Blaschko lines and other patterns of cutaneous mosaicism

Area of Science:

• Dermatology
• Genetics
• Pathology

Background:

• Blaschko lines are a classic pattern of cutaneous mosaicism.
• This pattern is observed in various congenital and acquired skin disorders.
• Other mosaicism patterns include blocklike, phylloid, and lateralization.

Purpose of the Study:

• To review the clinicopathologic spectrum of skin lesions following Blaschko lines.
• To discuss other patterns of mosaicism.
• To highlight differential diagnoses and genetic concepts related to mosaic skin lesions.

Main Methods:

• Review of clinicopathologic spectrum of skin lesions.
• Discussion of differential diagnoses and categorization clues.
• Illustration of genetic concepts with clinical examples.

Main Results:

• Blaschko lines present a classic pattern in various skin disorders.
• Four additional mosaicism patterns are described: blocklike, phylloid, large patches without midline separation, and lateralization.
• Associated findings include inflammatory, hypopigmented, and hyperpigmented lesions in a mosaic distribution.

Conclusions:

• Understanding Blaschko lines and other mosaicism patterns is crucial for diagnosing diverse skin conditions.
• The review emphasizes differential diagnoses and genetic underpinnings of these conditions.
• Clinical examples elucidate genetic concepts like X-chromosome mosaicism and twin spotting.