Acantholytic dyskeratosis occurring within an epidermal nevus.

Area of Science:

• Dermatology
• Histopathology
• Genetics

Background:

• Epidermal nevi are congenital benign tumors of the epidermis.
• Darier disease (DD) is a rare autosomal dominant genodermatosis characterized by dyskeratosis.
• Linear presentations can occur in both conditions, posing diagnostic challenges.

Observation:

• A 25-year-old woman presented with lifelong, flesh-colored, verrucous plaques in a linear distribution along Blaschko lines.
• The lesions enlarged and thickened after age 20.
• Histopathology showed papillomatous epidermis with foci of acantholytic dyskeratosis, including corps ronds and grains, resembling Darier disease.

Findings:

• The patient lacked a family history of Darier disease.
• The early onset and linear Blaschko line distribution favored acantholytic dyskeratotic epidermal nevi (ADEN).
• Absence of epidermolytic hyperkeratosis was noted.

Implications:

• Distinguishing ADEN from localized Darier disease is crucial for accurate diagnosis and management.
• Histopathological findings can overlap, necessitating careful correlation with clinical presentation.
• This case highlights the importance of considering genodermatoses variants in linear epidermal lesions.