Kaposi sarcoma (KS) was first described in 1872 by the Hungarian dermatologist, Moritz Kaposi. From that time until the current human immunodeficiency virus (HIV) disease epidemic identified with the Acquired Immunodeficiency Syndrome (AIDS), KS remained a rare tumor. While most of the cases seen in Europe and North America have occurred in elderly men of Italian or Eastern European Jewish ancestry, the neoplasm also occurs in several other distinct populations: young black African adult males, prepubescent children, renal allograft recipients, and other patients receiving immunosuppressive therapy. The disseminated, fulminant form of KS associated with HIV disease is referred to as epidemic KS to distinguish it from the classic, African, and transplant-related varieties of the neoplasm. In addition, KS has been identified in homosexual men apart from the HIV disease epidemic.
Although the histopathology of the different types of the Kaposi tumor is essentially identical in all of these groups, the clinical manifestations and course of the disease differ dramatically. A key piece to the puzzle of KS pathogenesis was the 1994 discovery of a gamma herpes virus, human herpes virus type 8 (HHV-8), also known as Kaposi sarcoma herpes virus. HHV-8 was identified in KS tissue biopsies from virtually all patients with classic, African, transplant-related, and AIDS-associated KS but was absent from noninvolved tissue.[4,5,6,7]
The National Cancer Institute (NCI) provides the PDQ pediatric cancer treatment information summaries as a public service to increase the availability of evidence-based cancer information to health professionals, patients, and the public.
The histiocytic diseases in children and adults include three major classes of disorders of which only one, Langerhans cell histiocytosis (LCH), a dendritic cell disorder, will be discussed. Erdheim-Chester disease (primarily found in adults) and juvenile xanthogranuloma...
Considered a rare disease, classic KS occurs more often in males, with a ratio of approximately 10 to 15 males to 1 female. In North Americans and Europeans, the usual age at onset is between 50 and 70 years. Classic KS tumors usually present with one or more asymptomatic red, purple, or brown patches, plaques, or nodular skin lesions. The disease is often limited to single or multiple lesions usually localized to one or both lower extremities, especially involving the ankles and soles.
Classic KS most commonly runs a relatively benign, indolent course for 10 to 15 years or more, with slow enlargement of the original tumors and the gradual development of additional lesions. Venous stasis and lymphedema of the involved lower extremity are frequent complications. In long-standing cases, systemic lesions can develop along the gastrointestinal tract, in lymph nodes, and in other organs. The visceral lesions are generally asymptomatic and are most often discovered only at autopsy, though clinically, gastrointestinal bleeding can occur. As many as 33% of the patients with classic KS develop a second primary malignancy, which is most often non-Hodgkin lymphoma.[8,9,10]
African Kaposi Sarcoma
In the 1950s, KS was recognized as a relatively common neoplasm endemic in native populations in equatorial Africa and comprised approximately 9% of all cancers seen in Ugandan males. African KS is seen as either an indolent neoplasm identical to the classic disease seen in Europe and North America or as an aggressive disease with fungating and exophytic tumors that may invade the subcutaneous and surrounding tissue including the underlying bone. In Africa, both the indolent and locally more aggressive forms of KS occur with a male-to-female ratio comparable to that observed with the classic KS tumor seen in North America and Europe. In general, however, patients in Africa are significantly younger than their European counterparts. A lymphadenopathic form of KS is also seen in Africa, primarily in prepubescent children (male:female ratio 3:1). In these cases, the generalized lymphadenopathy is frequently associated with visceral organ involvement. The prognosis is very poor with a 100% fatality rate within 3 years.[11,12]