Acral nevus

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Acral nevus, also volar nevus, is a benign melanocytic lesion of the palm or sole.

Melanocytic nevus with intraepidermal ascent of cells (abbreviated MANIAC) redirects to here.

General

Note:

  • Volar refers to the palmar aspect or plantar aspect.[2]

Gross

  • Pigmented lesion.

Note:

  • Should be bisected perpendicular to the dermatoglyphs (ridges).[3]
    • Lesions sectioned parallel to the ridges (on microscopy) may appear to have confluent junctional nests (leading to the diagnosis of melanoma).

Microscopic

Features:

  • Acral skin:
    • Thick stratum corneum (hyperkeratotic).
    • Thick stratum spinosum (acanthotic).
  • Nevus with intraepidermal ascent of cells.
    • May be referred to as Pagetoid scatter.
    • Should not be present at the edge of the lesion - key feature.[3]

Notes:

  • Intraepidermal ascent of cells is usually suggestive of melanoma.
    • In acral sites (esp. at the centre of a lesion) the criteria are relaxed, i.e. this is considered benign for this site.
  • Nests in the ridges raise the suspicion of melanoma.
    • Memory device "ridges are risky, furrows are fine".[3]

DDx:

See also

References

  1. Massi, G.; Vellone, VG.; Pagliarello, C.; Fabrizi, G. (Apr 2009). "Plantar melanoma that mimics melanocytic nevi: a report of 4 cases with lymph node metastases and with review of positive and negative controls.". Am J Dermatopathol 31 (2): 117-31. doi:10.1097/DAD.0b013e318194c904. PMID 19318796.
  2. URL: http://www.medterms.com/script/main/art.asp?articlekey=9907. Accessed on: 14 January 2013.
  3. 3.0 3.1 3.2 Elston, D. (Jul 2012). "Practical advice regarding problematic pigmented lesions.". J Am Acad Dermatol 67 (1): 148-55. doi:10.1016/j.jaad.2012.04.006. PMID 22703907.