PRL and lymphoma: The following are the current criteria for a diagnosis of PRL [12]: (1) pathologically confirmed renal lymphoma infiltration; (2) no evidence of extrarenal lymphoma involvement of the lymph nodes or internal organs, except for the kidneys and retroperitoneal lymph nodes; (3) the absence of blood counts indicative of leukaemia or manifestations of myelosuppression; and (4) no occurrence of lymphoma at other sites within at least three months of the discovery of renal lymphoma.