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Latest update 16/06/09
Aetiology
- The blue naevus is a derived from melanocytes in the dermis that are thought to have become arrested in fetal life during migration from the neural crest to the dermis
Key diagnostic features
- Age of presentation - Mainly older children and young adults
- Distribution – Common on the face, but can arise anywhere
- Appearance
- Colour – Dense, blue-black lesions
- Shape - Regular
- Often raised but can be flat
- The cellular blue naevus presents as a densely pigmented, often papular, blue-black lesion and is found most often on the wrists and buttocks
Dermoscopic appearance
- Homogenous blue-gray pigmentation
Management
- The appearance of blue naevi can give rise to concern, but the intense pigmentation of blue naevi is uniform, whereas blue-black pigmentation in melanoma is usually admixed with varying shades of brown and red
- A blue naevus only needs to excised if there is diagnositc uncertainty in which case it ought to removed with a 2mm margin of normal skin
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Fig
ure 1 – Blue naevus close up
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Figure 2 – Dermoscopic appearance of figure 1
Note the homogenous blue/grey pigmentation
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Figure 3 – Blue naevus on forehead
The lesion had remained unchanged for as long as the patient could remember
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Figure 4 – Dermoscopic appearance of figure 3
The white regions represent areas of fibrosis that can arise in blue naevi
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Figure 5 - Blue naevus on the forearm
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Figure 6 – Dermoscopic appearance of figure 5
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Figure 7 – Blue naevus
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Figure 8 – Cellular blue naevus on the wrist
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Figure 9 – Blue naevi
This small cluster erupted in a young child
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Figure 10 – Dermoscopic appearance of figure 8
Note the uniform distribution of colour
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