Skin melanocytic tumor

Lentigines, melanotic macules and melanocytic hyperplasia

Melanocytic hyperplasia

Last author update: 1 March 2013
Last staff update: 8 November 2021

Copyright: 2002-2023,, Inc.

PubMed Search: atypical melanocytic hyperplasia

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Melanocytic hyperplasia. website. Accessed March 21st, 2023.
Definition / general
  • Also called atypical melanocytic proliferation or benign atypical junctional melanocytic hyperplasia
Case reports
Microscopic (histologic) description
  • Atypical single unit melanocytes limited to epidermis, often seen at periphery of classic melanoma
  • In contrast to melanoma in situ, exhibits only focal confluence at dermoepidermal junction, has limited pagetoid spread and involves only upper hair follicle
  • Factors favoring atypical melanocytic hyperplasia over melanoma in situ (Mod Pathol 2000;13:857):
    • No lateral spread
    • No upward extension into epidermis
    • No finely granular, "smoky" melanin
    • No marked cytologic atypia
    • No mitotic figures
    • No host inflammatory fibrotic response
Differential diagnosis
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