Editing Melanocytic nevus (section)

===Classification===
Melanocytic nevi can mainly be classified by depth, being congenital versus acquired, and/or specific dermatoscopy or [[histopathology]] patterns:
;Depth:
{|class="wikitable"
! Depth class !! Location of nevus cells !! Other characteristics !! Image !! [[International classification of diseases|ICD]]
|-
! Junctional nevus
| Along the junction of the [[epidermis]] and the underlying [[dermis]].<ref>[http://www.cancer.gov/dictionary?CdrID=44285 Junctional nevus] entry in the public domain NCI Dictionary of Cancer Terms </ref>
| May be colored and slightly raised.<ref>{{cite web |title=NCI Definition of Cancer Terms |url=https://www.cancer.gov/publications/dictionaries/cancer-terms/def/junctional-nevus |website=www.cancer.gov |publisher=National Cancer Institute |access-date=5 December 2018}}</ref> 
| [[File:Skin Tumors-200.jpg|190px]]
| [[ICD10]]: D22<br>[[International Classification of Diseases for Oncology|ICDO]]: M8740/0 
|-
! Compound nevus
|Both the epidermis and dermis.<ref>{{cite web |title=NCI Definition of Cancer Terms |url=https://www.cancer.gov/publications/dictionaries/cancer-terms/def/compound-nevus |website=www.cancer.gov |publisher=National Cancer Institute |access-date=5 December 2018}}</ref>
| 
| [[File:Skin tumors-201.jpg|190px]]
| ICD10: D22 ([[ILDS]] D22.L14)<br>ICDO: 8760/0 
|-
! Intradermal nevus
| Within the [[dermis]].
| A classic mole or [[birthmark]]. It typically appears as an elevated, dome-shaped bump on the surface of the skin.<ref name=mayo/><ref name=aad.org/>
| [[File:Micrograph of an intradermal melanocytic nevus.jpg|190px]]
|}
<gallery>
File:Histopathology of a dermal nevus.jpg|Small dermal nevus, with nests of nevus cells (arrows)
</gallery>

;Congenital versus acquired
*[[Congenital nevus]]: Small to large nevus present at or near time of birth.  Small ones have low potential for forming [[melanomas]], however the risk increases with size, as in the giant pigmented nevus.<ref>{{Cite web|last=Reference|first=Genetics Home|title=Giant congenital melanocytic nevus|url=https://ghr.nlm.nih.gov/condition/giant-congenital-melanocytic-nevus|access-date=2020-09-18|website=Genetics Home Reference|language=en}}</ref>
*'''Acquired nevus''':  Any melanocytic nevus that is not a congenital nevus or not present at birth or near birth.

;
'''Specific [[dermatoscopy]] or [[histopathology]] patterns''' 
{|class="wikitable"
! Type !! Characteristics !! Photo-<br>graphy || [[Histopathology|Histo-<br>pathology]]
|-
| '''[[Dysplastic nevus]]''' || Usually a compound nevus with cellular and architectural [[dysplasia]]. Like typical moles, dysplastic nevi can be flat or raised. While they vary in size, dysplastic nevi are typically larger than normal moles and tend to have irregular borders and irregular coloration. Hence, they resemble [[melanoma]], appear worrisome, and are often removed to clarify the diagnosis. Dysplastic nevi are markers of risk when they are numerous, such as in people with [[dysplastic nevus syndrome]]. According to the National Institute of Health (NIH), doctors believe that, when part of a series or syndrome of multiple moles, dysplastic nevi are more likely than ordinary moles to develop into the most virulent type of skin cancer called melanoma.<ref>{{cite web|title=Familial atypical multiple mole melanoma syndrome|url=https://rarediseases.info.nih.gov/diseases/9281/familial-atypical-multiple-mole-melanoma-syndrome|website=Genetic and Rare Diseases Information Center (GARD)|publisher=NIH|access-date=23 January 2018}}</ref>
| [[File:Dysplastic nevi (2) - crop.jpg|100px|left]]
In this case, the central portion is a complex papule, and the periphery is macular, irregular, indistinct and slightly pink. 
| [[File:Dysplastic_nevus_-_add_-_high_mag.jpg|180px]] Characteristic [[rete ridge]] bridging, shouldering, and lamellar fibrosis. [[H&E stain]].
|-
| '''[[Blue nevus]]''' || It is blue in color as its [[melanocytes]] are very deep in the skin.
| [[File:Blue Nevus (crop).jpg|140px]]
| [[File:blue nevus - intermed mag.jpg|85px|left]] Characteristic pigmented [[melanocyte]]s between bundles of [[collagen]]. [[H&E stain]].
|-
| '''[[Spitz nevus]]''' || A distinct variant of intradermal nevus, usually in a child.  
| [[File:Spitz nevus.jpg|180px]] They are raised and reddish (non-pigmented).
| [[Image:Spitz nevus - intermed mag.jpg|160px|left]] Characteristic vertically arranged nests of cells ("hanging bananas"). [[H&E stain]].
|-
| '''[[Giant pigmented nevus]]''' || Large, pigmented, often hairy congenital nevi. They are important because [[melanoma]] may occasionally (10 to 15%) appear in them.{{Citation needed|date=June 2016}}
| [[File:Giant melanocytic nevus - photography.jpg|180px]]
| [[File:Giant melanocytic nevus - histopathology.jpg|180px]]
|-
| '''[[Nevus of Ito]]''' and '''[[nevus of Ota]]''' || Congenital, flat brownish lesions on the face or shoulder.<ref>{{cite web|title=Nevus of Ito|url=https://rarediseases.info.nih.gov/diseases/10830/nevus-of-ito|website=Genetic and Rare Disease Information Center (GARD)|publisher=NIH|access-date=23 January 2018}}</ref>
| [[File:Nevus of Ito.jpg|150px|left]] Nevus of Ito.
|
|-
| '''[[Mongolian spot]]''' || Congenital large, deep, bluish discoloration which generally disappears by puberty. It is named for its association with East Asian ethnic groups but is not limited to them.<ref>{{cite web|title=Mongolian Spot|url=http://www.aocd.org/?page=MongolianSpot|website=AOCD Dermatologic Disease Database|publisher=American Osteopathic College of Dermatology|access-date=23 January 2018|archive-url=https://web.archive.org/web/20180124070605/http://www.aocd.org/?page=MongolianSpot|archive-date=24 January 2018|url-status=dead}}</ref>
| [[File:Mongolianspotphoto.jpg|150px]]
|
|}

;Recurrence
[[Recurrent nevus]]:  Any incompletely removed nevus with residual melanocytes left in the surgical wound. It creates a dilemma for the patient and physician, as these scars cannot be distinguished from a melanoma.<ref name="abd">{{cite journal|title=The recurrent nevus phenomenon|journal=Anais Brasileiros de Dermatologia|date=July–August 2017|volume=92|issue=4|pages=531–533|doi=10.1590/abd1806-4841.20176190|pmid=28954104|pmc=5595602|last1=Castagna|first1=Rafaella Daboit|last2=Stramari|first2=Juliana Mazzoleni|last3=Chemello|first3=Raíssa Massaia Londero}}</ref>