[Renal angiomyolipoma as a cause of acute retroperitoneal hemorrhage].

Angiomyolipoma is a mesenchymal tumor, usually found in the kidney. The pleomorphic appearance and involvement of regional lymph nodes may simulate malignancy, but angiomyolipomas are classified as benign. Renal angiomyolipomas are found in approximately 40% of tuberous sclerosis patients and are usually small, bilateral and asymptomatic nodules. Spontaneous rupture and retroperitoneal haemorrhage may be experienced with larger tumours. Although findings by ultrasonography and computerized tomography are specific for this lesion, histological examination is necessary for a final diagnosis. Small asymptomatic angiomyolipomas should be followed up with sequential CT scans and be removed by enucleation or partial nephrectomy when they reach a size of more than 4 cm in diameter. If the patient suffers from massive bleeding, it is very difficult to preserve the kidney. We report on a 61-year old women who experienced acute retroperitoneal haemorrhage. She was given ten blood transfusions before she was operated on with en bloc removal of the left kidney, an angiomyolipoma with a diameter of 10 cm and a large haematoma.