[Becker's nevus associated with epidermal nevus: another example of twin spotting?].
Linear epidermal nevi are believed to be caused by an autosomal dominant lethal mutation that can only be expressed by mosaicism. Becker's nevus can be explained by paradominant inheritance which is only manifested clinically by an acquired loss of heterozygosity. We present the case of a 16-year-old female with an epidermal nevus located on the left side of the neck, and also a Becker's nevus located on the ipsilateral shoulder. It is interesting to speculate that this supposed double mosaicism could be another example of "twin spotting" or non-allelic didymosis, although the possibility that this is a chance association cannot be ruled out, as the lesions are not closely associated.
Rodríguez-Díaz
Eloy
E
Servicio de Dermatología, Hospital de Cabueñes, Gijón, España. eloy1@telecable.espana
Alvarez-Cuesta
César-Cosme
CC
Blanco
Susana
S
Galache
Cristina
C
Hidalgo
Yolanda
Y
D000293:Adolescent; D005260:Female; D006222:Hamartoma / Q000196:embryology / Q000235:genetics*; D006258:Head and Neck Neoplasms / Q000196:embryology / Q000235:genetics*; D006801:Humans; D019656:Loss of Heterozygosity; D009030:Mosaicism; D009508:Nevus, Pigmented / Q000196:embryology / Q000235:genetics*; D012782:Shoulder; D012871:Skin Diseases / Q000196:embryology / Q000235:genetics*; D012878:Skin Neoplasms / Q000196:embryology / Q000235:genetics*