1. nevus, blue Usually a benign tumor, that commonly presents as a solitarybluenodule with spindled MELANOCYTES covered by smoothSKIN. Several variants have been identified, one variantbeing malignant. The bluecolor is caused by large, densely packed melanocytes deep in the DERMIS of the nevus. In CHILDREN, they usually occur on the BUTTOCKS and LUMBOSACRAL REGION and are referred to as cellular blue nevi. Malignant blue nevi are more commonly found on the SCALP.