Nevus trichilemmocysticus: report of a new case of a recently recognized entity.

A new type of organoid epidermal nevus, characterized by the presence of multiple trichilemmal cysts disposed in a linear arrangement, was recently recognized and named nevus trichilemmocysticus. We report a 10-year-old girl with a congenital linear dermatosis affecting the head, neck, trunk, limbs, palms, and soles. Initially, the lesions that followed the lines of Blaschko consisted of yellowish plaques covered by verrucous papules and filiform hyperkeratoses. Additionally, since the age of 6 years, numerous cyst-like structures developed on the linear lesions involving the limbs. On histopathological examination, all of the excised cystic lesions were found to be trichilemmal cysts. Hence, we herein describe a new case of nevus trichilemmocysticus.