PRAME Expression in Recurrent Melanocytic Neoplasms

Summary: Background: Recurrent melanocytic lesions pose diagnostic challenges. In the context of residual melanocytic proliferation and scar, both recurrent nevi and recurrent melanoma may exhibit similar features such as architectural disorder and cytologic atypia. PRAME expression is a sensitive and specific immunohistochemical marker for melanoma. Limited data exist on PRAME expression in recurrent melanocytic neoplasms. This study aims to assess the clinical utility of PRAME in differentiating recurrent nevi from recurrent melanoma. Methods: Cases of recurrent melanocytic neoplasms from January 2021 to August 2024 were identified using institutional SoftPath software and clinical history of associated scar or previous biopsy. Cases were scored on PRAME expression from 0 to 4+ based on the percentage of melanocytes with nuclear expression. Chi-square analysis was performed to compare PRAME expression in recurrent benign nevi versus malignant melanoma. Results: 53 cases fulfilled inclusion criteria (42 recurrent benign nevi, 11 recurrent melanoma). PRAME was significantly more expressed in 6/11 (54.5%) malignant melanoma compared to 1/42 (2.4%) benign nevi (p < 0.001). Conclusion: PRAME expression may have utility in differentiating recurrent nevi from recurrent melanoma. However, while positive PRAME expression strongly supports a malignant recurrent melanocytic neoplasm, negative PRAME expression should be interpreted with caution.