Multiple unrelated malignancies following renal transplantation: an evaluation of four cases.

The risk of de novo malignancy is significantly higher in patients who have undergone organ transplantation than in the general population. Long-term immunosuppressive treatment, in addition to age, genetic predisposition and infectious agents, plays a major role in the development of malignancy. Although skin and hemopoietic system cancers are common, atypical presentations of malignancies may occasionally be seen during long-term follow-up in patients with functioning allografts. In this report, four cases, each with more than one different primary malignancy (one patient with three malignancies and three patients with two malignancies), are presented.