title: Congenital melanocytic nevi and nevus spilus have a tendency to follow the lines of Blaschko: an examination of 200 cases.
abstract: There have been few reports about the characteristics of the pigmentary arrangement of congenital melanocytic nevi (CMN) and nevus spilus (NS). Though the lines of Blaschko, which don't correspond to other lines such as Langer's lines and skin dermatomes, are well known to be followed by some rare pigmentary disorders, the relationship between these two disorders and the lines of Blaschko has not been discussed. Therefore, through an examination of 200 cases, we investigated whether or not the arrangement of CMN and NS follow the lines of Blaschko. Thirty-nine out of 92 cases (42.4%) of CMN and 67 out of 108 cases (62.0%) of NS were considered to follow the lines of Blaschko. Today, the idea is widely accepted that two functionally different cells proliferate during early embryogenesis of the skin which is caused from mosaicism and, as a result, the lines of Blaschko appear visually. In our results, we found that there were some cases of CMN and NS which showed a relationship with the lines of Blaschko, which is meaningful considering that the lesions and the lines are both related to pigmentary gene anomalies. The result was compared with CMN and NS by the chi(2) test. NS showed a predominant tendency to follow the lines with a significant difference (P = 0.0055). This may indicate that the lines of Blaschko reflect more clearly the proliferation of the epidermal cells than other cells in growth of the skin of the embryo. Further studies are required to elucidate the reason why some cases follow these lines and others do not.
authors.affiliation: Department of Plastic Surgery, Kobe University Graduate School of Medicine, Kobe City, Japan. hana46@med.kobe-u.ac.jp
authors.forename: Hiromi
authors.initials: H
authors.lastname: Hanayama
authors.forename: Hiroto
authors.initials: H
authors.lastname: Terashi
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Hashikawa
authors.forename: Shinya
authors.initials: S
authors.lastname: Tahara
mesh_terms: D006801:Humans; D009508:Nevus, Pigmented / Q000151:congenital / Q000473:pathology*; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000151:congenital / Q000473:pathology*