Polypoid Spitz Nevus With a Halo Reaction.

Approximately, 2% of Spitz nevi are polypoid; between 3.6% and 7.4% present with a halo reaction. In tandem, these low percentages make the presence of a polypoid Spitz nevus with a halo reaction uncommon; we have not found reports of any previous cases. In the current report, we present a polypoid Spitz nevus with a halo reaction on the back of a 10-year-old male and discuss the morphologic findings. The lesion showed preserved nuclear expression of BAP1. There was no immunohistochemical expression of BRAF and ALK, while the melanocytic cells expressed p16. Comparative genomic hybridization was performed, and no significant aberrations were found. Only 2 small losses were evidenced in chromosome 8. The patient has been followed now for 2 years with no recurrence.