title: Evaluation of the role of routine melan-A immunohistochemistry for exclusion of microinvasion in 120 cases of lentigo maligna.
abstract: BACKGROUND
  To assess the usefulness of routine melan-A immunohistochemistry (IHC) for exclusion of microinvasion in lentigo maligna (LM).
  
  
  METHODS
  One hundred and twenty cases of LM from our archives were reviewed by 2 authors with S100 protein and melan-A IHC using a red chromogen.
  
  
  RESULTS
  Melan-A was useful to confirm the diagnosis of LM in early lesions and to differentiate these from chronically sun-damaged skin. The presence of scattered melan-A-positive cells was noted in the dermis in 72 of 120 cases (melanophages in 36 cases, nonspecific cells different to melanophages in 16 cases, and a dual cell population in 20 cases). The significance of these cells was uncertain. Only 3 cases suspicious for microinvasion were identified: 2 on haematoxylin and eosin and 1 on S100.
  
  
  CONCLUSIONS
  We recommend use of melan-A to confirm the diagnosis in early lesions of LM and in the differential diagnosis from melanocytic hyperplasia in chronically sun-exposed skin. We do not recommend routine use of melan-A to identify or exclude microinvasion. However, it may have a role, in conjunction with S100, in cases with suspicious features for early invasion on haematoxylin and eosin sections.
authors.affiliation: *Department of Dermatology, Basildon University Hospital, Essex, United Kingdom; and †Department of Dermatopathology, St John's Institute of Dermatology, St Thomas' Hospital, London, United Kingdom.
authors.forename: Ravi
authors.initials: R
authors.lastname: Suchak
authors.forename: Omair Akhtar
authors.initials: OA
authors.lastname: Hameed
authors.forename: Alistair
authors.initials: A
authors.lastname: Robson
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D006801:Humans; D018327:Hutchinson's Melanotic Freckle / Q000175:diagnosis*; D007150:Immunohistochemistry; D058965:MART-1 Antigen / Q000032:analysis / Q000096:biosynthesis*; D012878:Skin Neoplasms / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; C548667:MLANA protein, human