title: Skeletal changes in epidermal nevus syndrome: does focal bone disease harbor clues concerning pathogenesis?
abstract: Epidermal nevus syndrome (ENS) is a rare, sporadic, congenital disorder of unknown etiology featuring a complex and highly variable phenotype that can include focal or generalized skeletal disease. We describe a young man with ENS manifesting right-sided linear skin lesions, generalized weakness, diffuse osteopenia associated with hypophosphatemic rickets, and distinctive focal bone lesions ipsilateral to the skin findings. Review of the literature concerning ENS-associated skeletal disease suggested such focal bone defects are fibrous dysplasia, but our patient did not have the typical radiographic or histopathologic findings of fibrous dysplasia. Nevertheless, his circulating fibroblast growth factor 23 (FGF-23) level was elevated, likely functioning as a "phosphatonin," yet no activating mutations in GNAS previously reported in fibrous dysplasia or McCune-Albright syndrome were detected in his leukocytes or affected skin. We postulate that the focal skeletal disease, although different than fibrous dysplasia, may be a source of FGF-23 in ENS.
authors.affiliation: Department of Pediatrics, Children's Craniofacial Center, University of Washington and Children's Hospital and Regional Medical Center, Seattle, Washington 98105-5371, USA. cheike@u.washington.edu
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Heike
authors.forename: Michael L
authors.initials: ML
authors.lastname: Cunningham
authors.forename: Robert D
authors.initials: RD
authors.lastname: Steiner
authors.forename: Deborah
authors.initials: D
authors.lastname: Wenkert
authors.forename: Robin L
authors.initials: RL
authors.lastname: Hornung
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Gruss
authors.forename: Francis H
authors.initials: FH
authors.lastname: Gannon
authors.forename: William H
authors.initials: WH
authors.lastname: McAlister
authors.forename: Steven
authors.initials: S
authors.lastname: Mumm
authors.forename: Michael P
authors.initials: MP
authors.lastname: Whyte
mesh_terms: D000293:Adolescent; D000328:Adult; D001847:Bone Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000089703:Fibroblast Growth Factor-23; D006801:Humans; D008297:Male; D009506:Nevus / Q000150:complications / Q000503:physiopathology*; D013577:Syndrome; D014057:Tomography, X-Ray Computed