title: Cross-sectional analysis of the dermoscopic patterns and structures of melanocytic naevi on the back and legs of adolescents.
abstract: BACKGROUND
  Junctional (flat) naevi predominate on the extremities, whereas dermal (raised) naevi are found primarily on the head, neck and trunk. Few studies have investigated the anatomical site prevalence of melanocytic naevi categorized using dermoscopy.
  
  
  OBJECTIVE
  To identify the prevalence of dermoscopic patterns and structures of naevi from the back and legs of adolescents.
  
  
  METHODS
  Dermoscopic images of acquired melanocytic naevi were obtained from the back and legs of students from a population-based cohort in Framingham, Massachusetts. Naevi were classified into reticular, globular, homogeneous or complex dermoscopic patterns. Multinomial logistic regression modelling assessed the associations between dermoscopic pattern and anatomical location.
  
  
  RESULTS
  In total 509 participants (mean age 14 years) contributed 2320 back naevi and 637 leg naevi. Compared with homogeneous naevi, globular and complex naevi were more commonly observed on the back than the legs [odds ratio (OR) 29·39, 95% confidence interval (CI) 9·53-90·65, P < 0·001 and OR 6·8, 95% CI 2·7-17·14, P < 0·001, respectively], whereas reticular lesions were less likely to be observed on the back than on the legs (OR 0·67, 95% CI 0·54-0·84, P = 0·001). Naevi containing any globules were more prevalent on the back than on the legs (25% vs. 3·6%, P < 0·001). Naevi containing any network were more prevalent on the legs than on the back (56% vs. 40·6%, P < 0·001).
  
  
  CONCLUSIONS
  These findings add to a robust body of literature suggesting that dermoscopically defined globular and reticular naevi represent biologically distinct naevus subsets that differ in histopathological growth pattern, age- and anatomical-site-related prevalence, molecular phenotype and aetiological pathways.
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: M
authors.initials: M
authors.lastname: Fonseca
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: M A
authors.initials: MA
authors.lastname: Marchetti
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: E
authors.initials: E
authors.lastname: Chung
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: S W
authors.initials: SW
authors.lastname: Dusza
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: M E
authors.initials: ME
authors.lastname: Burnett
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: A A
authors.initials: AA
authors.lastname: Marghoob
authors.affiliation: Harvard School of Public Health, Social and Behavioral Sciences, Boston, MA, U.S.A.
authors.forename: A C
authors.initials: AC
authors.lastname: Geller
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: M
authors.initials: M
authors.lastname: Bishop
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.|Department of Dermatology, Sheba Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Scope
authors.affiliation: Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 16 E. 60 Street, New York, NY 10022, U.S.A.
authors.forename: A C
authors.initials: AC
authors.lastname: Halpern
mesh_terms: D000293:Adolescent; D001415:Back; D003430:Cross-Sectional Studies; D046169:Dermoscopy / Q000379:methods; D005260:Female; D006200:Hair Color / Q000502:physiology; D006801:Humans; D007866:Leg; D008137:Longitudinal Studies; D008297:Male; D009508:Nevus, Pigmented / Q000208:ethnology / Q000473:pathology*; D011446:Prospective Studies; D044469:Racial Groups / Q000208:ethnology; D012878:Skin Neoplasms / Q000208:ethnology / Q000473:pathology*; D012880:Skin Pigmentation / Q000502:physiology