Department of Biochemistry

Introduction: Diagnostic uncertainty for ambiguous lesions that fall on the spectrum between nevi and melanoma remains a significant challenge and can have consequences for patient management. Methods: This study aimed to compare the diagnostic utility of preferentially expressed antigen in melanoma (PRAME) immunohistochemistry to molecular testing (FISH and SNP array) in 34 diagnostically challenging melanocytic lesions and 9 non-diagnostically challenging melanomas. Results: We conclude that while PRAME immunohistochemistry demonstrates high specificity (96.2%) in diagnostically challenging melanocytic lesions, its low sensitivity (12.5%) suggests that it should not replace histopathological evaluation in rendering the final diagnosis. Conclusions: These findings suggest that PRAME may serve as a useful adjunct in the diagnostic workup, particularly due to its high negative predictive value, but should be used in conjunction with other established diagnostic modalities.