title: Frequency of and factors associated with positive or equivocal margins in conventional excision of atypical intraepidermal melanocytic proliferations (AIMP): A single academic institution cross-sectional study.
abstract: BACKGROUND
  No evidence-based surgical guidelines exist for atypical intraepidermal melanocytic proliferation (AIMP), a descriptive histopathologic diagnosis with uncertain malignant potential.
  
  
  OBJECTIVE
  We sought to identify the frequency of and risk factors associated with positive or equivocal margins after conventional excision.
  
  
  METHODS
  We conducted a retrospective cross-sectional study of 413 AIMPs treated by conventional excision.
  
  
  RESULTS
  Positive or equivocal margins were seen in 2.9% (12/413) of conventional excisions of AIMP. Risk factors associated with positive or equivocal margins included anatomic location on the head and neck (5/51, 9.8%; odds ratio 6.91, 95% confidence interval 1.93-24.80) (P = .012) and a preoperative biopsy specimen that included melanoma in situ in the differential diagnosis (11/214, 5.1%; odds ratio 10.73, 95% confidence interval 1.37-83.88) (P = .006). The frequency of positive or equivocal margins did not differ significantly with surgical margins greater than or less than 5 mm (odds ratio 0.61, 95% confidence interval 0.18-2.07) (P = .457).
  
  
  CONCLUSIONS
  This was a single-site, retrospective observational study.
  
  
  CONCLUSIONS
  AIMP has a significantly increased risk for incomplete excision when it is located on the head and neck or has a preoperative histologic differential diagnosis that includes melanoma in situ. These subsets of AIMP may benefit from Mohs micrographic surgery or staged surgical excision to confirm clear margins before reconstruction.
authors.affiliation: Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Junqian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, University of Pennsylvania Health System, Philadelphia, Pennsylvania.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Miller
authors.affiliation: Department of Dermatology, University of Pennsylvania Health System, Philadelphia, Pennsylvania.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Sobanko
authors.affiliation: Department of Dermatology, University of Pennsylvania Health System, Philadelphia, Pennsylvania.
authors.forename: Thuzar M
authors.initials: TM
authors.lastname: Shin
authors.affiliation: Department of Dermatology, University of Pennsylvania Health System, Philadelphia, Pennsylvania. Electronic address: jeremy.etzkorn@uphs.upenn.edu.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Etzkorn
mesh_terms: D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016015:Logistic Models; D008297:Male; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D008875:Middle Aged; D015580:Mohs Surgery / Q000009:adverse effects* / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000473:pathology*; D009366:Neoplasm Seeding; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D016019:Survival Analysis; D055815:Young Adult; D000096142:Cutaneous Malignant Melanoma
keywords: Mohs; atypical intraepidermal melanocytic proliferation; excision; melanoma; positive margin; surgery