Dark skin focalities: Difference between revisions
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[[File:Dark skin focalities.jpg|thumb|Dark skin focalities (in this case, from top left and clockwise: Spitz nevus, seborrheic keratosis, elevated melanocytic nevus and melanoma)]] | [[File:Dark skin focalities.jpg|thumb|Dark skin focalities (in this case, from top left and clockwise: Spitz nevus, seborrheic keratosis, elevated melanocytic nevus and melanoma)]] | ||
Skin with one or more areas that are darker than the surroundings. They are part of '''[[suspected malignant skin excisions]]'''. | |||
{{Fixation - standard}} | |||
{{Fixation - general notes}} | |||
{{Gross processing of skin excisions}} | |||
== | ==Microscopic evaluation== | ||
[[File:Pie chart of incidence and malignancy of pigmented skin lesions.png|thumb|370px|Various diagnoses of pigmented skin lesions, by relative incidence upon biopsy, and malignancy potential.]] | |||
===Melanocytic lesions=== | |||
Scrolling through the epidermis at intermediate magnification and then through the dermis at a lower magnification. | |||
=== | Melanocytic lesions (including nevus) are the most common, and can be classified as follows: | ||
[[File: | {|class="wikitable" | ||
! !!colspan=2| Atypia and/or dysplasia | |||
|- | |||
! !! Low !! High | |||
|- | |||
! Junction<br>between<br>epidermis<br>and dermis | |||
| [[File:Histopathology of melanocytic nevus.jpg|link=Junctional nevus|200px|center]] '''[[Junctional nevus]]''' || [[File:Histopathology of lentigo maligna.jpg|200px|center|link=Melanoma in situ]] '''[[Melanoma in situ]]''' | |||
|- | |||
! Dermis | |||
| [[File:Histopathology of dermal nevus, high magnification.jpg|160px|center|link=Dermal nevus]] '''[[Dermal nevus]]''' || [[File:Histopathology of nodular melanoma, high magnification.jpg|200px|center|link=Invasive melanoma of the skin]] '''[[Invasive melanoma of the skin|Invasive melanoma]]''' | |||
|} | |||
A '''compound nevus''' consists of both junctional and dermal melanocytic nevus nests. | |||
=== | ===Non-melanocytic=== | ||
<gallery> | <gallery mode=packed heights=180> | ||
File:Histopathology of | File:Histopathology of a pigmented basal-cell carcinoma.jpg|Pigmented '''[[basal-cell carcinoma]]''', with palisading cells around nests. | ||
File:Histopathology of seborrheic keratosis.jpg|link=Seborrheic keratosis|[[Seborrheic keratosis]] | |||
File:Histopathology of seborrheic keratosis.jpg|Seborrheic keratosis | |||
</gallery> | </gallery> | ||
{{Bottom}} | {{Bottom}} | ||
Latest revision as of 20:35, 8 June 2022
Author:
Mikael Häggström [note 1]
Skin with one or more areas that are darker than the surroundings. They are part of suspected malignant skin excisions.
Fixation
Generally 10% neutral buffered formalin.
See also: General notes on fixation
Gross processing of skin excisions
| Lesion size | |||
|---|---|---|---|
| <4 mm | 4 - 8 mm | 9 - 15 mm | |
| Benign appearance |
|
|
|
| Suspected malignancy | 
|
|
|
In table above, each top image shows recommended lines for cutting out slices to be submitted for further processing. Bottom image shows which side of the slice that should be put to microtomy. Dashed lines here mean that either side could be used. Further information: Gross processing of skin excisions
Microscopic evaluation
Melanocytic lesions
Scrolling through the epidermis at intermediate magnification and then through the dermis at a lower magnification.
Melanocytic lesions (including nevus) are the most common, and can be classified as follows:
| Atypia and/or dysplasia | ||
|---|---|---|
| Low | High | |
| Junction between epidermis and dermis |
 |
 |
| Dermis |  |
 |
A compound nevus consists of both junctional and dermal melanocytic nevus nests.
Non-melanocytic
-
Pigmented basal-cell carcinoma, with palisading cells around nests. -
Notes
- ↑ For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.
- ↑ The excision examples show a normal mole (upper row, benign appearance) and a superficial basal cell carcinoma (lower row, suspected malignancy).
Main page
References
- ↑ There are many variants for the processing of skin excisions. These examples use aspects from the following sources:
- . Handläggning av hudprover – provtagningsanvisningar, utskärningsprinciper och snittning (Handling of skin samples - sampling instructions, cutting principles and incision. Swedish Society of Pathology.
- For number of slices and coverage of lesions, depending on size. - Monica Dahlgren, Janne Malina, Anna Måsbäck, Otto Ljungberg. Stora utskärningen. KVAST (Swedish Society of Pathology). Retrieved on 2019-09-26.
- For slices towards the tips to determine radicality, which can be parallel to the slices through the lesions (shown), or as longitudinal slices that go through each tip. - . Dermatopathology Grossing Guidelines. University of California, Los Angeles. Retrieved on 2019-10-23.
- For microtomy of the most central side at the lesion - "The principles of mohs micrographic surgery for cutaneous neoplasia
- With a "standard histologic examination" that, in addition to the lesion, only includes one section from each side along the longest diameter of the specimen.
- It also shows an example of circular coverage, with equal coverage distance in all four directions.
- The entire specimen may be submitted if the risk of malignancy is high. - . Handläggning av hudprover – provtagningsanvisningar, utskärningsprinciper och snittning (Handling of skin samples - sampling instructions, cutting principles and incision. Swedish Society of Pathology.
Image sources