Skin melanocytic tumor

Melanocytic tumors on acral skin and nail apparatus

Subungual melanoma (melanoma of the nail apparatus)

Topic Completed: 1 May 2013

Minor changes: 3 November 2020

Copyright: 2002-2021,, Inc.

PubMed Search: Subungual melanoma

Christopher S. Hale, M.D.
Page views in 2020: 1,005
Page views in 2021 to date: 1,319
Cite this page: Hale CS. Subungual melanoma (melanoma of the nail apparatus). website. Accessed November 27th, 2021.
Definition / general
  • Melanoma arising in nail unit
  • Uncommon; difficult to diagnose clinically and pathologically
  • Median age 66 years (Am J Surg 2008;195:244), range 24 to 83
  • Common sites are great toe and thumb
Clinical features
  • Often delay in diagnosis because lesion is attributed to trauma; most (73%) cases are AJCC stage II / III, acral lentiginous subtype (66%) and Clark level IV / V (79%, Am J Surg Pathol 2007;31:1902)
  • Sentinel node metastases in 24%
Case reports
  • Useful for distinction from subungual hemorrhage
  • Features include: Hutchinson sign, longitudinal irregular lines, triangular shape of bands, vascular pattern and ulcerations (Br J Dermatol 2013;168:1224)
Clinical images

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Red, friable, broad based nodule

Ulcer on left middle finger

Microscopic (histologic) description
  • Usually not circumscribed
  • Have prominent lentiginous growth with more single cells than nests, moderate to severe atypia, haphazard and dense pagetoid intradermal spread
  • Also ulceration (33%), tumor infiltrating lymphocytes
Microscopic (histologic) images

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Tumor cells are isolated or in nests

Tumor cells are MelanA+

Differential diagnosis
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