What is Kaposi sarcoma (KS)?

Updated: Mar 26, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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In 1872, Moritz Kaposi (1837-1902) of Kaposvar, Hungary, a dermatology faculty member at the University of Vienna, first described idiopathisches multiples Pigmentsarkom der Haut, which has become known as Kaposi sarcoma (KS). Kaposi sarcoma had brownish red–to–bluish red cutaneous nodules that tended to enlarge into dome-shaped tumors. Kaposi observed similar neoplasms of the mucosa, especially of the larynx, trachea, stomach, liver, and colon. Kaposi's original 1872 description of 5 patients is more similar to the Kaposi sarcoma seen in AIDS (KS-AIDS) than the Kaposi sarcoma expected in elderly men of Italian, Jewish, or Mediterranean linkage, in whom the disease behavior is benign. Kaposi's original 5 patients died within 2-3 years. Kaposi later updated his data, noting that all of his 16 patients were men with a prognosis that remained unfavorable.

In 1882, Tommaso De Amici, Professor and Head, Dermatology, University of Naples, Italy published in monograph form a detailed analysis of 12 patients with Kaposi sarcoma. [1, 2]

For most of the first 3 quarters of the 20th century, Kaposi sarcoma was viewed as an indolent slowly growing cancer, and patients were expected to die with, rather than of, Kaposi sarcoma. The aggressive course originally noted by Kaposi has become part of the devastation of AIDS, especially among men who are homosexual. [3, 4]

In 1981, KS-AIDS in America was identified in 3 reports of Kaposi sarcoma as an original defining element of what later became known as AIDS (plus an important editorial and a Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report bulletin). These original descriptions were by Borkovic and Schwartz in San Francisco, Friedman-Kien from New York City, [5] and Gottlieb and associates in Los Angeles. [6] For some time, Kaposi sarcoma was seen in 30-40% of patients with AIDS, often as the presenting sign. The incidence of Kaposi sarcoma has fallen markedly in recent times, although its prevalence has not. The challenge remained to explain the reason patients who are homosexual and have AIDS exhibited Kaposi sarcoma much more commonly than did patients with AIDS unassociated with homosexuality, with the exception of small foci of homosexuals in isolated midwestern communities.

The breakthrough came in 1994, when the Kaposi sarcoma–associated herpes virus (human herpesvirus type 8 [HHV-8]) was identified using representational difference analysis. HHV-8 has been linked closely with all 4 types of Kaposi sarcoma, ie, classic (traditional), endemic (African), epidemic (AIDS related), and iatrogenic (related to immunosuppression). [7] Since then, much research has shown that HHV-8 appears to be necessary to, but not sufficient for, the development of Kaposi sarcoma. [8]

Nevertheless, two critical questions remain. Is Kaposi sarcoma a hyperplasia or a neoplasm? Is it always multicentric or can it be metastatic as well? The authors favor the latter interpretation of both points.

Kaposi sarcoma and its causative agent, Karposi sarcoma–associated herpesvirus, have distinctive largely unexplained geographic distributions. [9] The "oncoweed" hypothesis states that biologic plants in the environment account for the lytic reactivation of human herpesvirus 8. Quinine and its derivatives might better explain the epidemiology of Kaposi sarcoma in Africa than oncoweeds. Thus, an "oncodrug" hypothesis has been proposed, specifically with regard to quinine and its derivatives for African Kaposi sarcoma.

See the image below.

Elderly American man of Armenian origin with chara Elderly American man of Armenian origin with characteristic violaceous plaques of the legs, a good example of classic Kaposi sarcoma.

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