Renal cell carcinoma with non-Hodgkin's lymphoma infiltration: a case report.

The coexistence of renal cell carcinoma and non-Hodgkin's lymphoma is more common than expected in the general population; however, renal cell carcinoma with infiltration by non-Hodgkin's lymphoma has rarely been reported. Here we report on a 77-year-old patient who presented with small lymphocytic lymphoma in the jugulodigastric lymph node. He underwent nephrectomy for a renal mass 5 months later. On histopathological examination, the mass was diagnosed as a grade III renal cell carcinoma with infiltrated small lymphocytic lymphoma that was positive for B-cells (CD20). This case is discussed in terms of the coexistence of these tumors and tumor to tumor metastasis.