Last Updated: 2022-03-25
Author(s): Anzengruber F., Navarini A.
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
- Naevus bleu
- Mongolian spot
- Naevus Ota (head, also called nevus fuscocoeruleus ophtalmomaxillaris)
- Naevus Ito (shoulders, "inferior", also called nevus fuscocoeruleus deltoideoacromialis
- 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
- 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
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
- 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
- Barnhill RL, Mihm MC, Magro CM. Plexiform spindle cell naevus: a distinctive variant of plexiform melanocytic naevus. Histopathology 1991;18:243-7.
- Mackie RM, Doherty VR. The desmoplastic melanocytic naevus: a distinct histological entity. Histopathology 1992;20:207-11.