Skin - Melanocytic tumor
Other pigmented lesions and disorders of pigmentation
General

Author: Christopher Hale, M.D. (see Authors page)

Revised: 24 February 2017, last major update March 2013

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Pigmented lesions disorders pigmentation general

Cite this page: Other pigmented lesions and disorders of pigmentation - General. PathologyOutlines.com website. http://pathologyoutlines.com/topic/skintumormelanocyticgeneralothermelanocytic.html. Accessed July 26th, 2017.
Definition / general
  • Often only part of lesion is excised and pathologist report includes recommendation for complete excision (J Clin Pathol 2004;57:1121)
Patterns of Benign Behavior
  • Lentiginous hyperplasia (single cell melanocytic growth along dermoepidermal junction)
  • Nested proliferation
  • Melanocyte nuclei are smaller than adjacent keratinocytes
  • Pagetoid proliferation (discohesive single cell growth throughout entire epidermis) is nonspecific; present in Spitz nevi, acral nevi, melanoma (Am J Surg Pathol 1995;19:792)
Other Benign Features
  • Symmetric pattern of growth and involution
  • Lateral dimension of dermal component should roughly equal that of original epidermal component ("shoulder" = when epidermal component extends laterally beyond dermal)
Maturation
  • Deeper portion of lesion has smaller cells with less pigment, less atypia
  • Deep cells grow in smaller sized nests or single cells
  • May resemble neural tissue
  • Maturation is a morphologic term; does not truly reflective biologic maturation (Am J Dermatopathol 1988;10:20)
Case reports