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

  • Palms or soles.
  • May be confused with malignant melanoma.[1]
    • >45 years old with a "compound nevus"... consider melanoma.[1]

Note:

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

Gross

  • Pigmented lesion - usually small.

Grossing 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).

Image

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]
  • Large (diameter) lesions (>10 mm) should prompt consideration of melanoma.[1]
  • Depth >1 mm should prompt consideration of melanoma.[1]

DDx:

Sign out

Lesion, Sole of Left Foot, Excision:
     - Benign acral compound nevus.

Alternate

Skin Lesion, Plantar Aspect Left Foot, Excision: 
- Benign compound nevus, completely excised. 

Micro

The sections show melanocytes predominantly in the superficial dermis. Rare melanocytic nests are seen at the dermal-epidermal junction. There is no pagetoid spread of melanocytes in the epidermis at the edge of the lesion. The lesion is symmetrical in its architecture. Superficially, melanocytes are in nests and pigment is present. The melanocytes mature with depth. No mitotic activity is appreciated. The lesion is clear of the margin (clearance ~ 3 mm).

See also

References

  1. 1.0 1.1 1.2 1.3 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.