Observational Study Examining the Diagnostic Practice of Ki67 Staining for Melanocytic Lesions

Nikki S. Vyas, Ahmad Charifa, Garrett T. Desman, Matthew Goldberg, Rajendra Singh, Robert G. Phelps, Jennifer M. McNiff

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Background:Dermatopathologists routinely use Ki67 immunostaining to assess atypical melanocytic lesions with a dermal component to determine whether an ambiguous tumor is melanoma. However, there is no universal standard of use for Ki67 in melanocytic neoplasms. We sought to observe the real-world use of Ki67 in the diagnosis of melanocytic lesions and establish a best practice recommendation.Methods:We searched dermatopathology reports from 2 academic practices for melanocytic lesions in which Ki67 staining was used for diagnosis. The proliferation rate was compared between cases diagnosed as benign (not requiring re-excision), moderate to severely dysplastic or atypical Spitz nevi (requiring re-excision), and malignant melanoma. The use of other melanocytic markers and consensus review was also recorded and compared between institutions.Results:Pathology reports for 106 cases were reviewed. A high Ki67 proliferation rate (n = 18) favored a diagnosis of melanoma or nevi requiring re-excision (15/18, 83.3%) versus a benign nevus (3/18, 16.67%). A high Ki67 rate was 71.4%-90.9% sensitive and 40%-56% specific for the diagnosis of nevus requiring re-excision or melanoma. Institutional practices differed in regard to reporting of Ki67 staining, the use of multiple markers in the workup of atypical melanocytic lesions (HMB45, Melan-A, Ki67 being most common), and consensus review.Conclusions:A negative or low Ki67 proliferation rate correlates well with rendering of a benign diagnosis. However, a low proliferation rate does not preclude the diagnosis of melanoma. Ki67 staining is most commonly used as an ancillary test to support a diagnosis after other factors have been considered, such as histopathologic morphology and results of additional concurrently used stains.

Original languageEnglish
Pages (from-to)488-491
Number of pages4
JournalAmerican Journal of Dermatopathology
Volume41
Issue number7
DOIs
StatePublished - 1 Jul 2019

Keywords

  • Ki67
  • melanocytic
  • melanoma
  • nevus

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