Dermal cysts

Dermal cysts, also skin cysts, are common in dermatopathology. Dermatopathologists can diagnose 'em.

Cysts

Common types:^[1]

Epidermal cyst (sebaceous cyst) -- most common.
Pilar (trichilemmal) cyst.
Dermoid cyst.
Ganglion cyst.
Milicem.

Epidermal necrosis

This may be cystic. It is covered in the epidermal necrosis article, which covers erythema multiforme, Steven-Johnson syndrome and toxic epidermal necrolysis.

Venous lake

General

Dilated vein.

Clinical:

Blanch with pressure.^[2]

Gross

Purple/blue spot.

Images:

Microscopic

Features:^[4]

Lined by endothelium.
Blood in lumen.
+/-Fibrin in lumen.
+/-Solar elastosis - very common.^[5]

DDx:

Angiokeratoma.
- Ectatic superficial dermal vessels.
- Irregular acanthosis.
- Longer rete ridges.
Cherry hemangioma.^[5]

Images:

Venous lake (jhmi.edu).^[3]

Epidermal inclusion cyst

AKA epidermal cyst.

General

Very common.

Microscopic

Features:

Cyst lining has a granular layer - key feature.^[6]
Trapped collagen bundles at edge of lesion with surrounded by fibroblasts.
Keratin.

Image:

DDx:

Pilar cyst - no granular layer.
Eccrine hidrocystoma - eyelid lesion; same histology.^[8]
Dermoid cyst - has adnexal structures, i.e. hair follicle, sebaceous glands, sweat glands.
Dermatofibrosarcoma protuberans - if lesion is large.

Pilar cyst

AKA trichilemmal cyst.

General

Very common.

Gross

Classic location: head ~90%.^[9]

Microscopic

Features:

Keratin.
Cyst lining has no granular layer - key feature.
Trapped collagen bundles at edge of lesion with surrounded by fibroblasts.

DDx:

Epidermal cyst - has a granular layer.

Images:

Steatocystoma

General

Benign.
Typically adults.
Usually on the trunk.
May be genetic; known as steatocystoma multiplex.^[10]
- Classically autosomal dominant.^[11]

Microscopic

Features:^[12]

Cyst lined by squamous epithelium with:
1. Corrugated eosinophilic lining - key feature.
  - Similar appearance to compact keratin (hyperkeratosis).
  - Described as a hyaline cuticle.^[13]
2. No granular cell layer.

Images:

Dermoid cyst

General

Benign.
Congenital choristomas.^[15]
May be found in the ovary.

Microscopic

Features:^[15]^[16]

Cyst lined by normal (keratinized) skin with adnexal structure (hair follicles, sweat glands, sebaceous glands).

DDx:

Epidermal cyst - no adnexal structures.

Images:

Digital mucous cyst

General

Dome-shaped papule.

Microscopic

Features:^[17]

Mucous in superficial dermis - key feature.
No epithelial lining; it is a pseudocyst.

Note:

Mucin = glycolated proteins; may be part of mucous.
Mucous = slippery secretion.
- Some split hairs over the "u" - "mucus" vs. "mucous".^[18]^[19]

DDx:

Focal cutaneous mucinosis.

Images:

Digital mucous cyst (dermpedia.org).^[17]

References

↑ Greenwald, J.; Heng, M. (2007). Toronto Notes for Medical Students 2007 (2007 ed.). The Toronto Notes Inc. for Medical Students Inc.. pp. D5. ISBN 978-0968592878.
↑ URL: http://dermatlas.med.jhmi.edu/derm/IndexDisplay.cfm?ImageID=-969536424. Accessed on: 13 August 2012.
↑ ^3.0 ^3.1 ^3.2 URL: http://dermatlas.med.jhmi.edu/derm/result.cfm?Diagnosis=605386295. Accessed on: 13 August 2012.
↑ Weedon's Skin Pathology. 3rd Ed. P.895.
↑ ^5.0 ^5.1 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 551. ISBN 978-0443066542.
↑ URL: http://emedicine.medscape.com/article/1058907-diagnosis. Accessed on: 18 March 2011.
↑ 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.
↑ 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/.
↑ URL: http://emedicine.medscape.com/article/1058907-overview. Accessed on: 15 April 2012.
↑ Online 'Mendelian Inheritance in Man' (OMIM) 184500
↑ URL: http://path.upmc.edu/cases/case674/dx.html. Accessed on: 29 January 2012.
↑ Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 312. ISBN 978-0443066542.
↑ URL: http://path.upmc.edu/cases/case674/dx.html. Accessed on: 29 January 2012.
↑ URL: http://path.upmc.edu/cases/case674.html. Accessed on: 29 January 2012.
↑ ^15.0 ^15.1 ^15.2 Gandhi N, Syed NA, Alen R. Dermoid Cyst. EyeRounds.org. posted July 26, 2010; Available from: http://www.EyeRounds.org/cases/115-dermoid-cyst.htm. Accessed on: 22 September 2011.
↑ Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 596. ISBN 978-1416054542.
↑ ^17.0 ^17.1 URL: http://www.dermpedia.org/dermpedia-textbook/digital-mucous-myxoid-cyst. Accessed on: 17 January 2012.
↑ URL: http://dictionary.reference.com/browse/mucous. Accessed on: 8 January 2012.
↑ URL: http://dictionary.reference.com/browse/mucus. Accessed on: 8 January 2012.

[Ref_TN2007_D5-1] Greenwald, J.; Heng, M. (2007). Toronto Notes for Medical Students 2007 (2007 ed.). The Toronto Notes Inc. for Medical Students Inc.. pp. D5. ISBN 978-0968592878.

[2] URL: http://dermatlas.med.jhmi.edu/derm/IndexDisplay.cfm?ImageID=-969536424. Accessed on: 13 August 2012.

[jhmi_vl-3] 3.0 ^3.1 ^3.2 URL: http://dermatlas.med.jhmi.edu/derm/result.cfm?Diagnosis=605386295. Accessed on: 13 August 2012.

[4] Weedon's Skin Pathology. 3rd Ed. P.895.

[Ref_Derm551-5] 5.0 ^5.1 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 551. ISBN 978-0443066542.

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

[pmid15728019-7] 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.

[pmid10065300-8] 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/.

[9] URL: http://emedicine.medscape.com/article/1058907-overview. Accessed on: 15 April 2012.

[omim184500-10] Online 'Mendelian Inheritance in Man' (OMIM) 184500

[11] URL: http://path.upmc.edu/cases/case674/dx.html. Accessed on: 29 January 2012.

[Ref_Derm312-12] Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 312. ISBN 978-0443066542.

[13] URL: http://path.upmc.edu/cases/case674/dx.html. Accessed on: 29 January 2012.

[14] URL: http://path.upmc.edu/cases/case674.html. Accessed on: 29 January 2012.

[dc_uiowa-15] 15.0 ^15.1 ^15.2 Gandhi N, Syed NA, Alen R. Dermoid Cyst. EyeRounds.org. posted July 26, 2010; Available from: http://www.EyeRounds.org/cases/115-dermoid-cyst.htm. Accessed on: 22 September 2011.

[Ref_PCPBoD8_596-16] Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 596. ISBN 978-1416054542.

[dermpedia-17] 17.0 ^17.1 URL: http://www.dermpedia.org/dermpedia-textbook/digital-mucous-myxoid-cyst. Accessed on: 17 January 2012.

[18] URL: http://dictionary.reference.com/browse/mucous. Accessed on: 8 January 2012.

[19] URL: http://dictionary.reference.com/browse/mucus. Accessed on: 8 January 2012.

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Dermal cysts

Contents

Cysts

Epidermal necrosis

Venous lake

General

Gross

Microscopic

Epidermal inclusion cyst

General

Microscopic

Pilar cyst

General

Gross

Microscopic

Steatocystoma

General

Microscopic

Dermoid cyst

General

Microscopic

Digital mucous cyst

General

Microscopic

See also

References

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