[Two cases of renal cell carcinoma arising in the native kidney following renal transplantation--clinical study and review of 26 cases reported in Japan].

Renal transplant recipients have an increased risk of developing malignancies due to long-term immunosuppression. Two cases of renal cell carcinoma arising from the native kidney following renal transplantation are reported. Case 1; A 60-year-old man underwent cadaveric renal transplantation on July 31, 1995. He had resumed hemodialysis because of graft failure on June 5, 2000. He was referred to our hospital with macroscopic hematuria on March, 2002. Computed tomography (CT) demonstrated a right renal mass of about 3.0 cm in diameter with bilateral acquired cystic disease of the kidney (ACDK). The radical nephrectomy was performed. Case 2; A 55-year-old man underwent cadaveric renal transplantation on November 15, 1996. He had resumed hemodialysis because of graft failure on June 5, 1996. A left renal mass measuring 3.0 cm in diameter as well as bilateral ACDK were found by CT on July, 2002. Left radical nephrectomy was performed. The histological diagnosis of both renal tumors was renal cell carcinoma, clear cell type, G2, pT1a. Fifty-six renal transplantations (48 were renal allografts from cadavers, while 8 were from living donors) were performed in our hospital from 1980 to 2002. Two patients (3.6%) developed renal cell carcinoma after transplantations. We also discuss a clinical study and review of 26 cases reported in Japan. Since the incidence of malignant neoplasia is high, CT and ultrasonography should be performed routinely on the patients with renal transplantation.