Abstract

Malignant transformation is known to occur with many nevi, such as sebaceous nevus. However, cases of secondary tumors developing in verrucous epidermal nevus (VEN) are rare and limited to case reports in the literature. We present three unusual cases of syringocystadenoma papilliferum (SCAP), syringiofibroadenoma, trichilemmoma, and/or basal cell carcinoma (BCC) arising in VEN. The first case is a 40-year-old female who presented with a hyperpigmented and Blaschkoidian verrucal plaque extending from the mons pubis to left lateral thigh since 2 years old. Histologic sections demonstrated hyperkeratosis, papillomatosis, and hypergranulosis of the epidermis consistent with VEN. The lesion also showed areas of syringiofibroadenoma, SCAP, and BCC. The second case is a 31-year-old male with VEN present since birth on the left axilla, trunk, and buttock. Over the years, the patient noticed several bothersome hypertrophic/verrucous pink nodules growing at different sites of the VEN. Microscopic evaluation of these lesions demonstrated characteristic features of SCAP and trichilemmoma. The third case is a 29-year-old female with VEN present at the left knee and right groin area. The patient noticed a small flesh colored-papule on their left knee VEN that became painful. Upon excision of this lesion, the diagnosis of trichilemmoma was made.The occurrence of epithelial/ adnexal tumors in epidermal nevi is very rare, and it remains elusive whether these lesions are clonally related or represent a simple collision of independent tumors. We bring to attention the importance of considering secondary neoplasms occurring in the setting of VEN, which necessitates regular patient follow-up.