Melanocytic lesions: Difference between revisions

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[[Image:Blue nevus - intermed mag.jpg|thumb|right|A melanocytic lesion ([[blue nevus]]). [[H&E stain]]. (WC/Nephron)]]
'''Melanocytic lesions''' are commonly encountered in [[dermatopathology]] and an area which causes some difficulty, i.e. it is hard to decide in some cases whether a lesion is benign (e.g. [[Spitz nevus]]) or malignant ([[malignant melanoma]]).
'''Melanocytic lesions''' are commonly encountered in [[dermatopathology]] and an area which causes some difficulty, i.e. it is hard to decide in some cases whether a lesion is benign (e.g. [[Spitz nevus]]) or malignant ([[malignant melanoma]]).


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=Lentiginous melanocytic lesions=
=Lentiginous melanocytic lesions=
==Lentigo simplex==
==Lentigo simplex==
*[[AKA]] ''simple lentigo''.<ref>URL: [http://www.dermnetnz.org/lesions/lentigo-simplex.html http://www.dermnetnz.org/lesions/lentigo-simplex.html]. Accessed on: 27 March 2013.</ref>
{{Main|Lentigo simplex}}
===General===
*Benign.
*Usually <40 years old.
 
Fits into the larger category of ''lentiginous melanocytic proliferations'' - these include:<ref name=Ref_Derm438>{{Ref Derm|438}}</ref>
*[[Solar lentigo]].
*Lentigo simplex.
*[[Lentiginous nevus]].
*Lentiginous [[melanoma in situ]].
 
Associated syndromes:<ref name=dermamin_ls>URL: [http://dermaamin.com/site/histopathology-of-the-skin/64-l/1852-lentigo-simplex-.html http://dermaamin.com/site/histopathology-of-the-skin/64-l/1852-lentigo-simplex-.html]. Accessed on: 17 December 2012.</ref>
*[[Peutz-Jeghers syndrome]].
*[[LEOPARD syndrome]].
*[[LAMB syndrome]].
 
===Gross===
*Small flat pigmented lesion.<ref name=Ref_WMSP498>{{Ref WMSP|498}}</ref>
 
DDx - clinical:
*[[Melanocytic nevus]].<ref name=pmid19536147>{{Cite journal  | last1 = Hafner | first1 = C. | last2 = Stoehr | first2 = R. | last3 = van Oers | first3 = JM. | last4 = Zwarthoff | first4 = EC. | last5 = Hofstaedter | first5 = F. | last6 = Klein | first6 = C. | last7 = Landthaler | first7 = M. | last8 = Hartmann | first8 = A. | last9 = Vogt | first9 = T. | title = The absence of BRAF, FGFR3, and PIK3CA mutations differentiates lentigo simplex from melanocytic nevus and solar lentigo. | journal = J Invest Dermatol | volume = 129 | issue = 11 | pages = 2730-5 | month = Nov | year = 2009 | doi = 10.1038/jid.2009.146 | PMID = 19536147 }}</ref>
 
===Microscopic===
Features:<ref name=Ref_WMSP498>{{Ref WMSP|498}}</ref>
*Melanocytes in epidermis only.
**Melanocytes basally located (normal location) with hyperpigmentation.
*No melanocytic nests.
*+/-Mild/moderate elongation of the rete ridges.<ref name=pmid19536147/>
 
DDx:<ref name=humpath_ls/>
*[[Solar lentigo]] - solar elastosis, usu. in sun exposed areas.
*[[Ephelis]] (freckle) - change with UV light exposure.
*Melanotic macule.
*[[Lentiginous nevus]] - has melanocytic nests.
 
====Images====
*[http://dermaamin.com/site/histopathology-of-the-skin/64-l/1852-lentigo-simplex-.html Lentigo simplex - several images (dermamin.com)].<ref name=dermamin_ls/>
*[http://www.humpath.com/IMG/jpg/lentigo_simplex_20x.jpg Lentigo simplex (humpath.com)].<ref name=humpath_ls>URL: [http://www.humpath.com/?lentigo-simplex http://www.humpath.com/?lentigo-simplex]. Accessed on: 17 December 2012.</ref>
<gallery>
Image:Skin_Tumors-171.jpg | Simple lentigo. (WC)
</gallery>
 
===Sign out===
<pre>
SKIN LESION, LEFT ABDOMEN, BIOPSY:
- SIMPLE LENTIGO, COMPLETELY EXCISED IN THE PLANE OF SECTION.
</pre>
 
<pre>
SKIN LESION, LEFT ABDOMEN, BIOPSY:
- BENIGN SIMPLE LENTIGO.
</pre>
 
====Micro====
The sections show skin with increased numbers of small pigmented melanocytes at the dermal-epidermal junction. The rete ridges are mildly elongated. No solar damage is apparent. No dermal melanocytes are identified. No melanocytic nests are identified. No nuclear atypia is apparent.


==Solar lentigo==
==Solar lentigo==
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**Classically at the tips of the rete ridges.
**Classically at the tips of the rete ridges.
*No (melanocyte) nuclear atypia.
*No (melanocyte) nuclear atypia.
*Solar damage ([[solar elastosis]]).<ref name=pmid19536147/>
*Solar damage ([[solar elastosis]]).<ref name=pmid19536147>{{Cite journal  | last1 = Hafner | first1 = C. | last2 = Stoehr | first2 = R. | last3 = van Oers | first3 = JM. | last4 = Zwarthoff | first4 = EC. | last5 = Hofstaedter | first5 = F. | last6 = Klein | first6 = C. | last7 = Landthaler | first7 = M. | last8 = Hartmann | first8 = A. | last9 = Vogt | first9 = T. | title = The absence of BRAF, FGFR3, and PIK3CA mutations differentiates lentigo simplex from melanocytic nevus and solar lentigo. | journal = J Invest Dermatol | volume = 129 | issue = 11 | pages = 2730-5 | month = Nov | year = 2009 | doi = 10.1038/jid.2009.146 | PMID = 19536147 }}</ref>


Notes:
Notes:
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==Acral nevus==
==Acral nevus==
*[[AKA]] ''melanocytic nevus with intraepidermal ascent of cells'' (MANIAC).
*[[AKA]] ''melanocytic nevus with intraepidermal ascent of cells'' ([[MANIAC]]).
*[[AKA]] ''volar nevus''.
*[[AKA]] ''volar nevus''.
{{Main|Acral nevus}}
{{Main|Acral nevus}}
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**Should stain approximally the same number of cells as Melan A.
**Should stain approximally the same number of cells as Melan A.
*Ki-67 -- only rare cells.
*Ki-67 -- only rare cells.
==Nodal nevus==
*AKA ''nevus in lymph node'' and ''benign nevus cells in lymph node''.
{{Main|Nodal nevus}}


=Miscellaneous=
=Miscellaneous=
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*[[Non-malignant skin disease]].
*[[Non-malignant skin disease]].
*[[Pigmented lesions of the oral cavity]].
*[[Pigmented lesions of the oral cavity]].
*[[Melanosis coli]].
*[[Small bowel pseudomelanosis]].


=References=
=References=
Retrieved from "https://librepathology.org/wiki/Melanocytic_lesions"