NaevusD22.L
Synonym(s)
DefinitionThis section has been translated automatically.
The term "nevus" has 2 meanings:
- As a pathogenetic term equivalent to " hamartoma of the skin". A nevus is a visible, sharply defined, often congenital, but also postnatally manifesting, long-term malformation of the skin or mucosa, which is characterized by excess, rarely also by underdevelopment or malformation, of one or more components of skin or mucosa, and which aetiopathogenetically represents a cutaneous mosaic (see also under malformation).
- Furthermore, the term "nevus" also finds a general use for a true, benign, melanocytic tumor(melanocytic nevus - formerly also called nevus cell nevus).
EtiopathogenesisThis section has been translated automatically.
Hamartomas of the skin are caused by abnormal development of the epidermis with increased or decreased pigmentation and/or of the skin appendages, vessels (vascular hamartomas), nerves or connective tissue(connective tissue nevus). Various combinations of malformations are possible (organoid nevi). They are named after the predominant tissue type (e.g. sweat gland nevus).
Systematized hamartomas of the skin are those that are distributed over a body region. Systematized hamartomas of the skin usually follow the Blaschko lines in their arrangement (classification see Tab. 1).
Differential diagnosisThis section has been translated automatically.
The term nevus is to be distinguished from the term malformation as a defective development from an embryonic anlage (e.g. branchial remnants in lateral neck cysts).
In clinical terminology, the term "nevus" is used synonymously with an acquired pigmentary tumor ( melanocytic nevus). However, most melanocytic nevi are not nevi in the sense of a "hamartoma of the skin" but are true acquired pigment cell tumors. For differential diagnosis see below. Melanocytic nevus.
TablesThis section has been translated automatically.
Classification of the nevi (n. Altmeyer 2015)
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Melanocytic hamartomas
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Melanocytic hamartomas |
Epidermal |
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Dermal |
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Melanocytic hamartoma |
Epidermal/Dermal |
Congenital melanocytic nevi |
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Non-melanocytic hamartomas |
Epithelial hamartomas (are called "epidermal nevi") |
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Nevus, sweat gland nevus | |||
Connective tissue hamartomas |
Lumbosacral connective tissue nevus |
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coarse nodular disseminated connective tissue nevus | |||
Vascular malformations |
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Teleangiectasia hereditaria haemorrhagica | |||
Hamartomas of the adipose tissue |
Familial lipomas |
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LiteratureThis section has been translated automatically.
- Blum A et al (2003) The dermoscopic classification of atypical melanocytic naevi (Clark naevi) is useful to discriminate benign from malignant melanocytic lesions. Br J Dermatol 149: 1159-1164
- Dawson HA et al (1996) A prospective study of congenital melanocytic nevi: progress report and evaluation after 6 years. Br J Dermatol 134: 617-623
- Happle R (2004) Cutaneous mosaics: patterns and molecular mechanisms. Dt Medical Journal 101: 1575-1580