Managing acute abdomen is a challenge for physicians in the emergency department. An immediate surgery is sometimes required for the hemorrhagic uropathy of renal angiomyolipoma. We present a case with left flank pain and findings of hematuria and pyuria. Abdominal and pelvic computed tomographic scans showed a 3 x 5-cm, fat-containing tumor at the left lower pole of the kidney and a bleeding and perirenal hematoma in the left perirenal space. An urgent left nephrectomy was lifesaving for the postoperative finding of renal angiomyolipoma. It is important to consider the possibility of the presence of such a tumor when spontaneous retroperitoneal hemorrhage and hypovolemic shock are encountered.