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 ? ?
Perivascular Inflammation around vessels ? ?
Panniculitis Inflamm. of adipose tissue -Septal
-Nodular
-Erythema nodosum
-Erythema induratum
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

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

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 groups

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


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.