[Benign hemorrhagic renal cyst: a case report].

A case of benign hemorrhagic renal cyst in a 64-year-old man is reported. The patient was admitted to our hospital for further evaluation of left upper abdominal mass. CT scan and ultrasonic sonography showed a left giant renal cystic mass. The characteristic findings were thick and irregular wall and heterogeneous contents of the cystic mass. Selective renal arteriography showed a hypervascular area in a part of the cyst wall and hemorrhagic cyst was suspected by MR imaging. The presence of a malignant tumor in the cyst wall was suspected, and radical nephrectomy was performed. The specimen measured 18 x 12 x 8 cm and weighed 1,170 g. The cyst contained bloody fluid and a hemorrhagic degenerating mass. Pathohistological examination showed no evidence of malignant tumor at any site of the cyst wall.