Kaposi sarcoma

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Kaposi sarcoma, abbreviated KS, is an uncommon vascular tumour that is often associated with HIV/AIDS.

Kaposi sarcoma
Diagnosis in short

Kaposi sarcoma. H&E stain.

LM vascular lesion (abundant RBCs), +/-"promontory sign", +/-spindle cells with minimal nuclear atypia, RBC extravasation, +/-intracytoplasmic hyaline globules, +/-hemosiderin deposits, +/-plasma cells
Subtypes classic, endemic, immunosuppression-associated or transplant-associated, AIDS-associated
LM DDx angiosarcoma, Masson's hemangioma (intravascular papillary endothelial hyperplasia), benign lymphangioendothelioma
IHC HHV-8 +ve, CD31 +ve ,CD34 +ve
Site skin, others

Associated Dx +/-HIV infection or immunoincompentence
Prevalence uncommon
Prognosis dependent on subtype

General

  • Caused by Human herpesvirus-8 (HHV-8).
  • In the North American context, it is often associated with immunodeficiency, e.g. HIV/AIDS.

Interesting note:

  • It has been said that KS is not really a sarcoma.[1]

Stages

It is seen in different stages:[2][3]

  1. Patch stage.
  2. Plaque stage.
  3. Nodular stage.
  4. Exophytic stage.
  5. Infiltrative stage.
  6. Lymphadenopathic stage.

Note:

  • The first three are the classic ones.

Type or form

Classically divided into four types:[4][5][6]

  • Classic = old men Mediterranean or Ashkenazi Jew.
  • Endemic = African infants and young males.
  • Immunosuppression-associated or transplant-associated - iatrogenic.
  • AIDS-associated.

Microscopic

Features:[7]

  • Vascular lesion (abundant RBCs) with:
    • +/-"Promontory sign" - small vessel protruding into an abnormal vascular space.[8]
      • Not pathognomonic for KS.[9]
    • +/-Spindle cells with minimal nuclear atypia.
    • RBC extravasation - very useful - important feature.[10]
  • +/-Intracytoplasmic hyaline globules - uncommon - one usu. needs to search for 'em.[11]
    • Pale pink globs (that are paler than RBCs) - important feature.
  • +/-Hemosiderin deposits.
  • +/-Plasma cells.[12]

Notes:

DDx:

  • Angiosarcoma - have many mitoses, nuclear atypia, RBC extravasation not common.
  • Masson's hemangioma - AKA intravascular papillary endothelial hyperplasia.
  • Benign lymphangioendothelioma.[13]
    • Histologically very similar.[14]

Images

www:

Stains

  • PAS +ve -- hyaline globules.

IHC

  • CD31 +ve.
  • CD34 +ve.
  • HHV-8 +ve.

See also

References

  1. Pérez, A.; Sánchez, JL.; Almodóvar, PI. (Oct 2003). "Kaposi's sarcoma is not a neoplasm let alone a sarcoma.". Int J Dermatol 42 (10): 844-5. PMID 14521707.
  2. URL: http://www.histopathology-india.net/KS.htm. Accessed on: 31 January 2010.
  3. URL: http://emedicine.medscape.com/article/1083998-clinical#a0217. Accessed on: 17 November 2011.
  4. Szajerka, T.; Jablecki, J.. "Kaposi's sarcoma revisited.". AIDS Rev 9 (4): 230-6. PMID 18219366.
  5. Morand, JJ.; Lightburn, E.; Simon, F.; Patte, JH. (Apr 2007). "[Update on Kaposi's sarcoma].". Med Trop (Mars) 67 (2): 123-30. PMID 17691428.
  6. Antman, K.; Chang, Y. (Apr 2000). "Kaposi's sarcoma.". N Engl J Med 342 (14): 1027-38. doi:10.1056/NEJM200004063421407. PMID 10749966.
  7. Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 23. ISBN 978-1416002741.
  8. Lazova R, McNiff JM, Glusac EJ, Godic A (April 2009). "Promontory sign--present in patch and plaque stage of angiosarcoma!". Am J Dermatopathol 31 (2): 132–6. doi:10.1097/DAD.0b013e3181951045. PMID 19318797.
  9. Fernandez-Flores A, Rodriguez R (June 2010). "Promontory Sign in a Reactive Benign Vascular Proliferation". Am J Dermatopathol. doi:10.1097/DAD.0b013e3181cf0ae5. PMID 20577080.
  10. Kato, H.; Hamada, T.; Tsuji, T.; Baba, T.; Seki, J.; Kobayashi, Y. (Jul 1990). "Kaposi's sarcoma: a light and electron microscopic study.". J Dermatol 17 (7): 414-22. PMID 2229644.
  11. 11.0 11.1 del Rosario AD, Bui HX, Singh J, Ginsburg R, Ross JS (December 1994). "Intracytoplasmic eosinophilic hyaline globules in cartilaginous neoplasms: a surgical, pathological, ultrastructural, and electron probe x-ray microanalytic study". Hum. Pathol. 25 (12): 1283–9. PMID 7528163.
  12. Douglas, JL.; Gustin, JK.; Dezube, B.; Pantanowitz, JL.; Moses, AV. (Sep 2007). "Kaposi's sarcoma: a model of both malignancy and chronic inflammation.". Panminerva Med 49 (3): 119-38. PMID 17912148.
  13. Guillou, L.; Fletcher, CD. (Aug 2000). "Benign lymphangioendothelioma (acquired progressive lymphangioma): a lesion not to be confused with well-differentiated angiosarcoma and patch stage Kaposi's sarcoma: clinicopathologic analysis of a series.". Am J Surg Pathol 24 (8): 1047-57. PMID 10935645.
  14. URL: http://path.upmc.edu/cases/case134/dx.html. Accessed on: 5 January 2012.