Introduction: Epidermal nevi are hamartomas of the epidermis and papillary dermis that are usually present during the first years of life. Rarely, malignant transformations develop in association with epidermal nevi. Few cases have been reported worldwide, however the lifetime risk and incidence are unknown. Case Report: This is a case series about basal cell carcinoma arising on epidermal nevus. The first patient is a 42-year-old Filipino female, who presented with a verrucous plaque at birth on the left temple which then developed multiple, discrete to confluent, grayish, papules and nodules on the surface. Histological examination revealed nevus sebaceus and basal cell carcinoma, pigmented type. The second patient is a 53-year-old Filipino male, who presented with a papillomatous plaque on the left temple since the first year of life which then increased in size along with the presence of a solitary bluish-black macule noted by dermoscopic examination. Histologic examination showed verrucous epidermal nevus and basal cell carcinoma, pigmented type. Conclusion Two rare cases of basal cell carcinoma arising on epidermal nevus are reported. Despite the rarity of malignant transformation on epidermal nevus, any suspicious growth warrants a biopsy. Knowledge of these cases is important for probing suspicious growth over an epidermal nevus that would prompt early treatment before these lesions progress in size making it harder to manage.
epidermal nevus ; nevus sebaceus ; verrucous epidermal nevus ; basal cell carcinoma