The Expanding Spectrum of Blue Melanocytic Tumors.

The blue melanocytic tumors represent a wide group of cutaneous pigmented proliferations with important variations in both their clinical and histologic presentations. They are genetically distinct from both common and SPitz naevi with frequent hotspot mutations occuring in members of the G-coupled protein pathway or gene fusions. They clinically appear as papules and nodules with a blue hue related to the Tyndall effect. Herein, we will focus on the recent progress in the molecular field of the blue tumors and describe the clinical, histologic, and genetic features of the vast spectrum of blue naevi and related entities in the skin.