[Congenital linear nevus sebaceus].

Area of Science:

• Dermatology
• Pathology
• Genetics

Background:

• Nevus sebaceous is a congenital hamartoma typically affecting the head and neck.
• Blaschko lines represent patterns of somatic mosaicism, often seen in various dermatoses.

Observation:

• An unusual case of nevus sebaceous presented as a linear, papulovesicular lesion along the Blaschko lines on the lower extremity.
• The clinical presentation mimicked other conditions such as incontinentia pigmenti or infection.

Findings:

• Biopsy confirmed the diagnosis of nevus sebaceous, despite its atypical location and morphology.
• The lesion's linear arrangement followed Blaschko lines, suggesting a mosaic pattern of development.

Implications:

• Recognizing atypical presentations of nevus sebaceous is crucial for accurate diagnosis.
• This case underscores the need for careful differential diagnosis to prevent unnecessary investigations and treatments for patients.