Skin melanocytic tumor
Other pigmented lesions and disorders of pigmentation
General


Topic Completed: 1 March 2013

Revised: 4 April 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Pigmented lesions disorders pigmentation general

Christopher S. Hale, M.D.
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Cite this page: Hale C Other pigmented lesions and disorders of pigmentation - General. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumormelanocyticgeneralothermelanocytic.html. Accessed August 19th, 2019.
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
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