Transitional cell carcinoma of renal allograft associated with BK virus infection

BK virus (BKV) has oncogenic properties and has been associated with different malignancies. However, reports of malignancy in renal transplant recipients are scarce and circumstantial. We report on a renal transplant recipient with a diagnosis of BKV nephropathy for several years, who subsequently developed a renal allograft mass. Renal allograft mass biopsy revealed a high-grade transitional cell carcinoma. The patient underwent a renal allograft nephrectomy and returned to hemodialysis. Neoplastic tissue was positive for BKV DNA by polymerase chain reaction (PCR) and large T-antigen (TAg) by immunohistochemical staining. In contrast, BKV DNA by PCR was negative in non-neoplastic tissue. The presence of BKV DNA and TAg exclusively in the neoplastic tissue, suggest that malignancy was induced by BKV. Of note, JC virus DNA by PCR was negative in the neoplastic tissue. BKV is associated with transitional cell carcinoma of the allograft renal pelvis and that warrants monitoring these patients for this possibility.