Epidermodysplasia verruciformis-associated eccrine neoplasm: morphologic and immunohistochemical characterization of 25 lesions in two patients.

We analyzed 25 eccrine neoplasms from two patients with hereditary epidermodysplasia verruciformis (EDV), representing the largest series reported to date. All lesions shared a reproducible architecture with multifocal epidermal connections, anastomosing epithelial strands of basaloid-poroid cells, and a myxoid fibrovascular stroma. Additional findings included focal clear cell change and intraepithelial atypia (20% of cases). Immunohistochemically, EMA and CEA confirmed ductal differentiation, while preserved YAP1 and negative NUT staining supported a lineage distinct from conventional poroma. p53 overexpression and diffuse p16 labeling were confined to atypical foci. These findings broaden the morphologic spectrum of this emerging entity and support the use of targeted immunohistochemistry to recognize atypical foci in EDV-associated eccrine neoplasms.