Kaposi's Sarcoma and Transplantation.

Kaposi's sarcoma is a tumour of multicentric origin, composed of endothelium-lined vascular spaces and spindle-shaped cells. The incidence of Kaposi's sarcoma in transplant recipients is 400--500 times greater than that in the general population, and is rising within the transplant population, currently comprising more than 5% of all de novo neoplasms in this group. The exact pathogenesis is still unknown but DNA sequences from human herpesvirus 8 (HHV-8) are present in the different clinical variants of Kaposi's sarcoma. Risk factors associated with development of these tumours posttransplantation include the geographical origin of the patient, HSV-8 infection before and after transplantation, and the immunosuppressive regimen used, but the importance of each factor remains to be determined. Apart from conventional treatment with surgical excision, radiotherapy or chemotherapy, cessation, reduction or modification of immunosuppressive therapy has been shown to be effective in a significant number of patients. This article reviews recent advances in our understanding of Kaposi's sarcoma after transplantation.