QHow is PRAME used in dermatopathology?

Preferentially expressed antigen in melanoma (PRAME) is a tumor-associated antigen found to be expressed in most melanomas and variably in other malignant neoplasms of epithelial, mesenchymal, or hematolymphoid lineage.[1]  Detected via immunohistochemistry in melanocytic skin lesions, most melanocytic melanomas are positive for PRAME expression whereas benign nevi are typically negative. Lezcano et al. report 87% PRAME expression in metastatic melanomas and 90% of primary cutaneous melanomas. PRAME expression is rare in benign nevi and the expression pattern is limited and non-diffuse when observed. [2]

Some studies have examined the use of PRAME for use during Mohs surgery for melanoma in situ marginal assessment. [2,3] Although proof of concept has been reported, there is no protocol justifying its utility as a secondary confirmatory stain for clearance of melanoma in situ lesions. [3] Larger multi-institution studies are needed to determine its utility as a monostain during Mohs surgery.

References:

1. Alomari et al. J Cutan Pathol. 2021
2. Lezcano et al. Am J Surg Pathol. 2018
3. Lohman et al. Am J Dermatopathol. 2024