A 57-year-old female came to emergency room with sudden onset of left flank pain, and in shock. The patient was an acutely-ill appearing woman with a blood pressure of 80/65 mmHg. Laboratory test showed hemoglobin of 9.5 gm/dl. An immediate computerized tomography (CT) detected a mass in the middle portion of the left kidney, with a density value like fat and with a perirenal hematoma formation. With a impression of renal angiomyolipoma of the left kidney with spontaneous rupture, a nephrectomy was performed. The differential diagnosis is discussed and the literature, reviewed.