Nevus melanocytic (overview) D22.-

Benign, congenital or acquired melanocytic, brown to brown-black, more rarely reddish or skin-coloured, spotty, nodular, plaque or nodular melanocytic tumours, which mostly occur in plural, but also solitary form. Melanocytic nevi may be restricted to the epidermis (lentigo simplex, junctional melanocytic nevus), located in the epidermis and dermis (compound type of melanocytic nevus) or exclusively in the dermis (dermal melanocytic nevus). This clinical/histological typing describes a sequential developmental process that all melanocytic nevi go through in stages.

Classification of congenital and acquired melanocytic nevi according to histological and clinical criteria:

• Acquired melanocytic nevus:
  • lentigo simplex
  • Lentigo solaris (senilis)
  • Lentigo, reticular
  • Lentigo of the mucosa (melanosis of the mucosa)
  • Nevus melanocytic acral
  • Nevus melanocytic dysplastic (atypical)
  • Ordinary melanocytic nevus
    • Usual melanocytic nevus junctional type
    • Common melanocytic nevus compound type
    • Common melanocytic nevus dermal type
  • Nevus melanocytic halo-nevus
  • recurrent melanocytic nevus
  • Nevus Spitz
  • Naevus melanocytic deep infiltrating
  • Nevus melanocytic spindle cell nevus pigmented
  • Bladder cell nevus (balloon cell nevus)
  • Meyerson's melanocytic nevus.
• congenital melanocytic nevus:
  • Small congenital melanocytic nevus (< 4 cm)
  • Large congenital melanocytic nevus (> 4 cm)
  • Giant congenital melanocytic nevus (e.g. swimming trunks type)
  • melanosis neurocutanea
  • nevus spilus
• Dermal melanocytosis:
  • Mongolian spot
  • Nevus fuscocoeruleus ophthalmomaxillaris (Naevus Ota)
  • Naevus fuscocoeruleus deltoideoacromialis (Naevus Ito)
• Blue Nevus

It has been postulated that melanocytic nevi originate from cells migrating from the neural crest into the epidermis. It is likely that melanocytes and "nevus cells" represent identical cell populations, so that the term "nevus cell" can be dispensed with in connection with melanocytic nevi (aka nevus cell nevus).

On the whole integument, also on superficial mucous membranes possible.

• Junction type (initial epidermal stage)
• Compound type (epidermo-dermal)
• Dermal type: Dermal melanocytic nevus.

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3. Maitra A et al (2002) Loss of heterozygosity analysis of cutaneous melanoma and benign melanocytic nevi: laser capture microdissection demonstrates clonal genetic changes in acquired nevocellular nevi. Hum Pathol 33: 191-197
4. Ruiter DJ et al (2003) Current diagnostic problems in melanoma pathology. Seminar Cutan Med Surg 22: 33-41
5. Schulz H (1992) Reflected light microscopic score for the differential diagnosis of dysplastic nevi. dermatologist 43: 487-490
6. Schulz H (1994) Reflected light microscopic criteria of benign melanocytic pigment moles of the skin. Nude Dermatol 20: 2-6
7. Synnerstad I et al (2004) Fewer melanozcytic nevi found in children with active atopic dermatitis than in children without dermatitis. Arch Dermatol 140:1471-1475
8. Tomita K et al (1998) A nevocellular nevus consisting mostly of nevic corpuscles. J Dermatol 25: 134-135