Eccrine Poroma Arising within Nevus Sebaceous.

Nevus sebaceous is a congenital, benign hamartomatous lesion, characterized by a yellowish to skin-colored, hairless, verrucous plaque on the head and neck region. In later life, a secondary tumor, either benign or malignant, can develop within nevus sebaceous. Eccrine poroma developing on nevus sebaceous is extremely rare. There are few case reports of eccrine poroma developing within nevus sebaceous. We report a case of a 30-year-old female who presented with a congenital, hairless, verrucous, yellowish lesion on the scalp and an erythematous nodule arising within the yellowish lesion for 8 months. Her clinical presentation and histopathological findings were compatible with nevus sebaceous and eccrine poroma.