The use of immunosuppressant's increases the risk of developing malignancies in renal allograft patients. One of the most
important malignancies, Kaposi's sarcoma, can cause mortality and graft failure among renal allograft patients. We report
the case of a 39-year-old male diagnosed with multiple visceral Kaposi's sarcoma 6 months after a second cadaveric renal
allograft. The patient's renal function was markedly deteriorated at admission and required hemodialysis initially. Radiologic
studies revealed Kaposi's sarcoma in multiple lymph nodes, liver, lung, and peritoneum. The excisional biopsy of an inguinal
lymph node confirmed this diagnosis. After diagnosis, tacrolimus treatment was gradually decreased, and sirolimus treatment
initiated. The patient did not receive any chemotherapy or radiotherapy. The Kaposi's sarcoma lesions decreased dramatically
(both in size and number) 1 month after sirolimus treatment, and kidney graft function improved. This case thus shows
successful sirolimus treatment of visceral Kaposi's sarcoma in a renal allograft patient.