Diffuse retroperitoneal amyloidosis due to renal cell carcinoma.

The case of a 61-year-old man with haematuria, in whom CT demonstrated a solid renal mass and extensive retroperitoneal infiltration, is presented. This combination of CT findings resulted in significant diagnostic uncertainty. Pathological analysis demonstrated renal cell carcinoma, with secondary amyloidosis in the retroperitoneum. Amyloidosis secondary to renal cell carcinoma has not been previously described as a cause of retroperitoneal infiltration.