title: Inner gray halo, a novel dermoscopic feature for the diagnosis of pigmented actinic keratosis: clues for the differential diagnosis with lentigo maligna.
abstract: BACKGROUND
  Pigmented actinic keratosis (PAK) is a frequent simulator of lentigo maligna (LM) on the face upon clinical and dermoscopic examination, leading to misdiagnosis and unnecessary excisions. LM and PAK share dermoscopic features, making it difficult to have a confident diagnosis of PAK only with current dermoscopic knowledge.
  
  
  OBJECTIVE
  We sought to evaluate sensitivity, specificity, and interobserver reproducibility of a novel dermoscopic feature, inner gray halo (IGH), and establish its histopathological and confocal correlations.
  
  
  METHODS
  Dermoscopists blinded to histopathological diagnosis evaluated 58 PAK and 21 LM for the presence of IGH and dermoscopy parameters. Areas exhibiting IGH were marked and imaged with reflectance confocal microscopy before sampling for histopathologic correlation. Reflectance confocal microscopy and transverse histologic sectioning were performed in 14 of 79 cases.
  
  
  RESULTS
  IGH was present in 53 of 58 (94.1%) PAK and in 5 of 21 (23.8%) LM in our series (sensitivity 91.4%; specificity 71.4%; positive predictive value 89.8%). Interobserver agreement was excellent (Kappa 0.846). Through transverse and perpendicular histologic sections, a dermoscopic-histologic-confocal correlation of IGH was established.
  
  
  CONCLUSIONS
  A larger test set is needed to further validate the use of IGH in the differential diagnosis of PAK and facial pigmented lesions.
  
  
  CONCLUSIONS
  IGH is a novel dermoscopic parameter useful for the differentiation of PAK from LM on the face.
authors.affiliation: Department of Dermatology, Federal University of São Paulo, São Paulo, Brazil; Cutaneous Oncology Department, A. C. Camargo Cancer Center, São Paulo, Brazil. Electronic address: maumennas@gmail.com.
authors.forename: Mauricio M
authors.initials: MM
authors.lastname: Nascimento
authors.affiliation: Department of Dermatology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Danielle
authors.initials: D
authors.lastname: Shitara
authors.affiliation: Department of Dermatology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Milvia M S S
authors.initials: MM
authors.lastname: Enokihara
authors.affiliation: Department of Dermatology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Sergio
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pellacani
authors.affiliation: Cutaneous Oncology Department, A. C. Camargo Cancer Center, São Paulo, Brazil.
authors.forename: Gisele G
authors.initials: GG
authors.lastname: Rezze
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D001938:Brazil; D015331:Cohort Studies; D016001:Confidence Intervals; D046169:Dermoscopy / Q000379:methods; D003937:Diagnosis, Differential; D005145:Face; D005260:Female; D006801:Humans; D018327:Hutchinson's Melanotic Freckle / Q000175:diagnosis* / Q000473:pathology / Q000648:ultrastructure; D017495:Hyperpigmentation / Q000175:diagnosis* / Q000473:pathology; D007150:Immunohistochemistry; D055623:Keratosis, Actinic / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D015588:Observer Variation; D011230:Precancerous Conditions / Q000473:pathology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000648:ultrastructure
keywords: confocal; dermoscopy; face; histopathology; lentigo maligna; pigmented actinic keratosis