Post renal transplantation Kaposi's sarcoma: a review of its epidemiology, pathogenesis, diagnosis, clinical aspects, and therapy.

BACKGROUND: Kaposi's sarcoma (KS) is a vascular malignancy primarily involving the skin. This neoplasm occurs commonly in acquired immunodeficiency syndrome (AIDS) and post solid organ transplantation. Human herpesvirus type 8 (HHV-8) has been shown to play a causative role in AIDS-associated KS and in post renal transplantation KS.
METHODS: Based on a MEDLINE search, we present a review of the current information on the epidemiology, pathogenesis, diagnosis and treatment of post-transplantation KS (PT-KS) with an emphasis on renal transplantation. RESULT: The different frequencies of PT-KS in different parts of the world seem to be related to seroprevalence of HHV-8 infection. Following renal transplantation and the administration of immunosuppressive therapy, HHV-8 may reactivate. The renal tubular epithelium is a site for HHV-8 latency. Rates of PT-KS in seropositive recipients and anti-HHV-8 mismatched recipients (donor+/recipient-) are approximately 13% and 4.6%, respectively. Additional risk factors for the development of PT-KS include skin color, country of birth, age at the time of transplantation, and different induction regimens including anti-thymocyte globulin, steroid, or anti-interleukin 2-receptor antagonists. Skin is the major site of involvement. Surprisingly, involvement of the transplanted organ has been reported to be extremely rare. Reduction in immunosuppressive therapy and switching to mammalian targets of rapamycin inhibitors, such as sirolimus, are effective treatments for PT-KS. In patients with no response to reduction in immunosuppressive therapy, systemic chemotherapy with different regimens has been reported to be successful.
CONCLUSION: PT-KS in renal transplant patients is an important problem specifically in southern Europe and the Middle East. In the majority of patients, the diagnosis based on clinical suspicion is always essential. Clinicians should bear in mind that PT-KS may threaten graft function and hence result in rejection complications. Appropriate management increases patient survival.