Kaposi’s Sarcoma — Etiology and Pathogenesis

Abstract

First described by the Austro-Hungarian dermatologist Moritz Kaposi just over 100 years ago (Kaposi, 1872), Kaposi s sarcoma (KS) was, until recently, considered a rare, slowly progressive tumor of elderly males. In this ‘classical’ form of KS, lesions are mainly confined to the skin and localized preferentially on the extremities. In the early 1960s it emerged that KS was endemic in central Africa, particularly Zaire, and that four different clinical variants of ‘endemic KS’ could be distinguished (reviewed in Buchbinder and Friedman-Kien, 1991; see also Chapter 18). These are (1) benign disease with few lesions reminiscent of classical KS; (2) aggressive disease mainly localized to extremities with local invasions and destruction; (3) widely disseminated disease with visceral involvement; and (4) a lymphadenopathic form with preferential involvement of lymph nodes and visceral organs but minimal mucocutaneous lesions. In addition, KS occurs in iatrogenically immunosuppressed individuals (‘iatrogenic KS’). However, in developed countries, KS is now most commonly associated with HIV infection, and this variant, termed ‘epidemic KS’, is characterized by widely distributed lesions, visceral as well as lymph node involvement and a rapidly progressive course. These clinical aspects of KS are discussed in more detail in Chapter 18.