Nevus: Difference between revisions

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List of terms related to Nevus

	Nevus
	Classification and external resources
File:1D-I-k ouC8.jpg
	A nevus on a leg
ICD-10	I78.1
ICD-9	448.1, 216.0-216.9
MeSH	D009506

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Revision as of 13:47, 25 August 2014

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]

Overview

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 or mucosa. These lesions are commonly named birthmarks or beauty marks. Nevi are benign by definition. However, 25% 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 distinguished 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

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

Hemangioma (strawberry mark or nevus).

Diagnosis of nevi

File:Dermatoscope1.JPG

A dermatoscope

File:Dermatoscope.jpg

A modern polarized dermatoscope

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]

References

↑ Template:DorlandsDict
↑ Sam, Amir H.; James T.H. Teo (2010). Rapid Medicine. Wiley-Blackwell. ISBN 1405183233.
↑ [1]^{[dead link]}

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

[1] Template:DorlandsDict

[2] Sam, Amir H.; James T.H. Teo (2010). Rapid Medicine. Wiley-Blackwell. ISBN 1405183233.

[3] [1]^{[dead link]}

[1]

[2]

[3]

@@ Line 1: / Line 1: @@
+{{Infobox disease
+|  Name           = Nevus
+|  Image          = 1D-I-k ouC8.jpg
+|  Caption        = A nevus on a leg
+|  DiseasesDB     =
+|  ICD10          = {{ICD10|I|78|1|i|70}}
+|  ICD9           = {{ICD9|448.1}}, {{ICD9|216.0}}-{{ICD9|216.9}}
+|  ICDO           =
+|  OMIM           =
+|  MedlinePlus    =
+|  eMedicineSubj  =
+|  eMedicineTopic =
+|  MeshID         = D009506
+}}
 __NOTOC__
-{{Infobox_Disease |
-  Name           = {{PAGENAME}} |
-  Image          = Nevus.jpg |
-  Caption        = Photograph of a nevus on an arm |
-}}
 {{SI}}
 {{CMG}}
-{{SK}}  Naevus
+==Overview==
-==Overview==
+'''Nevus''' (or '''naevus''', plural '''nevi''' or '''naevi''', from ''nævus'', [[Latin language|Latin]] for "[[birthmark]]") is the medical term for sharply circumscribed<ref>{{DorlandsDict|six/000072214|nevus}}</ref> and [[chronic (medicine)|chronic]] [[lesion]]s of the [[skin]] or [[mucosa]]. These lesions are commonly named '''birthmarks''' or '''beauty marks'''. Nevi are [[benign tumor|benign]] by definition. However, 25% of malignant melanomas (a skin cancer) arise from pre-existing nevi.<ref>{{cite book |last= Sam |first= Amir H. |author2=James T.H. Teo  |title= [[Rapid Medicine]] |publisher= [[Wiley-Blackwell]] |year= 2010 |isbn= 1405183233}}</ref> 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 [[melanocyte]]s. Histologically, melanocytic nevi are distinguished from [[lentigo|lentigines]] (also a type of benign pigmented [[macule]]) by the presence of nests of melanocytes, which lentigines (plural form of lentigo) lack.
-'''Nevus''' is a general term that refers to a number of different (usually benign) pigmented lesions of the skin. Most [[birthmark]]s and [[Mole (skin marking)|moles]] are placed into the category of nevi.
 ==Classification==
-* [[mole (skin marking)|Melanocytic nevus]]: Nevus cells are normally localized in the basal layer of the [[Epidermis (skin)|epidermis]]. Their proliferation may appear in the form of a:
+[[epidermis (skin)|Epidermal]] nevi are derived from [[keratinocyte]]s or derivatives of keratinocytes. [[Connective tissue]] nevi are derived from connective tissue cells like [[adipocyte]]s and [[fibroblasts]]. [[vascular tissue|Vascular]] nevi are derived from structures of the blood vessels. ''See [[birthmark]] for a more complete discussion''
-** Junctional nevus: Located just superficial to the junction of the [[epithelium]] and the underlying [[connective tissue]]. A junctional nevus is flat and is not detected by palpation.
-** Compound nevus: Located within the interface of the epithelium and the underlying connective tissue. A compound nevus is raised and solid.
+===Melanocytic nevus===
-** Intradermal nevus: The most common lesion of the skin, these lie exclusively within the dermis.  They are regular and round, their cells having a central [[Cell nucleus|nucleus]] and single [[nucleolus]]. Some melanocytes may present [[melanin]] pigment in the cytoplasm (dark-brown, granular).
+{{main|Melanocytic nevus}}
-** Intramucosal nevus: Although all oral nevi are rare, intramucosal nevi are the most commonly seen there, as they are found most frequently on the hard palate.
+*[[Congenital nevus]]: a melanocytic nevus present at birth or near birth.
-** [[Spider angioma]], also known as nevus araneus
+*Acquired melanocytic nevus: a melanocytic nevus acquired later in life, and not at or near birth.  Most melanocytic nevi are of the acquired variety.
-* [[Dysplastic nevus]]
+*Melanocytic nevus (nevomelanocytic nevus, nevocellular nevus): benign proliferation of [[melanocyte]]s, 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).
-* [[Blue nevus]]
+*[[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.
-* [[Blue rubber bleb nevus syndrome]]
-* Nevus flammeus ([[port-wine stain]])
+===Epidermal nevus===
-* Giant hairy nevus: These large pigmented (often hairy) congenital nevi are important because of their increased risk (10 to 15%) of conversion into malignant melanoma.
+* 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===
+* [[Hemangioma]] (strawberry mark or nevus).
+== Diagnosis of nevi ==
+[[Image:Dermatoscope1.JPG|thumb|A [[dermatoscope]]]]
+[[Image:Dermatoscope.jpg|thumb|A modern polarized dermatoscope]]
+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.<ref>[http://www.pathologyresources.com/AFIP/melanocytic/chap02.htm ]{{dead link|date=August 2012}}</ref>
+==See also==
+* [[Becker's nevus]]
 ==References==
 {{Reflist|2}}
-{{Epithelial neoplasms}}
+==External links==
+{{Wiktionary}}
-[[Category:Dermatology]]
+{{commons category}}
-[[Category:Oral pathology]]
+* [http://www.pathologyatlas.ro/intradermal-melanocytic-nevus.php Atlas of Pathology] Section of a melanocytic nevus
-[[Category:Oncology]]
+* [http://www.medscape.com/features/slideshow/mole-melanoma eMedicine: Mole or Melanoma? Tell-Tale Signs in Benign Nevi and Malignant Melanoma: Slideshow]
-[[category:primary care]]
+* [http://www.nevus.org/ Nevus Outreach, Inc.]
+* [http://www.nbclosangeles.com/video/#!/on-air/as-seen-on/Local-Surgeon-Helping-Little-Girl-From-Philippines-with-Life-Changing-Surgery/134481563/ Pediatric plastic surgeon helps little girl with nevus NBC LA]
-[[de:Nävus]]
-[[es:Nevus]]
-[[fr:Nævus]]
-[[it:Nevo]]
-[[la:Naevus]]
-[[ja:母斑]]
-[[pl:Znamię]]
-[[pt:Nevo]]
-{{WikiDoc Help Menu}}
+{{Diseases of the skin and appendages by morphology}}
-{{WikiDoc Sources}}

File:1D-I-k ouC8.jpg
Nevus
Classification and external resources
A nevus on a leg
ICD-10	I78.1
ICD-9	448.1, 216.0-216.9
MeSH	D009506