Virus

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This article collects all things virus. The more general topic of infective things is dealt with in microorganisms.

Many virus afflict humans. Only a few of them can be diagnosed histologically.

Viral inclusions - types

Cowdry types:[1]

  • Cowdry type A inclusion:[2]
    • Round eosinophilic material surrounded by a clear halo.
  • Cowdry type B inclusion:[3]
    • Neuropathology thingy. (???)

Images:

Viruses

Herpes simplex virus

  • Abbreviated HSV.

General

Several subtypes:

  • Canker sores - usually HSV-1.
  • Genital herpes - usually HSV-2.

Histology/cytology

Features:[4]

  • Clear "ground glass" nuclei.
    • Rim of peripheral chromatin.
  • Nuclear inclusions.
  • Multinucleation with nuclear molding, i.e. multiple nuclei that touch over a large surface area.

Mnemonic - 3 Ms: Margination, Multinucleation, Molding.

Images:

Cytomegalovirus

  • Abbreviated CMV

General

  • The name comes from the microscopic appearance.

Microscopic

Features:

  • Very large nucleus (as the name implies) with clearing.
  • Granular cytoplasmic inclusions (red on H&E sections).

Notes:

  • Classically in endothelial cells.
    • In the context of esophageal ulcers, it is therefore useful to biopsy the base of the ulcer - if this is suspected.

Images:

IHC

  • IHC for CMV is available - highlights granular cytoplasmic inclusions; increases sensitivity.

Human papilloma virus

  • Abbreviated HPV.

General

Oncocytic types:

  • HPV 18 - predominantly adenocarcinoma.[5]
  • HPV 16 - predominantly squamous cell carcinoma.[5]

Microscopic

Features:

  • Koilocytes:
    • Perinuclear clearing.
    • Nuclear changes.
      • Size similar (or larger) to those in the basal layer of the epithelium.
      • Nuclear enlargement should be evident on low power, i.e. 25x.
      • Central location - nucleus should be smack in the middle of the cell.

Images:

IHC

  • p16 +ve -- stains most cells infected by HPV.

Adenovirus

General

Microscopic

Features:

  • "Smudge" cells[6] - black/blue blob ~ 10-15 micrometers. (???)

Notes:

  • May be morphologically similar to CMV, HSV, VZV inclusions.

Images:

Parvovirus

  • AKA Parvovirus B19.

General

  • Most significant in pregnant women.
    • Parvovirus attacks the nucleated RBCs of the fetus - causes an aplastic anemia.

Trivia:

  • First described in 1975.[8]
    • The "B19" part comes from the label for the specimen.[9]

Microscopic

Features:

  • Glassy (red) nuclear inclusions.[10]
  • Nuclear enlargement.

Images:

Epstein-Barr virus

  • Abbreviated EBV

General

  • Cases mononucleosis.
  • Part of the herpes group of viruses.[13]

Associations

Cancer:[14]

Microscopic

Features:

  • Variable - see specific pathologies in Associations section.
    • +/-Atypical lymphocytes.
    • +/-Hemophagocytosis (uncommon).

See also

References

  1. URL: http://www.pathconsultddx.com/pathCon/largeImage?pii=S1559-8675%2806%2970864-6&figureId=fig3&ecomponentId=mmc3. Accessed: 12 January 2010.
  2. URL: http://www.whonamedit.com/synd.cfm/3495.html. Accessed on: 22 January 2010.
  3. http://www.whonamedit.com/synd.cfm/3496.html. Accessed on: 22 January 2010.
  4. SM. 11 January 2010.
  5. 5.0 5.1 De Boer, MA.; Peters, LA.; Aziz, MF.; Siregar, B.; Cornain, S.; Vrede, MA.; Jordanova, ES.; Fleuren, GJ. (Apr 2005). "Human papillomavirus type 18 variants: histopathology and E6/E7 polymorphisms in three countries.". Int J Cancer 114 (3): 422-5. doi:10.1002/ijc.20727. PMID 15551313.
  6. URL: http://www.pathguy.com/lectures/infect.htm. Accessed on: 8 July 2010.
  7. URL:http://www.medscape.com/viewarticle/438534_2. Accessed on: 8 July 2010.
  8. Cossart, YE.; Field, AM.; Cant, B.; Widdows, D. (Jan 1975). "Parvovirus-like particles in human sera.". Lancet 1 (7898): 72-3. PMID 46024.
  9. Servey JT, Reamy BV, Hodge J (February 2007). "Clinical presentations of parvovirus B19 infection". Am Fam Physician 75 (3): 373–6. PMID 17304869. http://www.aafp.org/afp/991001ap/1455.html.
  10. URL: http://www.pathguy.com/lectures/infect.htm. Accessed on: 8 July 2010.
  11. URL:http://info.fujita-hu.ac.jp/~tsutsumi/case/case210.htm. Accessed on: 8 February 2011.
  12. URL: http://www.scielo.br/scielo.php?pid=S0036-46652007000200007&script=sci_arttext. Accessed on: 18 August 2011.
  13. URL: http://www.meddean.luc.edu/lumen/MedEd/orfpath/herpes.htm. Accessed on: 14 April 2011.
  14. 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. 169. ISBN 978-1416054542.
  15. Jin YK, Xie ZD, Yang S, Lu G, Shen KL (June 2010). "Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis: a retrospective study of 78 pediatric cases in mainland of China". Chin. Med. J. 123 (11): 1426–30. PMID 20819601.