title: Dermatoscopy of flat pigmented facial lesions: diagnostic challenge between pigmented actinic keratosis and lentigo maligna.
abstract: BACKGROUND
  The similarity between clinical pictures of pigmented actinic keratosis (PAK) and lentigo maligna (LM) is well known.
  
  
  OBJECTIVE
  To investigate the frequency of dermatoscopic findings suggestive of LM/lentigo maligna melanoma (LMM) in the other facial pigmented skin lesions (FPSL) and to assess the distinguishing dermoscopic criteria of PAK and LM.
  
  
  METHODS
  Eighty-nine FPSL were evaluated with conventional dermatoscopy. The lesions showing one or more dermatoscopic features considered as specific patterns for the diagnosis of LM/LMM, mainly slate-grey to black dots and globules, slate-grey areas, annular-granular pattern, asymmetrical pigmented follicular openings, black blotches, rhomboidal structures, hyperpigmented rim of follicular openings, slate-grey streaks and dark streaks, were included in the study selectively.
  
  
  RESULTS
  PAK was diagnosed in 67, LM or LMM in 20 and lichen planus-like keratosis in two lesions, histopathologically. Eleven essential dermatoscopic features were observed in facial PAK: slate-grey dots (70%); annular-granular pattern (39%); rhomboidal structures (36%); pseudonetwork (36%); black globules (34%); slate-grey globules (33%); black dots (30%); asymmetrical pigmented follicular openings (25%); hyperpigmented rim of follicular openings (21%); slate-grey areas (18%); and streaks (3%).
  
  
  CONCLUSIONS
  PAK has a striking similarity to LM/LMM in clinical and dermatoscopic features, thus representing a diagnostic challange. All dermatoscopic findings except black blotches were observed in PAK. As dermatoscopic diagnosis of a pigmented skin lesion cannot be based on the presence of a single criterion, we may conclude that histopathology still remains the gold standard for correct diagnosis.
authors.affiliation: Departments of Dermatology Pathology, University of Ankara School of Medicine, Samanpazari 06100, Ankara, Turkey. nisaakay15@yahoo.com
authors.forename: B N
authors.initials: BN
authors.lastname: Akay
authors.forename: P
authors.initials: P
authors.lastname: Kocyigit
authors.forename: A O
authors.initials: AO
authors.lastname: Heper
authors.forename: C
authors.initials: C
authors.lastname: Erdem
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D046169:Dermoscopy; D003937:Diagnosis, Differential; D005145:Face / Q000473:pathology; D005148:Facial Dermatoses / Q000473:pathology*; D005260:Female; D006801:Humans; D018327:Hutchinson's Melanotic Freckle / Q000473:pathology*; D055623:Keratosis, Actinic / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012878:Skin Neoplasms / Q000473:pathology*; D055815:Young Adult