This malignant tumour of proliferating capillaries and lymphatics may be multifocal. There are two types: the classical, and that associated with immuno-suppression. Human herpesvirus type 8 (HHV8) has been isolated from, and linked to, both types.
Classical Kaposi’s sarcoma is seen most often inAfricans and in elderly Jews of European origin. The tumours are usually on the feet and ankles but may be seen on the hands and on cold parts of the skin (e.g. the ears and nose). Initially they are dark blue to purple macules progressing to tumours and plaques which ulcerate and fungate. The rate of spread is variable but often slow. Tumours may metastasize to lymph nodes and spread to internal organs; oedema of the legs may be severe.
These tumours are very sensitive to radiotherapy which is the treatment of choice during the early stages; chemotherapy, with chlorambucil or vinblas-tine, helps when there is systemic involvement. Life expectancy is 5–9 years.
Kaposi’s sarcoma and immunosuppression (seeFigs 14.32–14.34). Smaller and more subtle (e.g. bruise-like) lesions may occur in an immunodeficient host. This tumour has recently become well known because of its association with AIDS caused by the human immunodeficiency virus (HIV-1). Lesions of AIDS-related Kaposi’s sarcoma can appear anywhere but are most common on the upper trunk and head and neck. The initial bruise-like lesions tend to fol-low tension lines; they become raised, increasingly pigmented and evolve into nodules and plaques. Lesions frequently arise on the oral mucous mem-branes. Interestingly, HIV-positive intravenous drug abusers do not develop Kaposi’s sarcoma as often as do HIV-positive homosexuals. The prognosis of AIDS patients with Kaposi’s sarcoma is poor as most will develop opportunistic infections and the life expect-ancy in this situation is around 1 year. Single lesions respond to radiotherapy, cryotherapy or intralesional vinblastine; systemic treatment with α-interferon has helped some with multiple lesions.