Blue nevi are solitary papules 2 mm to 1 cm in diameter or, less commonly, plaques, with a bluish color. The blue color is secondary to the deep placement of the melanocytes in the skin.
Blue nevi are histologically similar to the Mongolian patch, commonly seen over the sacrum of Asian or African-American children.
Blue nevi do not appear to have a significantly increased risk of malignant transformation.
- Plaque blue nevi are usually excised, as there may be an increased risk of melanoma.