Difference between revisions of "Dermal cysts"

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(split-out EM, SJS, TEN)
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==Epidermal necrosis==
==Epidermal necrosis==
===General===
*This may be cystic. It is covered in the ''[[epidermal necrosis]]'' article, which covers [[erythema multiforme]], [[Steven-Johnson syndrome]] and [[toxic epidermal necrolysis]].
Full thickness DDx:
*Erythema multiform (EM).
*Toxic epidermal necrolysis (TEN).
*Stevens-Johnson syndrome (SJS).
*Trauma.
*Others. (???)
 
Partial thickness DDx:
*Staphylococcal scalded skin syndrome.
*Trauma. (???)
*Others. (???)
 
Notes:
*SJS and TEN are on a spectrum, EM (depending on who you ask) is considered separate.
 
===Erythema multiforme===
*Abbreviated ''EM''.
====General====
Features:<ref name=Ref_PBoD8_1189>{{Ref PBoD8|1189}}</ref>
*Hypersensitivity disorder due to a drug ''or'' infection.
**Associated with the following: [[HSV]], Mycoplasma, [[Histoplasma]], others.
 
Clinical:
*Target-like lesion.
 
====Microscopic====
Features:<ref name=Ref_PBoD8_1189>{{Ref PBoD8|1189}}</ref>
*Lymphocytic interface dermatitis (lymphocytes at the dermal-epidermal junction).
*Necrotic/degenerative keratinocytes - '''key feature'''.
*+/-Epidermal blistering.
*+/-Epidermal sloughing.
 
===Stevens-Johnson Syndrome===
*Abbreviated SJS.
====General====
Rx causes of SJS:
*NSAIDs.
*Anticonvulsants.
*Sulfonamides.
*Penicillins.
 
====Microscopic====
Features:
*Similar [[erythema multiforme]].
 
===Toxic epidermal necrolysis===
*Abbreviated TEN.
====General====
*TEN more severe form SJS.
 
Definition:
*>30% sheet-like epidermal detachment, diffuse erythema, severe mucous membrane involvement.
*Most TEN (80%) Rx-related, only 50% of SJS Rx-related.
 
====Microscopic====
Features:
*Like [[erythema multiforme]] - but usu. less inflammation.<ref>S. Sade. 8 September 2011.</ref>


==Venous lake==
==Venous lake==

Revision as of 15:36, 9 September 2011

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

Cysts

Common types:[1]

Epidermal necrosis

Venous lake

  • Dilated vein.

Microscopic

Features:[2]

  • Lined by endothelium.
  • Blood in lumen.
  • +/-Fibrin in lumen.

DDx:

  • Angiokeratoma.
    • Ectatic superficial dermal vessels.
    • Irregular acanthosis.
    • Longer rete ridges.

Neurofibromatosis (von Recklinghausen's disease)

Main article: Neurofibromatosis

Etiology

  • Genetic - autosomal dominant disorder.

Management

  • Follow for malignant transformation of neurofibroma --> neurofibrosarcoma.

Treatment

  • Excise suspicious lesions & lesions that are painful.

Collagenous fibroma

General

  • Benign.
  • Used to be known as desmoplastic fibroblastoma.

Epidemiology:

  • May be on the lip.

Microscopic

Features:[3][4]

  • Acellular stroma with abundant collagen.

Notes:

  • No nuclear atypia.

Dermatomyositis

See: Neuromuscular_pathology#Dermatomyositis.

Gross

  • Have lesions on the knuckle - Gottron's papulle

Microsopic

Features:

  • Lymphocytic interface dermatitis (inflammation at the dermal-epidermal junction).
  • Loss of rete ridges.

Systemic lupus erythematosus

  • Lymphocytic interface dermatitis.[5]
  • Basal layer vacuolation.[6]

Familial benign pemphigus

  • AKA Hailey-Hailey disease. Was described by two brothers - that's why it is Hailey-Hailey.[7]

Etiology

  • Autosomal dominant with incomplete penetration.[7]
  • Desmosomal defect - due to mutation in the gene ATP2C1.[7]

Clinical

  • Chest.
  • Intriginous regions (?sp).
  • Typically presents individual in their 30s and 40s.[7]

Histology

  • Hair folicles spared.
  • Epidermis thickened.

DDx

  • May resemble pemphigus vulgaris.

Epidermal inclusion cyst

  • AKA epidermal cyst.

General

  • Very common.

Microscopic

Features:

  • Cyst lining has a granular layer - key feature.[8]
  • Trapped collagen bundles at edge of lesion with surrounded by fibroblasts.
  • Keratin.

Image:

DDx:

Pilar cyst

  • AKA trichilemmal cyst.

General

  • Very common.

Microscopic

Features:

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

DDx:

See also

References

  1. ↑ TN07 D5
  2. ↑ Weedon's Skin Pathology. 3rd Ed. P.895.
  3. ↑ URL: http://www.dermatologyoutlines.com/dermskintumornonmelanocytic.html#collagenousfibroma. Accessed on: 19 March
  4. ↑ Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 161. ISBN 978-0781740517.
  5. ↑ JAH. 20 February 2009.
  6. ↑ Crowson AN, Magro CM, Mihm MC (April 2008). "Interface dermatitis". Arch. Pathol. Lab. Med. 132 (4): 652–66. PMID 18384217. http://www.archivesofpathology.org/doi/full/10.1043/1543-2165%282008%29132%5B652%3AID%5D2.0.CO%3B2.
  7. ↑ 7.0 7.1 7.2 7.3 http://emedicine.medscape.com/article/1063224-overview
  8. ↑ URL: http://emedicine.medscape.com/article/1058907-diagnosis. Accessed on: 18 March 2011.
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