Dermal cysts

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Dermal cysts happen and are common. Dermatopathologists can diagnose 'em.

Cysts

Common types:[1]

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

EM, SJS, TEN

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

Erythema multiforme (EM)

Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)

Rx causes of SJS:

  • NSAIDs,
  • anticonvulsants,
  • sulfonamides,
  • penicillins.

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:[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)

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

Gross

  • Have lesions on the knuckle - Gottron's papulle

Histology

  • 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

Feature:

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

Image:

DDx:

  • Dermatofibrosarcoma - if lesion is large.
  • Pilar cyst - no granular layer.

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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