Skin melanocytic tumor
Melanoma
Subungual melanoma (melanoma of the nail apparatus)


Topic Completed: 1 May 2013

Revised: 16 May 2019

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

PubMed Search: Subungual melanoma

Christopher S. Hale, M.D.
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Page views in 2019 to date: 723
Cite this page: Hale CS. Subungual melanoma (melanoma of the nail apparatus). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumormelanocyticsubungualmelanoma.html. Accessed September 17th, 2019.
Definition / general
  • Melanoma arising in nail unit
Epidemiology
  • Uncommon; difficult to diagnose clinically and pathologically
  • Median age 66 years (Am J Surg 2008;195:244), range 24 to 83
Sites
  • 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
Treatment
Dermoscopy
  • 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

Images hosted on other servers:

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

Images hosted on other servers:

Tumor cells are isolated or in nests

Tumor cells are MelanA+

Differential diagnosis
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