Difference between revisions of "Dermal cysts"

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==Pilar cyst==
==Pilar cyst==
*[[AKA]] trichilemmal cyst.
===General===
===General===
*Very common.
*Very common.

Revision as of 17:20, 1 September 2011

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

Cysts

Common types:[1]

EM, SJS, TEN

  • SJS and TEN are on a spectrum, EM is considered separate.

Erythema multiforme

  • Abbreviated EM.

General

Features:[2]

  • Hypersensitivity disorder to a drug or infections.
    • Associated with the following: HSV, Mycoplasma, Histoplasma, others.

Clinical:

  • Target-like lesion.

Microscopic

Features:[2]

  • Lymphocytic interface dermatitis (lymphocytes at the dermal-epidermal junction).
  • Necrotic/degenerative keratinocytes - key feature.
  • +/-Epidermal blistering.
  • +/-Epidermal sloughing.

Stevens-Johnson Syndrome

  • Abbreviated SJS.

Rx causes of SJS:

  • NSAIDs.
  • Anticonvulsants.
  • Sulfonamides.
  • Penicillins.

Toxic Epidermal Necrolysis

  • Abbreviated TEN.

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.

Venous lake

  • Dilated vein.

Microscopic

Features:[3]

  • 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:[4][5]

  • 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.[6]
  • Basal layer vacuolation.[7]

Familial benign pemphigus

  • AKA Hailey-Hailey disease. Was described by two brothers - that's why it is Hailey-Hailey.[8]

Etiology

  • Autosomal dominant with incomplete penetration.[8]
  • Desmosomal defect - due to mutation in the gene ATP2C1.[8]

Clinical

  • Chest.
  • Intriginous regions (?sp).
  • Typically presents individual in their 30s and 40s.[8]

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.[9]
  • 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. ↑ 2.0 2.1 Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1189. ISBN 978-1416031215.
  3. ↑ Weedon's Skin Pathology. 3rd Ed. P.895.
  4. ↑ URL: http://www.dermatologyoutlines.com/dermskintumornonmelanocytic.html#collagenousfibroma. Accessed on: 19 March
  5. ↑ 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.
  6. ↑ JAH. 20 February 2009.
  7. ↑ 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.
  8. ↑ 8.0 8.1 8.2 8.3 http://emedicine.medscape.com/article/1063224-overview
  9. ↑ URL: http://emedicine.medscape.com/article/1058907-diagnosis. Accessed on: 18 March 2011.
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