Blue skin lesions – 7 cases

Blue skin lesions may be due to melanocytic lesions, vascular lesions or exogenous pigment. Dermoscopy may be useful to distinguish them.

Melanin is normally a brown colour. Melanocytic lesions tend to be blue in colour if the melanin is located within the dermis. They may be congenital (e.g., mongolian spot) or acquired.

For each of the seven cases, study the image(s) and then answer the questions. You can click on the image to view a larger version if required.

Each case should take approximately 2 minutes to complete. There is a list of suggested further reading material at the end of the quiz.

Case 1

Blue naevus

Blue naevi are benign dermal tumours that appear during childhood or adult life and then remain stable. They may be flat or elevated and have a smooth surface. Generally solitary, they are most often located on the head and neck, sacral region or dorsum of hands and feet.

Dermoscopy reveals a uniform steel-blue colour, sometimes with central or peripheral brown blotches.

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