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subungual melanoma

melanoma originating under the nail Etiology: - acral lentiginous melanoma Epidemiology: - seen in patients with darker skin tones - 0.7% to 3.5% of all melanoma cases [3] - 1/3 of all melanoma cases in African Americans, Asians, & native Americans [3] - peak incidence in 5th to 7th decades of life Clinical manifestations: - melanonychia of a single nail raises suspicion of subungual melanoma - pigmentation under the nail extending into the proximal nail fold or other adjacent skin (periungual pigmentation or Hutchinson's sign) - diameter of 3 mm or more with variegated borders - a wider diameter of proximal pigmentation than distal pigmentation indicates an expanding lesion - may also present as diffuse nail discoloration of a single nail * images [4] Laboratory: - nail matrix biopsy [1] Differential diagnosis: - longitudinal melanonychia - pigment generally lighter in color - pigment diameter constant - multiple nails often involved - subungual hematoma - history of trauma - pigmentation progresses distally as nail grows out creating a zone of clearing between the proximal nail fold & the pigmentation - surrounding skin changes generally resolve within a few weeks Management: - refer to dermatology

General

acral lentiginous melanoma nail disease

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 16, 17. American College of Physicians, Philadelphia 2012, 2015
  2. Braun RP, Baran R, Le Gal FA, Dalle S, Diagnosis and management of nail pigmentations. J Am Acad Dermatol. 2007 May;56(5):835-47. Epub 2007 Feb 22. PMID: 17320240
  3. Levit EK, Kagen MH, Scher RK, Grossman M, Altman E. The ABC rule for clinical detection of subungual melanoma. J Am Acad Dermatol. 2000 Feb;42(2 Pt 1):269-74 PMID: 10642684
  4. DermNet NZ: Melanoma of nail unit (images) http://www.dermnetnz.org/hair-nails-sweat/melanoma-nailunit.html
  5. Gosselink CP, Sindone JL, Meadows BJ, Mohammadi A, Rosa M. Amelanotic subungual melanoma: a case report. J Foot Ankle Surg. 2009 Mar-Apr;48(2):220-4. PMID: 19232976
  6. Tan KB, Moncrieff M, Thompson JF et al Subungual melanoma: a study of 124 cases highlighting features of early lesions, potential pitfalls in diagnosis, and guidelines for histologic reporting. Am J Surg Pathol. 2007 Dec;31(12):1902-12. PMID: 18043047