Perinephric hemorrhage from metastatic carcinoma to the kidney.

Retroperitoneal hemorrhage caused by a renal tumor is usually due to a renal cell carcinoma or angiomyolipoma. The authors report a case of computed tomographic (CT) demonstration of renal metastases from choriocarcinoma with an associated perinephric hemorrhage. The CT features indicated the acute nature of the hematoma and its confinement within the extracapsular compartment of the perirenal space.