesion (macule)
• usually palms, soles and subungual
• slower growing than other forms
• differential diagnosis – blood blister

Clark’s Levels:
System used to describe depth and level of invasion – used to determine probability of the progression of the disease. Correlates to 5 year survival rates.
Level 1 – cells in epidermis only
Level 2 – cells extend from epidermis into (but on completely) papillary dermis
Level 3 – cells extend from epidermis into and fill papillary dermis
Level 4 – cells extend into reticular dermis
Level 5 – cells extend through the dermis into underlying subcutaneous fat

Breslow’s depth:
Assessment of depth of invasion.

Treatment:

Outcome:
For lower extremity primary melanoma’s, the more distal the lesion (ie in the foot), the worse the prognosis and poorer the survival

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