A patient with renal neoplasm was nephrectomized 5 months after successful renal transplantation. The tumor was clearly diagnosed after renal transplantation, although a computed tomography scan before renal transplantation had suggested its presence. The patient had been on hemodialysis for 11 years, with extensive acquired renal cystic disease before renal transplantation. Pathology revealed a renal cell tumor with granular cells and tubulopapillary structure, consistent with papillary renal cell carcinoma. Karyotype analysis revealed that this tumor, which was 1.7 cm in diameter, showed trisomy of chromosomes 5, 16, and 20 and deletion of chromosome Y. This preliminary study suggests that cytogenetic changes of papillary renal cell tumor associated with acquired cystic disease are similar to those in the general population.