Skin and subcutaneous (L00-L99).
Dermal melanocytic nevi (pigmented nevi).
- Mongolian spot – indistinct gray-blue discoloration of the skin in the buttock/back area; regresses by puberty; usually seen in mongolians
- Nevus coeruleus (blue nevus) – coarse blue-black nodules that appear mainly on the back of the hand or arm.
- Naevus fusco-coeruleus – blurred flat blue-black pigmentation in the area of the face (naevus Ota; synonym: oculodermal melanocytosis)/shoulder (naevus Ito); possibly with hypertrichosis (increased body and facial hair; without a male distribution pattern); occurs in Mongolians and Japanese.
Epidermal melanocytic nevi – refers to marks characterized by a sharply demarcated brown patch.
- Café-au-lait spot (nevus pigmentosus).
- Ephelides (freckles)
- Lentigines (lentigo simplex)
- Melanosis naeviformis (Becker’s nevus) – extensive brown colored skin area, which occurs in combination with hypertrichosis (increased body and facial hair; without a male distribution pattern).
- Nevus spilus – combination of café-au-lait spots (CALF) and small-spotted pigment cell nests.
Nevus cell nevus (NZN) – marks that pass through the following stages.
- Junctional nevus – sharply demarcated spot/dot-shaped marks that are homogeneously brown(-black) in color.
- Compound nevus – sharply demarcated, usually nodular brown(-black) marks, often with a fissured surface; hypertrichosis may be concomitant; usually form from junctional nevi
- Dermal nevi – papular brown marks with hair trimming.
Special forms of nevus cell nevi
- Benign juvenile melanoma (spindle cell nevus; Spitz tumor) – circumscribed benign nodular marks occurring in children/adolescents.
- Dysplastic nevus (atypical nevus, active nevus) – acquired nevus cell nevus with outgrowths, irregular pigmentation/color changes, increase in size, signs of inflammation.
- Halo nevus (Sutton nevus) – harmless marks characterized by a white halo.
- Nevus pigmentosus et pilosus (giant pigmented nevus) – often appearing as bathing trunks nevus in the context of neurocutaneous melanosis.
Vascular nevi, hemangiomas.
- Nevus flammeus (port-wine stain; nevus teleangiectaticus; planar hemangioma) – sharply demarcated light to blue-red spots.
- Medial nevus flammeus – common on neck, forehead; often regress; newborns sometimes have a pale port-wine stain on neck, popularly known as “stork bite.”
- Lateral nevus flammeus – often localized on the face; rarely regress; may occur as part of complex malformations
- Nevus araneus (synonyms: Nevus stellatus; spider nevus, star nevus, or vascular spider or Eppinger’s star, spider nevus, spider nevi) – change occurring in children or in advanced liver disease, in which a central papule is surrounded by star-shaped venules.
- Teleangictasia hereditaria haemorrhagica (Osler-Rendu disease) – dilatation of the end-stromal vessels caused by an autosomal dominant hereditary disorder
- Hemangioma – pale to blackish-blue vascular growths that occur in early childhood or are congenital.
- Granuloma pyogenicum (granuloma teleangiectaticum, botryomycoma) – benign spherical soft neoplasms that occur after an infected injury; differential diagnoses:
- Angioma – benign vascular neoplasm.
- Fibroma – benign growth of connective tissue.
- Melanoma – neoplasm originating from pigment-producing tissue.
Epidermal nevi
- Congenital, usually striated thickening of the epidermis.
- Differential diagnoses: lichen ruber (nodular lichen); psoriasis (psoriasis).
Sebaceous nevi (nevus sebaceus).
- Sharply circumscribed often spherical marks arranged in a cobblestone to papillomatous pattern; occurs more frequently in childhood/adolescence
- Differential diagnoses: senile sebaceous gland hyperplasia, adenoma sebaceum (synonyms: nevus Pringle, adenoma sebaceum senile, sebaceous gland adenoma).
Other nevi
- Apocrine/ecrine sweat gland nevi
- Connective tissue nevi
- Elastica nevi
- Hair nevi
- Comedone nevi
- Nevus lipomatosus superficialis – it is a circumscribed fatty tissue nevus with development of fatty tissue lobules throughout the dermis (skin).
