A blue naevus (nevus) is a rather unusual but non-cancerous mole.
The blue naevus is a dark blue colour because the pigment cells (melanocytes) are deeper in the skin than in commoner brown moles and freckles. Characteristically, the view seen with dermoscopy is a uniform steel-blue pattern.
Blue nevi may be found anywhere on the body. They usually appears on the skin of older children and teenagers, but may develop at any age. They are harmless.
No treatment is needed as blue naevi are harmless. However, some people with a blue naevus on an exposed part of the body ask for it to be removed for cosmetic reasons. If the lesion has only recently appeared, your doctor may to prefer to remove it to make sure it is not a dangerous skin cancer, malignant melanoma.