World Library  
Flag as Inappropriate
Email this Article

Nevi

Article Id: WHEBN0002167247
Reproduction Date:

Title: Nevi  
Author: World Heritage Encyclopedia
Language: English
Subject: International Classification of Diseases for Oncology, Stanisław Brzozowski (writer)
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Nevi

Not to be confused with Naevius, Nevis, or Nevius.
"Naevus" and "Nevi" redirect here. For the British experimental rock group, see Naevus (band). For the Eritrean footballer, see Nevi Ghebremeskez. For the Norwegian bank, see Nevi (company).
Nevus
Classification and external resources
Error creating thumbnail: File seems to be missing:
A nevus on a leg
ICD-10 9 MeSH D009506

Nevus (or naevus, plural nevi or naevi, from nævus, Latin for "birthmark") is the medical term for sharply circumscribed[1] and chronic lesions of the skin. These lesions are commonly named birthmarks or beauty marks. Nevi are benign by definition. However, 50% of malignant melanomas (a skin cancer) arise from pre-existing nevi.[2] Using the term nevus and nevi loosely, most physicians and dermatologists are actually referring to a variant of nevus called the "melanocytic nevus", which are composed of melanocytes. Histologically, melanocytic nevi are differentiated from lentigines (also a type of benign pigmented macule) by the presence of nests of melanocytes, which lentigines (plural form of lentigo) lack.

Classification

Epidermal nevi are derived from keratinocytes or derivatives of keratinocytes. Connective tissue nevi are derived from connective tissue cells like adipocytes and fibroblasts. Vascular nevi are derived from structures of the blood vessels. See birthmark for a more complete discussion

Melanocytic nevus

Main article: Melanocytic nevus
  • Congenital nevus: a melanocytic nevus present at birth or near birth.
  • Acquired melanocytic nevus: a melanocytic nevus acquired later in life, and not at or near birth. Most melanocytic nevi are of the acquired variety.
  • Melanocytic nevus (nevomelanocytic nevus, nevocellular nevus): benign proliferation of melanocytes, the skin cells that make the brown pigment melanin. Hence, most nevi are brown to black. They are very common; almost all adults have at least one, usually more. They may be congenital or acquired (usually at puberty).
  • Dysplastic nevus: usually an acquired melanocytic nevus with abnormal features making it difficult to distinguish from a melanoma. It can be a marker for an individual at risk for developing melanomas.

Epidermal nevus

  • Epidermal nevus: congenital, flesh-colored, raised or warty, often linear lesion, usually on the upper half of the body.
  • Nevus sebaceus: variant of epidermal nevus on the scalp presenting as a hairless, fleshy or yellowish area.

Connective tissue nevus

  • Connective tissue nevus: fleshy, deep nodules. Rare.

Vascular nevus

Diagnosis of nevi


Clinical diagnosis of a melanocytic nevus from other nevi can be made with the naked eye using the ABCD guideline, or using dermatoscopy. The main concern is distinguishing between a benign nevus, a dysplastic nevus, and a melanoma. Other skin tumors can resemble a melanocytic nevus clinically, such as a seborrheic keratosis, pigmented basal cell cancer, hemangiomas, and sebaceous hyperplasia. A skin biopsy is required when clinical diagnosis is inadequate or when malignancy is suspected.

Normal evolution or maturation of melanocytic nevi

All melanocytic nevi will change with time - both congenital and acquired nevi. The "normal" maturation is evident as elevation of the lesion from a flat macule to a raised papule. The color change occurs as the melanocytes clump and migrate from the surface of the skin (epidermis) down deep into the dermis. The color will change from even brown, to speckled brown, and then losing the color and becomes flesh colored or pink. During the evolution, uneven migration can make the nevi look like melanomas, and dermatoscopy can help in differentiation between the benign and malignant lesions.[3]

See also

References

External links

  • Atlas of Pathology Section of a melanocytic nevus
  • eMedicine: Mole or Melanoma? Tell-Tale Signs in Benign Nevi and Malignant Melanoma: Slideshow
  • Nevus Outreach, Inc.
  • Pediatric plastic surgeon helps little girl with nevus NBC LA
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.