Epidermoid cyst: Difference between revisions
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*Abundant keratin flakes in cyst lumen | *Abundant keratin flakes in cyst lumen | ||
*Often giant cell granuloma in ruptured cysts, similar to foreign body granuloma | *Often giant cell granuloma in ruptured cysts, similar to foreign body granuloma | ||
===Differential diagnosis=== | |||
====Pilomatricoma==== | |||
[[File:Histopathology of pilomatricoma, high magnification, annotated.jpg|thumb|240px|Histopathology of pilomatricoma, high magnification, H&E stain, showing the characteristic components.]] | |||
The characteristic components of a pilomatricoma include a ''stroma'' of fibrovascular connective tissue | |||
surrounding irregularly shaped, lobulated islands containing ''basaloid cells'' (being darkly stained, round or elongated, with indistinct cell borders and minimal cytoplasm, with nuclei being round to ovoid, deeply basophilic and generally prominent nucleoli), which abruptly or gradually transitions into ''ghost cells'' (having abundant, pale, eosinophilic cytoplasm, well defined cell borders and a central clear area, but only only faint traces of nuclear material), which in turn may transition into keratinaceous to amorphous ''necrosis''.<ref name=atlas>{{cite web|url=http://atlasgeneticsoncology.org/Tumors/PilomatricomaID5153.html|title=Skin: Pilomatricoma|website=Atlas of Genetics and Cytogenetics in Oncology and Haematology|date=2009-06-01|author=Punnya V Angadi}}</ref> | |||
The presence of calcifications with foreign body giant cells is common within pilomatricomas.<ref>{{cite book |editor1-first=David E. |editor1-last=Elder |editor2-first=Bernett L. |editor2-last=Johnson |editor3-first=Rosalie |editor3-last=Elenitsas |year=2005 |title=Lever's Histopathology of the Skin |publisher=Lippincott Williams & Wilkins |isbn=978-0-7817-3742-5 }}{{page needed|date=July 2016}}</ref> | |||
====Trichilemmal cyst==== | |||
[[File:Histopathology of trichilemmal cyst - annotated.jpg|thumb|Trichilemmal cyst.]] | |||
The constitution of a trichilemmal cyst (also called pilar cyst), from external (top) to internal (bottom):<ref>{{cite web|url=https://www.medscape.com/answers/1058907-121502/which-histologic-findings-are-characteristic-of-trichilemmal-cyst-pilar-cyst|title=Which histologic findings are characteristic of trichilemmal cyst (pilar cyst)?|author=Anne Elizabeth Laumann|website=Medscape}} Updated: Jun 11, 2020,</ref> | |||
*Fibrous capsule | |||
*Small, cuboidal, dark-staining basal epithelial cells in a palisade arrangement, with no distinct intercellular bridging | |||
*Swollen pale keratinocytes, which increase in height closer to the interior | |||
*Solid eosinophilic-staining keratin | |||
There is no granular cell layer (in contrast to an epidermoid cyst). | |||
===Further workup=== | ===Further workup=== | ||
Look for signs of cyst rupture, which may manifest as inflammation, including granulomas and microabscesses. | Look for signs of cyst rupture, which may manifest as inflammation, including granulomas and microabscesses. | ||
===Microscopic report=== | |||
Example: | |||
{|class=wikitable | |||
| Scalp skin cyst, excision:<br>Ruptured epidermoid cyst. | |||
|} | |||
{{Bottom}} | {{Bottom}} | ||
Revision as of 11:07, 25 September 2021
Author:
Mikael Häggström [note 1]
Generally presents as a skin cyst. Also known as epidermal inclusion cyst (EIC) and sebaceous cyst.
Microscopic evaluation
Typical findings:[1]
- Stratified squamous epithelium with a granular layer
- Cyst wall does not contain eccrine glands, sebaceous glands or hair follicles
- Abundant keratin flakes in cyst lumen
- Often giant cell granuloma in ruptured cysts, similar to foreign body granuloma
Differential diagnosis
Pilomatricoma
The characteristic components of a pilomatricoma include a stroma of fibrovascular connective tissue surrounding irregularly shaped, lobulated islands containing basaloid cells (being darkly stained, round or elongated, with indistinct cell borders and minimal cytoplasm, with nuclei being round to ovoid, deeply basophilic and generally prominent nucleoli), which abruptly or gradually transitions into ghost cells (having abundant, pale, eosinophilic cytoplasm, well defined cell borders and a central clear area, but only only faint traces of nuclear material), which in turn may transition into keratinaceous to amorphous necrosis.[2]
The presence of calcifications with foreign body giant cells is common within pilomatricomas.[3]
Trichilemmal cyst
The constitution of a trichilemmal cyst (also called pilar cyst), from external (top) to internal (bottom):[4]
- Fibrous capsule
- Small, cuboidal, dark-staining basal epithelial cells in a palisade arrangement, with no distinct intercellular bridging
- Swollen pale keratinocytes, which increase in height closer to the interior
- Solid eosinophilic-staining keratin
There is no granular cell layer (in contrast to an epidermoid cyst).
Further workup
Look for signs of cyst rupture, which may manifest as inflammation, including granulomas and microabscesses.
Microscopic report
Example:
| Scalp skin cyst, excision: Ruptured epidermoid cyst. |
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.
Main page
References
- ↑ V. Claire Vaughan, M.D., Joshua Wisell, M.D.. Skin nonmelanocytic tumor - Cysts - Epidermal (epidermoid) type. pathology Outlines. Topic Completed: 9 May 2019. Revised: 13 December 2019
- ↑ Punnya V Angadi (2009-06-01). Skin: Pilomatricoma. Atlas of Genetics and Cytogenetics in Oncology and Haematology.
- ↑ Elder, David E.; Johnson, Bernett L.; Elenitsas, Rosalie, eds (2005). Lever's Histopathology of the Skin . Lippincott Williams & Wilkins. ISBN 978-0-7817-3742-5.Template:Page needed
- ↑ Anne Elizabeth Laumann. Which histologic findings are characteristic of trichilemmal cyst (pilar cyst)?. Medscape. Updated: Jun 11, 2020,
Image sources