Difference between revisions of "Epidermal inclusion cyst"

Epidermal inclusion cyst
	Diagnosis in short
	; Epidermal inclusion cyst. H&E stain.
LM	cyst lining by a stratified squamous epithelium with a granular layer - contains keratin; no significant nuclear atypia; +/-granulomatous inflammation (due to rupture)
LM DDx	pilar cyst, eccrine hidrocystoma (eyelid), dermoid cyst, cystic squamous cell carcinoma, keratoacanthoma, dermatofibrosarcoma protuberans, hybrid epidermoid and trichilemmal cyst
Gross	nodule +/-yellow colour
Site	skin
Prevalence	very common
Prognosis	benign
Clin. DDx	other skin cysts, gouty tophus

Latest revision as of 13:32, 29 December 2016

Epidermal inclusion cyst, abbreviated EIC, is a very common skin pathology. It is also know as epidermal cyst, epidermoid cyst,^[1] and follicular cyst, infundibular type.

Testicular epidermoid cyst is dealt with separately in epidermoid cyst of the testis.

General

Very common.
The clinical term is sebaceous cyst.
- This is a misnomer as they contain keratin (not sebum).^[2]^[3]
- The term may be used to refer to a pilar cyst.

Gross

Features:^[4]

Nodule.
+/-Yellowish colour.

DDx:

Pilar cyst - indistinguishable on gross.^[2]
Melanoma.^[3]
Gouty tophus.

Image

Epidermal inclusion cyst. (WC)

Microscopic

Features:

Cyst lining by a stratified squamous epithelium with a granular layer - key feature.^[5]
- No significant nuclear atypia.
- Contains keratin - acellular, lamellar appearance.
+/-Granulomatous inflammation due to rupture.

DDx:

Pilar cyst - no granular layer.
Eccrine hidrocystoma - eyelid lesion; same histology.^[6]
Dermoid cyst - has adnexal structures, i.e. hair follicle, sebaceous glands, sweat glands.
Cystic squamous cell carcinoma.^[7]
Keratoacanthoma.^[1]
Dermatofibrosarcoma protuberans - if lesion is large.
Hybrid epidermoid and trichilemmal cyst.^[8]

Images

EIC - intermed. mag. (WC)
EIC - high mag. (WC)
EIC - very high mag. (WC)

Dermoid cyst - intracranial. (WC)

www:

Sign out

SKIN CYST, BACK, EXCISION: 
- EPIDERMAL INCLUSION CYST.

Ruptured

Lesion, Left Elbow, Excision:
- Benign epidermal inclusion cyst with evidence of rupture.

Block letters

SKIN LESION, RIGHT CHEEK, EXCISION:
- RUPTURED EPIDERMAL INCLUSION CYST.

Overlying skin

SKIN LESION (QUERY CYST), RIGHT JAW, EXCISION:
- EPIDERMAL INCLUSION CYST.
- BENIGN (OVERLYING) SKIN WITH SOLAR ELASTOSIS.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.

Not quite a cyst

"CYST", LEFT INDEX FINGER, EXCISION:
- LARGE (CYST-LIKE) EPIDERMAL INVAGINATION CONTAINING KERATIN.
- DERMAL SCAR.
- MINIMAL (NONSPECIFIC) PERIVASCULAR INFLAMMATION.
- NO DEFINITE CYST APPARENT.
- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.

Micro

The sections show hair-bearing skin with a cyst that is lined by squamous epithelium with a granular layer. The cyst contains keratin. The overlying epithelium is unremarkable.

Ruptured

The sections show hair-bearing skin with a cyst that is lined by squamous epithelium with a granular layer. The cyst contains keratin. A mixed inflammatory infiltrate (predominantly lymphocytes and plasma cells) surround the cyst. Neutrophils infiltrate the cyst lining and are admixed with the keratin within its core.

The lesion appears to be completely excised in the plane of section. Hair follicles are adjacent to the lesion; however, they are not inflamed. The overlying epithelium is unremarkable.

Ruptured without epithelium

The section shows a dermal collection of neutrophils with acellular keratin-like material surrounded by histiocytes and fibrosis. The lesion is completely excised in the plane of section. Hair follicles are adjacent to the abscess; however, they are not inflamed.

References

↑ ^1.0 ^1.1 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 302. ISBN 978-0443066542.
↑ ^2.0 ^2.1 URL: http://www.dermis.net/dermisroot/en/36946/diagnose.htm. Accessed on: 2 November 2012.
↑ ^3.0 ^3.1 Venus, MR.; Eltigani, EA.; Fagan, JM. (Sep 2007). "Just another sebaceous cyst?". Ann R Coll Surg Engl 89 (6): W19-21. doi:10.1308/147870807X227791. PMC 2121251. PMID 18201468. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2121251/..
↑ URL: http://dermatlas.med.jhmi.edu/derm/result.cfm?diagnosis=128. Accessed on: 2 November 2012.
↑ URL: http://emedicine.medscape.com/article/1058907-diagnosis. Accessed on: 18 March 2011.
↑ Adams, SP. (Feb 1999). "Dermacase. Eccrine hydrocystoma.". Can Fam Physician 45: 297, 306. PMC 2328272. PMID 10065300. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2328272/.
↑ Lin, CY.; Jwo, SC. (Apr 2002). "Squamous cell carcinoma arising in an epidermal inclusion cyst.". Chang Gung Med J 25 (4): 279-82. PMID 12079164.
↑ Brownstein, MH. (Dec 1983). "Hybrid cyst: a combined epidermoid and trichilemmal cyst.". J Am Acad Dermatol 9 (6): 872-5. PMID 6643785.
↑ Crystal, P.; Shaco-Levy, R. (Mar 2005). "Concentric rings within a breast mass on sonography: lamellated keratin in an epidermal inclusion cyst.". AJR Am J Roentgenol 184 (3 Suppl): S47-8. PMID 15728019.

[Ref_Derm302-1] 1.0 ^1.1 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 302. ISBN 978-0443066542.

[dermis36946-2] 2.0 ^2.1 URL: http://www.dermis.net/dermisroot/en/36946/diagnose.htm. Accessed on: 2 November 2012.

[pmid18201468-3] 3.0 ^3.1 Venus, MR.; Eltigani, EA.; Fagan, JM. (Sep 2007). "Just another sebaceous cyst?". Ann R Coll Surg Engl 89 (6): W19-21. doi:10.1308/147870807X227791. PMC 2121251. PMID 18201468. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2121251/..

[4] URL: http://dermatlas.med.jhmi.edu/derm/result.cfm?diagnosis=128. Accessed on: 2 November 2012.

[5] URL: http://emedicine.medscape.com/article/1058907-diagnosis. Accessed on: 18 March 2011.

[pmid10065300-6] Adams, SP. (Feb 1999). "Dermacase. Eccrine hydrocystoma.". Can Fam Physician 45: 297, 306. PMC 2328272. PMID 10065300. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2328272/.

[pmid12079164-7] Lin, CY.; Jwo, SC. (Apr 2002). "Squamous cell carcinoma arising in an epidermal inclusion cyst.". Chang Gung Med J 25 (4): 279-82. PMID 12079164.

[pmid6643785-8] Brownstein, MH. (Dec 1983). "Hybrid cyst: a combined epidermoid and trichilemmal cyst.". J Am Acad Dermatol 9 (6): 872-5. PMID 6643785.

[pmid15728019-9] Crystal, P.; Shaco-Levy, R. (Mar 2005). "Concentric rings within a breast mass on sonography: lamellated keratin in an epidermal inclusion cyst.". AJR Am J Roentgenol 184 (3 Suppl): S47-8. PMID 15728019.

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@@ Line 1: / Line 1: @@
-#redirect [[Dermal_cysts#Epidermal_inclusion_cyst]]
+{{ Infobox diagnosis
+| Name       = {{PAGENAME}}
+| Image      = Epidermal_inclusion_cyst_--_high_mag.jpg
+| Width      =
+| Caption    = Epidermal inclusion cyst. [[H&E stain]].
+| Micro      = cyst lining by a stratified squamous epithelium with a granular layer - contains keratin; no significant nuclear atypia; +/-[[granuloma|granulomatous inflammation]] (due to rupture)
+| Subtypes   =
+| LMDDx      = [[pilar cyst]], [[eccrine hidrocystoma]] (eyelid), [[dermoid cyst]], cystic [[squamous cell carcinoma of the skin|squamous cell carcinoma]], [[keratoacanthoma]], [[dermatofibrosarcoma protuberans]], hybrid epidermoid and trichilemmal cyst
+| Stains     =
+| IHC        =
+| EM         =
+| Molecular  =
+| IF         =
+| Gross      = nodule +/-yellow colour
+| Grossing   =
+| Site       = [[skin]]
+| Assdx      =
+| Syndromes  =
+| Clinicalhx =
+| Signs      =
+| Symptoms   =
+| Prevalence = very common
+| Bloodwork  =
+| Rads       =
+| Endoscopy  =
+| Prognosis  = benign
+| Other      =
+| ClinDDx    = other [[skin cysts]], [[gouty tophus]]
+}}
+'''Epidermal inclusion cyst''', abbreviated '''EIC''', is a very common [[skin]] pathology. It is also know as '''epidermal cyst''', '''epidermoid cyst''',<ref name=Ref_Derm302>{{Ref Derm|302}}</ref> and '''follicular cyst, infundibular type'''.
+''Testicular epidermoid cyst'' is dealt with separately in ''[[epidermoid cyst of the testis]]''.
+==General==
+*Very common.
+*The clinical term is ''[[sebaceous cyst]]''.
+**This is a misnomer as they contain keratin (not sebum).<ref name=dermis36946>URL: [http://www.dermis.net/dermisroot/en/36946/diagnose.htm http://www.dermis.net/dermisroot/en/36946/diagnose.htm]. Accessed on: 2 November 2012.</ref><ref name=pmid18201468>{{Cite journal  | last1 = Venus | first1 = MR. | last2 = Eltigani | first2 = EA. | last3 = Fagan | first3 = JM. | title = Just another sebaceous cyst? | journal = Ann R Coll Surg Engl | volume = 89 | issue = 6 | pages = W19-21 | month = Sep | year = 2007 | doi = 10.1308/147870807X227791 | PMID = 18201468 | PMC = 2121251 }}.</ref>
+**The term may be used to refer to a [[pilar cyst]].
+==Gross==
+Features:<ref>URL: [http://dermatlas.med.jhmi.edu/derm/result.cfm?diagnosis=128 http://dermatlas.med.jhmi.edu/derm/result.cfm?diagnosis=128]. Accessed on: 2 November 2012.</ref>
+*[[Nodule]].
+*+/-Yellowish colour.
+DDx:
+*[[Pilar cyst]] - indistinguishable on gross.<ref name=dermis36946>URL: [http://www.dermis.net/dermisroot/en/36946/diagnose.htm http://www.dermis.net/dermisroot/en/36946/diagnose.htm]. Accessed on: 2 November 2012.</ref>
+*[[Melanoma]].<ref name=pmid18201468/>
+*[[Gouty tophus]].
+===Image===
+<gallery>
+Image:Inflamed_epidermal_inclusion_cyst.jpg |Epidermal inclusion cyst. (WC)
+</gallery>
+==Microscopic==
+Features:
+*Cyst lining by a stratified squamous epithelium with a granular layer - '''key feature'''.<ref>URL: [http://emedicine.medscape.com/article/1058907-diagnosis http://emedicine.medscape.com/article/1058907-diagnosis]. Accessed on: 18 March 2011.</ref>
+**No significant nuclear atypia.
+**Contains keratin - acellular, lamellar appearance.
+*+/-[[granuloma|Granulomatous inflammation]] due to rupture.
+DDx:
+*[[Pilar cyst]] - no granular layer.
+*[[Eccrine hidrocystoma]] - eyelid lesion; same histology.<ref name=pmid10065300>{{Cite journal  | last1 = Adams | first1 = SP. | title = Dermacase. Eccrine hydrocystoma. | journal = Can Fam Physician | volume = 45 | issue =  | pages = 297, 306 | month = Feb | year = 1999 | doi =  | PMID = 10065300 |PMC = 2328272 }}</ref>
+*[[Dermoid cyst]] - has adnexal structures, i.e. hair follicle, sebaceous glands, sweat glands.
+*Cystic [[squamous cell carcinoma of the skin|squamous cell carcinoma]].<ref name=pmid12079164>{{Cite journal  | last1 = Lin | first1 = CY. | last2 = Jwo | first2 = SC. | title = Squamous cell carcinoma arising in an epidermal inclusion cyst. | journal = Chang Gung Med J | volume = 25 | issue = 4 | pages = 279-82 | month = Apr | year = 2002 | doi =  | PMID = 12079164 }}</ref>
+*[[Keratoacanthoma]].<ref name=Ref_Derm302>{{Ref Derm|302}}</ref>
+*[[Dermatofibrosarcoma protuberans]] - if lesion is large.
+*Hybrid epidermoid and trichilemmal cyst.<ref name=pmid6643785>{{Cite journal  | last1 = Brownstein | first1 = MH. | title = Hybrid cyst: a combined epidermoid and trichilemmal cyst. | journal = J Am Acad Dermatol | volume = 9 | issue = 6 | pages = 872-5 | month = Dec | year = 1983 | doi =  | PMID = 6643785 }}</ref>
+===Images===
+<gallery>
+Image: Epidermal inclusion cyst -- intermed mag.jpg | EIC - intermed. mag. (WC)
+Image: Epidermal inclusion cyst -- high mag.jpg | EIC - high mag. (WC)
+Image: Epidermal inclusion cyst -- very high mag.jpg | EIC - very high mag. (WC)
+</gallery>
+<gallery>
+Image:Dermoid cyst intracranial.jpg | Dermoid cyst - intracranial. (WC)
+</gallery>
+www:
+*[http://www.flickr.com/photos/euthman/5517587941/in/photostream/ Epidermal inclusion cyst (flickr.com)].
+*[http://www.ajronline.org/content/184/3_supp/S47/F4.expansion.html Epidermal inclusion cyst (ajronline.org)].<ref name=pmid15728019>{{Cite journal  | last1 = Crystal | first1 = P. | last2 = Shaco-Levy | first2 = R. | title = Concentric rings within a breast mass on sonography: lamellated keratin in an epidermal inclusion cyst. | journal = AJR Am J Roentgenol | volume = 184 | issue = 3 Suppl | pages = S47-8 | month = Mar | year = 2005 | doi =  | PMID = 15728019 |URL = http://www.ajronline.org/cgi/pmidlookup?view=long&pmid=15728019}}</ref>
+*[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2627164/figure/F1/ Ruptured epidermal inclusion cyst (nih.gov)].
+==Sign out==
+<pre>
+SKIN CYST, BACK, EXCISION:
+- EPIDERMAL INCLUSION CYST.
+</pre>
+===Ruptured===
+<pre>
+Lesion, Left Elbow, Excision:
+- Benign epidermal inclusion cyst with evidence of rupture.
+</pre>
+====Block letters====
+<pre>
+SKIN LESION, RIGHT CHEEK, EXCISION:
+- RUPTURED EPIDERMAL INCLUSION CYST.
+</pre>
+===Overlying skin===
+<pre>
+SKIN LESION (QUERY CYST), RIGHT JAW, EXCISION:
+- EPIDERMAL INCLUSION CYST.
+- BENIGN (OVERLYING) SKIN WITH SOLAR ELASTOSIS.
+- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
+</pre>
+===Not quite a cyst===
+<pre>
+"CYST", LEFT INDEX FINGER, EXCISION:
+- LARGE (CYST-LIKE) EPIDERMAL INVAGINATION CONTAINING KERATIN.
+- DERMAL SCAR.
+- MINIMAL (NONSPECIFIC) PERIVASCULAR INFLAMMATION.
+- NO DEFINITE CYST APPARENT.
+- NEGATIVE FOR DYSPLASIA AND NEGATIVE FOR MALIGNANCY.
+</pre>
+===Micro===
+The sections show hair-bearing skin with a cyst that is lined by squamous epithelium with a granular layer.  The cyst contains keratin. The overlying epithelium is unremarkable.
+====Ruptured====
+The sections show hair-bearing skin with a cyst that is lined by squamous epithelium with a granular layer. The cyst contains keratin. A mixed inflammatory infiltrate (predominantly lymphocytes and plasma cells) surround the cyst. Neutrophils infiltrate the cyst lining and are admixed with the keratin within its core.
+The lesion appears to be completely excised in the plane of section.  Hair follicles are adjacent to the lesion; however, they are not inflamed. The overlying epithelium is unremarkable.
+====Ruptured without epithelium====
+The section shows a dermal collection of neutrophils with acellular keratin-like material surrounded by histiocytes and fibrosis.  The lesion is completely excised in the plane of section.  Hair follicles are adjacent to the abscess; however, they are not inflamed.
+==See also==
+*[[Dermal cysts]].
+*[[Epidermoid cyst of the testis]].
+*[[Cholesteatoma]].
+==References==
+{{Reflist|2}}
+[[Category:Dermal cysts]]

Difference between revisions of "Epidermal inclusion cyst"

Latest revision as of 13:32, 29 December 2016

Contents

General

Gross

Image

Microscopic

Images

Sign out

Ruptured

Block letters

Overlying skin

Not quite a cyst

Micro

Ruptured

Ruptured without epithelium

See also

References

Navigation menu

Search

Epidermal inclusion cyst
Diagnosis in short
Epidermal inclusion cyst. H&E stain.

LM	cyst lining by a stratified squamous epithelium with a granular layer - contains keratin; no significant nuclear atypia; +/-granulomatous inflammation (due to rupture)
LM DDx	pilar cyst, eccrine hidrocystoma (eyelid), dermoid cyst, cystic squamous cell carcinoma, keratoacanthoma, dermatofibrosarcoma protuberans, hybrid epidermoid and trichilemmal cyst
Gross	nodule +/-yellow colour
Site	skin

Prevalence	very common
Prognosis	benign
Clin. DDx	other skin cysts, gouty tophus