title: Prevalence of skin lesions in familial adenomatous polyposis: a marker for presymptomatic diagnosis?
abstract: OBJECTIVE
  Benign skin tumors such as lipomas, fibromas, and epidermal cysts are among the extracolonic manifestations of familial adenomatous polyposis (FAP). Readily detectable by inspection, they could serve as presymptomatic diagnostic markers to identify FAP patients. We therefore prospectively determined the prevalence of cutaneous lesions in genetically confirmed adenomatous polyposis coli (APC) mutation carriers and assessed their potential usefulness in the identification of FAP patients.
  
  
  METHODS
  Whole-skin examination was performed in 56 adult APC mutation carriers, compared with a control group (n = 116). In addition, FAP patients were investigated for the presence of congenital hypertrophy of the retinal pigment epithelium (CHRPE), an established clinical marker for FAP, and a detailed review of medical records was performed.
  
  
  RESULTS
  Nearly half of all FAP patients (48.2%) had at least one FAP-associated skin lesion, compared with one third (34.5%) of controls. Only multiple lipomas and combined skin lesions were significantly more prevalent in APC mutation carriers. CHRPE was observed in 22 (43.1%) of 51 FAP patients, including 14 (37.8%) of 37 individuals with APC mutations outside the CHRPE-associated region between codons 311 and 1465.
  
  
  CONCLUSIONS
  Despite a significantly higher prevalence of multiple lipomas, occurring at younger age, and combined skin lesions in APC mutation carriers, the low diagnostic sensitivity of FAP-associated skin lesions precludes their use as markers for FAP in clinical practice. Based on our findings, the common CHRPE-associated region should be extended to APC codons 148-2043.
authors.affiliation: Research Group of Dermatology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland. burgerb@uhbs.ch
authors.forename: Bettina
authors.initials: B
authors.lastname: Burger
authors.forename: Nadja
authors.initials: N
authors.lastname: Cattani
authors.forename: Swantje
authors.initials: S
authors.lastname: Trueb
authors.forename: Rosaria
authors.initials: R
authors.lastname: de Lorenzo
authors.forename: Mauro
authors.initials: M
authors.lastname: Albertini
authors.forename: Emanuele
authors.initials: E
authors.lastname: Bontognali
authors.forename: Christoph
authors.initials: C
authors.lastname: Itin
authors.forename: Nathalie
authors.initials: N
authors.lastname: Schaub
authors.forename: Peter H
authors.initials: PH
authors.lastname: Itin
authors.forename: Karl
authors.initials: K
authors.lastname: Heinimann
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D000328:Adult; D016022:Case-Control Studies; D004814:Epidermal Cyst / Q000150:complications / Q000175:diagnosis; D005260:Female; D005350:Fibroma / Q000150:complications / Q000175:diagnosis; D017491:Genes, APC; D006579:Heterozygote; D006801:Humans; D008067:Lipoma / Q000150:complications / Q000175:diagnosis; D008297:Male; D010857:Pigment Epithelium of Eye / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012164:Retinal Diseases / Q000150:complications / Q000151:congenital; D012878:Skin Neoplasms / Q000150:complications / Q000175:diagnosis*