Melanocytic nevus

Last Updated: 2022-03-25

Author(s): Anzengruber F., Navarini A.

ICD11: 2F20.Z

Mother's mark, nevus cell naevus, naevus naevocellularis, nevocyte naevus.

Congenital or acquired, melanocytic skin change. It is a hamartoma.

  • More common in Caucasians than in Asians
  • Rarely occurring or barely visible in Africans due to pigmentation

Dermal melanocytosis

  • Naevus bleu
  • Mongolian spot
  • Naevus Ota (head, also called nevus fuscocoeruleus ophtalmomaxillaris)
  • Naevus Ito (shoulders, "inferior", also called nevus fuscocoeruleus deltoideoacromialis

Congenital nevi

  • Small congenital nevus cell nevi (< 3cm)
  • Large congenital nevus cell naevi (> 3cm) --> from 3 cm or from 20 satellites or both, extended work-up including MRI should be performed.
  • Large-area nevus cell naevus (whole body segment covered similar to garment) --> in any case extended work-up
  • Melanosis neurocutanea
  • Naevus spilus

Acquired nevi

  • Lentigines
    • Lentigo simples
    • Lentigo senilis (solares), transition to seborrhoeic keratosis
    • Lentigo reticularis
    • Lentigo of the mucosa
  • Melanocytic nevi
    • Junctional type
    • Compound type
    • Dermal type
    • Halo nevus
    • Recurrent nevus
    • Pointed nevus
    • Deep infiltrating nevus
    • Spindle cell nevus
    • Meyerson--nevus

The aetiopathogenesis is not completely clear. It is assumed that it is a matter of cells migrating from the neural crest into the epidermis.

  • Sharply demarcated, facultative brownish/blackish papules and plaques
  • Multiple different types

Geographical position on the body:

  • Varies by type, certain types of melanocytosis for example have clear predilection sites associated with the diagnosis

Vertical position:

  • Epidermis: junctional melanocytic naevus
  • Epidermis & dermis: compound type of melanocytic naevus
  • Dermis: dermal melanocytic naevus

Degeneration to malignant melanoma.

  • Patients with >100 benign moles on the body have an 11x higher risk for malignant melanoma. This is a stronger risk factor than UV exposure in the history (this only increases the risk by 2.5x)
  • All individuals have these benign melanocyte tumours
  • There are new moles up to about 30 years of age, a spurt is seen between 20-30 years of age. After that, the moles decrease in number. 
  • If in doubt, biopsy a raised pigmented change, do not wait if melanoma is suspected.
  • 3 months interval may be too short to detect changes clinically. Therefore, better biopsy or wait 6 months, in case of doubt biopsy
  • In the acral area, a biopsy is often delayed because patients want to be protected from the pain of the biopsy. This leads to a delayed diagnosis of acral melanomas
  • Even by good dermatologists, about 10-20 moles are biopsied to detect a single melanoma. The aim is not to miss a melanoma - unfortunately they may not be clinically detectable

A dermatologist's check-up should be done regularly.

  1. Barnhill RL, Mihm MC, Magro CM. Plexiform spindle cell naevus: a distinctive variant of plexiform melanocytic naevus. Histopathology 1991;18:243-7.
  2. Mackie RM, Doherty VR. The desmoplastic melanocytic naevus: a distinct histological entity. Histopathology 1992;20:207-11.