[Hemodialysis case in which RCC was identified after disappearance of perirenal hematoma following spontaneous renal rupture treated by transcatheter arterial embolization].

A 55-year-old man who had been undergoing hemodialysis for 9 years visited our institution after the sudden onset of severe left flank pain. He presented with hypotension and was admitted immediately because computed tomography (CT) revealed a massive perirenal hematoma. Renal arteriography showed contrast media leakage at the lower branch of the left renal artery, and spontaneous renal rupture was diagnosed. Five months after the bleeding was stopped by selective transcatheter embolization of the branch of renal artery, CT showed an enhanced mass at the upper pole of left kidney and renal cell carcinoma (RCC) was suspected. Radical nephrectomy was performed, the pathological diagnosis was clear cell carcinoma, and the man has not experienced recurrence within 36 months after the surgery. RCC did not appear to be the cause of the original hemorrhage because there was a small residual hematoma in the middle of the renal parenchyma that was separated from the RCC. In cases of spontaneous renal rupture, re-evaluation by imaging studies is mandatory after disappearance of perirenal hematoma because imaging studies at the time of the rupture sometimes do not reveal the cause of the hemorrhage.