ABSTRACT
Spitz nevi are acquired melanocytic lesions with a wide histomorphological spectrum. Different histological variants are observed, including hyalinized, polypoid, desmoplastic, angiomatoid and halo Spitz nevus. The halo phenomenon presents as a border of depigmentation (vitiligo-like) around a melanocytic nevus, and it can also be seen in Spitz nevi, even if it is an uncommon phenomenon. Typically, it is observed in young adults, and the back is the most commonly affected site. The histologic correlate is regression of the underlying nevus. The nevus is infiltrated by an admixture of CD8+ cytotoxic T cells, CD4+ T-helper (Th) cells, macrophages and Langerhans cells. B cells may also be seen in between the nests of nevus cells. With evolution of the lesion, the number of nevus cells diminishes through the effects of cytotoxic T cells.
