title: Comparison of MITF and Melan-A Immunohistochemistry During Mohs Surgery for Lentigo Maligna-Type Melanoma In Situ and Lentigo Maligna Melanoma.
abstract: BACKGROUND
  Mohs micrographic surgery (MMS) with frozen section immunohistochemistry is a treatment option for malignant melanoma in situ (MMIS) and lentigo maligna melanoma (LMM). Melan-A is a cytoplasmic melanocyte immunostain useful on frozen sections but may lack specificity. Microphthalmia transcription factor (MITF) is a more specific nuclear melanocyte immunostain less frequently used in MMS.
  
  
  OBJECTIVE
  To quantify melanocyte density in chronic sun-damaged skin (CSDS), negative margin, and tumor from patients undergoing MMS for MMIS and LMM using MITF and melan-A.
  
  
  METHODS
  Sixteen patients with MMIS or LMM had frozen sections from CSDS, negative margin, and 12 tumor samples, stained with MITF and melan-A. Melanocyte counts were performed.
  
  
  RESULTS
  Chronic sun-damaged skin mean melanocyte count (MMC) for MITF and melan-A was 9.8 and 13.7, respectively, (p < .001). Negative margin MMC for MITF and melan-A was 8.84 and 14.06, respectively, (p < .001). Tumor MMC for MITF and melan-A was 63.5 and 62.4, respectively.
  
  
  CONCLUSIONS
  Although both MITF and melan-A facilitate the identification of tumor during MMS for MMIS and LMM, the apparent melanocyte density on tumor-free CSDS appears higher with melan-A than MITF. Microphthalmia transcription factor provides a crisp outline of melanocyte nuclei and is a useful alternative stain to melan-A for MMS of melanoma.
authors.affiliation: Department of Dermatology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Christensen
authors.forename: Phillip C
authors.initials: PC
authors.lastname: Hochwalt
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Hocker
authors.forename: Randall K
authors.initials: RK
authors.lastname: Roenigk
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Brewer
authors.forename: Christian L
authors.initials: CL
authors.lastname: Baum
authors.forename: Clark C
authors.initials: CC
authors.lastname: Otley
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Arpey
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D002278:Carcinoma in Situ / Q000473:pathology / Q000601:surgery*; D002452:Cell Count; D005260:Female; D005629:Frozen Sections; D006801:Humans; D018327:Hutchinson's Melanotic Freckle / Q000473:pathology / Q000601:surgery*; D007150:Immunohistochemistry; D058965:MART-1 Antigen / Q000032:analysis*; D008297:Male; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000473:pathology / Q000601:surgery*; D051739:Microphthalmia-Associated Transcription Factor / Q000032:analysis*; D008875:Middle Aged; D015580:Mohs Surgery / Q000379:methods*; D012878:Skin Neoplasms / Q000473:pathology / Q000601:surgery*
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; D051739:Microphthalmia-Associated Transcription Factor