Background: Incidence and risk factors for skin tumors following renal transplantation can vary geographically; therefore, a retrospective study was performed to determine the incidence of and potential risk factors for skin cancer at 14 Transplant Centers in Iran between 1984 and 2008.
Material/Methods: We enrolled 11,255 kidney transplant recipients who were examined for all skin tumors. All skin cancers were established by histological examination. The data collection included the patient’s age and sex, immunosuppressive regimen before and after diagnosis of tumor, rejection episodes, post-transplant latency period, other concurrent neoplastic problems, renal allograft function and outcome.
Results: One hundred and twenty-eight (1.14%) renal recipients had skin tumor, representing half of all post-transplant malignancies (128 out of 245 cases). Kaposi’s sarcoma was the most common post-transplant cancer compared with other skin tumors. Male recipients had more tumors than did females (P=0.04); the male-to-female ratio in the affected patients was 2.5:1. The age at transplantation of patients with skin tumor was higher compared to RTRs without skin tumor (47±11 vs. 38±15 years, P=0.000), and individuals older than 45 years were at higher risk (odds ratio=3.8, 95%CI 2.6–5.5) of skin cancers. Patients consuming azathioprine were at risk more of skin cancer compared with those were on MMF (odds ratio =2.9, 95%, CI 2.0–4.2). The overall mortality was low (7.8%) in cases with skin cancer.
Conclusions: This study showed that male sex, increased age, prolonged immunosuppression and azathioprine increased the risk of skin tumors after renal transplantation.

Keywords: Kaposi’s sarcoma, cancer, Kidney Transplantation, Immunosuppression