Melanocytic nevi with focal atypical epithelioid cell components: a review of seventy-three cases

J Am Acad Dermatol. 1994 May;30(5 Pt 1):724-9. doi: 10.1016/s0190-9622(08)81502-2.


Background: We report a variant of melanocytic nevus that may be confused with melanoma.

Objective: The purpose of this study is to describe the clinical, histologic, and biologic features of nevi with focal atypical epithelioid cell components (clonal nevi).

Methods: Seventy-three cases were retrieved by reviewing lesions previously diagnosed as clonal, combined, deep penetrating, and inverted type-A nevi. Histologic features were assessed and referring physicians received a questionnaire about the presentation and outcome of each case.

Results: Histologically, all cases had a biphasic pattern characterized by an ordinary nevus that contained a darkly pigmented collection of large distinct epithelioid melanocytes in the superficial dermis. Immunostains identified mutant p53 proteins in 50% of dermal clones (9 of 18) but not in ordinary nevus cells adjacent to the clones. We are not aware of any patient developing a malignant melanoma (mean follow-up 24.5 months), including 41 cases that were initially incompletely excised.

Conclusion: Clonal nevi are a distinct variant of melanocytic nevi and should be distinguished from malignant melanoma arising in a preexisting nevus.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cell Nucleus / ultrastructure
  • Child
  • Child, Preschool
  • Cytoplasm / ultrastructure
  • Dysplastic Nevus Syndrome / pathology
  • Epithelium / pathology
  • Female
  • Follow-Up Studies
  • Humans
  • Infant
  • Male
  • Melanins
  • Melanocytes / pathology
  • Melanoma / pathology
  • Middle Aged
  • Nevus / pathology
  • Nevus, Pigmented / pathology*
  • Prognosis
  • Skin Neoplasms / pathology*


  • Melanins