title: Differentiating neurotized melanocytic nevi from neurofibromas using Melan-A (MART-1) immunohistochemical stain.
abstract: BACKGROUND
  Neurotized melanocytic nevi and neurofibromas are common, benign cutaneous neoplasms. Usually they are histologically distinct from each other; however, neurotized melanocytic nevi and neurofibromas can be clinically and histologically similar.
  
  
  OBJECTIVE
  To determine whether Melan-A (MART-1) immunohistochemical stain is sufficient to differentiate neurotized melanocytic nevi from neurofibromas.
  
  
  METHODS
  Forty-nine consecutive specimens of melanocytic nevi with neurotization and 49 specimens of neurofibromas were selected. We used antibodies against Melan-A, S100, and neurofilament protein.
  
  
  RESULTS
  All of the melanocytic nevi showed Melan-A staining within the neurotized areas, with most of the areas staining strongly positive, whereas all the neurofibromas were completely absent of Melan-A stain. All of the nevi, including the neurotized areas, stained strongly and diffusely for S100, whereas all the neurofibromas showed a distinctive, sharp, wavy pattern of S100 staining. Neurofilament protein showed scattered staining of both melanocytic nevi and neurofibromas.
  
  
  CONCLUSIONS
  Our data indicate that Melan-A immunohistochemical staining is helpful in differentiating neurotized melanocytic nevi from neurofibromas when distinction on histomorphology alone is difficult.
authors: Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, USA.
authors: Yumei
authors: Y
authors: Chen
authors: Paul W
authors: PW
authors: Klonowski
authors: Anne C
authors: AC
authors: Lind
authors: Dongsi
authors: D
authors: Lu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D058965:MART-1 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009455:Neurofibroma / Q000175:diagnosis* / Q000378:metabolism; D009508:Nevus, Pigmented / Q000175:diagnosis* / Q000378:metabolism; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen