Inflammatory skin disorders

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Inflammatory skin disorders, also inflammatory skin diseases, are a significant part of dermatopathology. They lead to trepidation among pathologists that don't see lots of skin.

Classification

  • Bullous.
  • Interface.
  • Nodular & diffuse.
  • Spongiotic.
  • Vasculitis.
  • Perivascular.
  • Panniculitis.
  • Psoriasiform.

Tabular comparison of inflammatory skin disease (adapted from Brinster[1]):

Pattern Key histologic feature Subclassifications Example
Bullous "empty space" -subcorneal
-suprabasillar
-subepidermal 		-pemphigus foliaceus
-pemphigus vulgaris
-dermatitis herpetiformis
Interface inflammation at DE junction -vacuolar (minimal)
-lichenoid (band-like) 		-erythema multiforme, SLE
-lichen planus
Nodular & diffuse nodular & diffuse ?
Spongiotic edema between keratinocytes -acute
-subacute
-chronic 		-poison ivy
-nummular dermatitis
-atopic dermatitis
Vasculitis inflammation of vessel wall/vessel was destruction -small vessel
-medium vessel
-large vessel 		-leukocytoclastic vasculitis
-PAN
giant cell arteritis
Perivascular inflammation around vessels ? ?
Panniculitis inflammation of adipose tissue -septal
-nodular 		-erythema nodosum, scleroderma panniculitis
-erythema induratum, infection
Psoriasiform epidermal thickening
and long rete ridges 		-regular
-irregular 		-psoriasis
-lichen simplex chronicus

Notes:

  • DE junction = dermal-epidermal junction.
  • The "empty space" in bullous disease in situ is filled with fluid.

Non-specific patterns

Psoriasiform pattern

General

  • Can be subclassified.

DDx:

  • Psoriasis vulgaris (most common).
  • Psoriatic arthritis.
  • Drug-induced.
  • Others.

Microscopic

Features:[2][1]

  • Regular epidermal thickening - as very long rete ridges (described as "test tube-morphology") - key feature.
    • Epidermis between rete ridges thin ("thinning of suprapapillary plate").
  • Parakeratosis.
  • Thin/absent granular layer.
  • Dilated blood vessels in superficial dermis.
  • Neutrophil clusters (Munro microabscess).

Specific diseases

Seborrheic dermatitis

General

  • Very common.

Microscopic

Features:[3]

  • Spongiosis (epidermal edema).
  • Acanthosis (epidermal thickening).
  • "Follicular lipping" = parakeratosis with neutrophils.
  • Perivascular neutrophils and lymphocytes.

Systemic lupus erythematosus

Main article: Systemic lupus erythematosus

General

  • Systemic disease with multi-organ manifestations.

Microscopic

Features:

  • Lymphocytic interface dermatitis.[4]
  • Basal layer vacuolation.[5]
  • Intradermal mucin.

Dermatomyositis

For the muscle manifestations see: Neuromuscular_pathology#Dermatomyositis.

General

  • Complement mediated disease - membrane attack complex.
  • Usually middle age.
  • Associated skin rash is common.
    • May precede or follow muscle pathology.
  • Associated with malignancy in approximately 10% of cases.[6]

Gross

  • Have lesions on the knuckles - Gottron's papules.

Microsopic

Features:

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

Lichen planus

General

Etiology:

  • Autoimmune disease, T-cell–mediated.[9]

Clinical:[10]

  • 6 Ps: pruritic (itchy), purple, polygonal, planar papules and plaques.

Gross

  • Wickham striae = white lines/dots.
    • Due to hypergranulosis.

Microscopic

Features:[11][12]

  • Loss of basal cells (stratum basale) -- key feature.
  • Loss of rete ridges/formation of pointed rete ridges "sawtoothing".
  • Interface dermatitis (lymphocytes at dermal-epidermal junction).
  • Hypergranulosis; stratum granulosum thickened (grossly seen as "Wickham stria" = white lines).
  • Hyperkeratosis; stratum corneum thickened.
  • Necrotic basal cell in dermis = colloid bodies = Civatte bodies.[13]

DDx:

Notes:

  • Hyperkeratosis and hypergranulosis are not seen in erythema multiforme.
  • Colloid bodies = cytoid bodies = Civatte bodies = hyaline bodies = apoptotic bodies.[14]

Images:

Lichen sclerosus

Main article: Lichen sclerosus

Microscopic

Features:[15]

  • Subepithelial fibrosis - key feature.

Psoriasis

General

Clinical:

  • Auspitz sign = pin-point bleeding on removal of scale.
  • Koebner phenomenon = lesions form at site of trauma.

Microscopic

Features:[16]

  • Acanthosis + long rete ridges - key feature.
  • Parakeratosis.
  • Dilated vessels in superficial dermis (give rise to Auspitz sign).
  • Spongiform pustules = PMNs in stratum spinosum.
  • PMNs in parakeratotic stratum corneum (Munro microabscess).

DDx for pattern

Spongiotic dermatitides

DDx:[1]

  • Atopic dermatitis.
  • Contact dermatitis.
  • Stasis dermatitis.
  • Seborrheic dermatitis.
  • Nummular dermatitis.
  • Spongiotic drug eruption.

Psoriasiform dermatitides

Regular psoriasiform dermatitis

DDx:[1]

  • Psoriasis vulgaris.
  • Dermatophyte infection.
  • Pityriasis rubra pilaris.

Irregular psoriasiform dermatitis

Interface dermatitides

Vacuolar interface dermatitides

DDx:[1]

Others:[1]

Lichenoid interface dermatitides

DDx:[1]

Bullous disease

Subcorneal bullous disorders

DDx with acantholysis:[1]

DDx without acantholysis:DDx:[1]

Suprabasilar bullous disorders

DDx:[1]

Subepidermal bullous disorders

DDx:[1]

Others:

Perivascular inflammation

Lymphocytes

Lymphocytes (tightly cuffed):[1]

  • Infections.
  • Medications.
  • Malignancy.
  • Vitiligo (with absent melanocytes).
  • Scleroderma/morphea.

Lymphocytes & plasma cells +/-eosinophils:

  • Erythema chronicum migrans (Lyme disease).

Lymphocytes (not tightly cuffed):

  • Viral exanthems.
  • Drug eruptions.

Lymphocytes & eosinophils:

  • Drug reaction.
  • Insect bite.
  • Dermatophyte infection.

Neutrophils

DDx:[1]

  • Cellulitis.
  • Neutrophilic eccrine hidradenitis (idiopathic palmar-plantar hidradenitis)

With eosinophils:

  • Urticaria.

Eosinophils

DDx:[1]

  • Hypersensitivity reaction/drug reaction.
  • Insect bite.
  • Bullous pemphigoid, urticarial.

Mast cells

Vasculitis

Main article: Vasculitides

General DDx:

  • Infection.
  • Autoimmune.
  • Malignancy.
  • Toxic (medications).

Small vessel:

Medium vessel:

Medium vessels often with small vessel involvement:

Large vessel:

See also

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Brinster NK (March 2008). "Dermatopathology for the surgical pathologist: a pattern based approach to the diagnosis of inflammatory skin disorders (part I)". Adv Anat Pathol 15 (2): 76–96. doi:10.1097/PAP.0b013e3181664e8d. PMID 18418089.
  2. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1191. ISBN 978-1416031215.
  3. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1191. ISBN 978-1416031215.
  4. ↑ JAH. 20 February 2009.
  5. ↑ 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.
  6. ↑ Chen YJ, Wu CY, Huang YL, Wang CB, Shen JL, Chang YT (2010). "Cancer risks of dermatomyositis and polymyositis: a nationwide cohort study in Taiwan". Arthritis Res. Ther. 12 (2): R70. doi:10.1186/ar2987. PMC 2888225. PMID 20398365. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2888225/.
  7. ↑ Teichman, JM.; Sea, J.; Thompson, IM.; Elston, DM. (Jan 2010). "Noninfectious penile lesions.". Am Fam Physician 81 (2): 167-74. PMID 20082512.
  8. ↑ Gupta, R.; Bansal, B.; Singh, S.; Yadav, I.; Gupta, K.; Kudesia, M. (2009). "Lichen planus of uterine cervix - the first report of a novel site of occurrence: a case report.". Cases J 2: 9306. doi:10.1186/1757-1626-2-9306. PMID 20062629.
  9. ↑ URL: http://emedicine.medscape.com/article/1078327-overview. Accessed on: 11 September 2010.
  10. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1191. ISBN 978-1416031215.
  11. ↑ URL: http://emedicine.medscape.com/article/1078327-overview. Accessed on: 11 September 2010.
  12. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1192. ISBN 978-1416031215.
  13. ↑ 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. 604. ISBN 978-1416054542.
  14. ↑ URL: http://www.careforumwales.org/cell-carcinoma/histopathologic-terminology.html. Accessed on: 28 August 2011.
  15. ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1065-6. ISBN 0-7216-0187-1.
  16. ↑ 16.0 16.1 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. 603. ISBN 978-1416054542.
  17. ↑ URL: http://medical-dictionary.thefreedictionary.com/spondylosis. Accessed on: 28 August 2011.
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