Rethinking Melanocytic Tumors: A Critical Appraisal of the WHO Classification and the Myth of Nevus-to-Melanoma Progression.

INTRODUCTION: The recent WHO classification of melanocytic tumors introduces a refined molecular and histopathological framework suggesting distinct pathways and precursor lesions for all melanoma subtypes. While conceptually appealing, its clinical applicability is increasingly questioned. OBJECTIVES: This review critically examines the transformation theory from benign nevi to melanoma, highlighting inconsistencies between the proposed models and real-life practice. METHODS: Through illustrative cases and key epidemiological evidence, we evaluated the validity of current models proposing intermediate lesions in melanoma development. RESULTS: We argue that most melanomas arise de novo and that the so-called intermediate lesions, such as dysplastic nevi and atypical Spitz tumors, may mimic melanoma but are not true biological precursors. CONCLUSIONS: We propose a simplified, clinically oriented reclassification of melanocytic lesions based on morphologic ambiguity and actual behavior, aiming to guide therapeutic decisions and reduce diagnostic overinterpretation.