In an article on lines of Blaschko,1 the authors referred to a study of pigmentary lines by Selmanowitz and me2 and pointed out that we thought that those lines did not correspond to lines of Blaschko. We did say that in the article; however, after looking at the diagrams provided by Bolognia et al,1 it is clear to me that these pigmentary lines did indeed follow Blaschko lines. Also, this same correction applies to a study by Selmanowitz and me3 on hypopigmented markings in blacks. These pigmentary variations represent a common form of mosaicism most easily visible in dark-skinned people.
In a recent article, Nehal et al4 show that pigmentary mosaicism in certain clinical patterns was associated with extracutaneous abnormal features in 30% of their patients. If one were to study dark-skinned people with pigmentary demarcation lines, mediosternal lines, or hypopigmented chest macules as examples
Krivo JM. How Common Is Pigmentary Mosaicism?. Arch Dermatol. 1997;133(4):527-528. doi:10.1001/archderm.1997.03890400133022