Abstract

Background:
Preferentially Expressed Antigen in Melanoma (PRAME) is an immunohistochemical stain used to differentiate benign and malignant melanocytic neoplasms. However, significant variability in expression within benign nevi may complicate its utility. Spitzoid melanocytic neoplasms pose a well-documented diagnostic challenge, and the current understanding of PRAME expression in Spitz nevi is limited. Several studies suggest that PRAME expression may be higher in Spitz nevi than in other benign melanocytic nevi. This study aims to characterize the expression of PRAME in various subsets of Spitz nevi, including conventional Spitz, pigmented spindle cell nevus of Reed, desmoplastic Spitz, and pagetoid Spitz.

Methods:
We conducted a retrospective review of all patients aged 18 and older with a histopathologic diagnosis of a Spitz nevus from April 1, 2017, to April 1, 2024. Cases were subjected to PRAME and classified from 0 to 4+. The 4+ designation, considered a positive result, indicates that 76% or more of the cells displayed positive staining.

Results and Conclusions:

PRAME staining in Spitz nevi will be characterized.