ABSTRACT
The concept of mosaicism has been used to explain different cutaneous patterns, such as the lines of Blaschko, the checkerboard pattern, the phylloid pattern, and a patchy pattern. Many mosaic patterns are caused by loss of heterozygosity, the genetic mechanism by which a heterozygous somatic cell becomes either homozygous or hemizygous. A particular form of loss of heterozygosity is twin spotting, which give rise to two contrary homozygous daughter cells. The concept of twin spotting has been used for some of these human phenotypes, which are characterized by the co-occurrence of two different nevi, including nevus vascularis mixtus. Nevus vascularis mixtus is a rare vascular malformation characterized by the coexistence of a nevus anemicus and a nevus telangiectaticus, and can be associated with extra-cutaneous anomalies, such as cerebral malformations. Herein, we report a 6-year-old girl with paired cutaneous vascular nevi telangiectaticus, anemicus, and nevus vascularis mixtus, that were distributed on the left side of her chest and left arm, without other systemic and neurologic anomalies.