Utility of prame ihc staining in the clinical management of pigmented lesions of varying severity

Summary: A survey study was conducted with the objective of assessing the utility of PRAME IHC staining in the clinical management of pigmented lesions of varying levels of severity. Not all melanomas are PRAME positive and benign nevi may also demonstrate PRAME expression. PRAME staining poses significant patient costs, thus determining its clinical utility is warranted. An Epic SlicerDicer search was used to identify all pigmented lesion biopsy specimens with PRAME IHC staining between January 1^st, 2023 and December 31^st, 2023. Pigmented lesion biopsies with PRAME staining were divided into five categories: 1) Invasive melanoma, 2) Melanoma <i>in situ</i>, severely dysplastic nevi 3) Moderately dysplastic nevi 4) Mildly dysplastic nevi 5) Benign nevi. Three cases were chosen from each category. Twelve clinicians provided their clinical management strategy for each case in three passes. The first pass included non-PRAME IHC and H&E stain interpretation and omitted both PRAME staining results and final histopathologic diagnosis, the second pass included PRAME staining results, and the third pass revealed final histopathologic diagnosis. For all lesions, a smaller percent change in excision rate was seen following the addition of PRAME staining results versus the addition of final histopathologic diagnosis. The greatest difference in excision rate percent change was seen in cases describing severely dysplastic nevi (12.5% change following PRAME staining; 67% change following final diagnosis). Interestingly, the addition of PRAME staining and final histopathologic diagnosis in cases describing melanoma did not alter clinical management (100% excision). Our results highlight the limitations of IHC studies interpreted in isolation for benign and dysplastic nevi and suggest that PRAME staining may not offer as much additional information in the clinical management of melanomas. Limitations include sample size and varied physician comfort in making clinical management decisions without final histopathologic diagnosis. Robyn Guo¹, Jennifer Crimmins³, Suephy Chen² 1. Duke University School of Medicine, Durham, NC, United States. 2. Dermatology, Duke Health, Durham, NC, United States. 3. Pathology, Duke Health, Durham, NC, United States. Pigmentation, Melanoma, and Melanoma Immune Surveillance