What are the types of Kaposi sarcoma (KS)?

Updated: Apr 11, 2019
  • Author: Jessica Katz, MD, PhD, FACP; Chief Editor: Edwin Choy, MD, PhD  more...
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Answer

Kaposi sarcoma (KS) was described initially in 1872 by a Hungarian dermatologist, Moritz Kaposi. The lesions are characterized by proliferation of spindle cells of endothelial origin, with varying degrees of abnormal vascularity, inflammatory infiltrates, and fibrosis. Red cells and hemosiderin deposits give lesions their characteristic purplish color. Spindle cells are infected with HHV-8. HHV-8 encodes a number of genes that induce proliferation, cytokine production, and angiogenesis and thereby contribute to pathogenesis.

Kaposi sarcoma follows a variable clinical course, ranging from minimal mucocutaneous disease to extensive organ involvement. See the table below. [1]

Types of Kaposi sarcoma (Open Table in a new window)

Classification

Affected Population

Clinical Course

AIDS related

HIV-infected persons (usually those with a low CD4+ count usually) 

Most aggressive (survival improved with antiretroviral therapy)

Classical

Eastern European or Mediterranean men

Indolent (progression over years to decades)

Endemic

Subsaharan African children and adults

Somewhat aggressive

Iatrogenic

Patients receiving immunosuppressive therapy (eg, following organ transplantation, for autoimmune disease)

Somewhat aggressive

Adapted from Antman K, Chang Y. Kaposi's sarcoma. N Engl J Med. 2000 Apr 6. 342 (14):1027-38.[Medline].

The common theme of immune dysregulation is associated with all 4 types of Kaposi sarcoma. Diminished responsiveness of cytotoxic T-lymphocytes is associated with Kaposi sarcoma pathogenesis. [15]  Restoration of natural killer cell cytoxic effect may explain regression of Kaposi sarcoma in AIDS patients treated with antiretrovirla therapy. [16] Immune activation may also be a factor in Kaposi sarcoma, with a role for inflammatory cytokines such as gamma interferon and the initiation of HHV-8 infected cell proliferation by HIV-tat protein. [17, 18] This complex interaction of HIV, HHV-8, environmental factors, and the immune system requires further investigation to attempt to decipher the true pathogenesis of Kaposi sarcoma.


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