Angiomyolipoma
When angiomyolipoma is a rare benign tumor of the kidney, which has a high proportion of fat tissue.
They occur mostly in women between 40 and 60 years of age. In 80 % of cases are asymptomatic angiomyolipomas in both kidneys, which means they do not cause discomfort. In these patients, there is an equal distribution between men and women. The peak age in this population is 30 years of age. In some patients the angiomyolipoma with tuberous sclerosis ( Tuberous Sclerosis ) is associated.
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Pathology
The angiomyolipoma comes from the perivascular epithelioid cells whose growth is probably dependent on hormones controlled. The angiomyolipoma metastasized not, but may in the adipose tissue surrounding the kidney, renal pelvis and grow in 30 % of cases, even in the renal vein. The tumor accounts for 1% of all surgical findings. The angiomyolipoma associated to 20 % with tuberous sclerosis.
Macroscopically it is unbekapselte gray - yellow lesions, which may be round to oval. In some cases, the angiomyolipoma on a multicentric growth. It can occasionally be a lymph node involvement.
Microscopically, mature fat cells and smooth muscle cells are detectable. The muscle cells can have many mitoses, therefore, the tumor can be misinterpreted as sarcoma. In addition, there are atypical blood vessels.
Diagnosis and Therapy
The symptoms are non-specific, occur where appropriate flank pain. Therefore, imaging techniques can give a possible diagnostic information ( see below). A potentially life-threatening complication of Angiomyolipoms is a hemorrhage due to spontaneous rupture into the retroperitoneum ( Wunderlich syndrome). Through a pregnancy, the risk of rupture can be strengthened.
Diagnosis
Imaging techniques:
- Ultrasound can be found by the fat content strongly echogenic lesions in the kidney.
- The presentation of the blood vessels is not helpful for the differential diagnosis, as occur similarly in renal cell carcinoma neovascularization when angiomyolipoma.
- Computed tomography shows a caused by the high fat content hypodense mass in the kidney with -20 to -80 Hounsfield units. This allows differentiation from renal cell carcinoma. The angiomyolipoma calcification do not occur.
- In the MRI says the evidence of a high fat content for an angiomyolipoma and not for renal cell carcinoma.
Therapy
If the angiomyolipoma is larger than 4 cm, with severe symptoms or uncertain behavior tumors a partial removal (resection ) of the kidney should be sought.
The selective embolization represents a possible minimally invasive treatment option dar. can with this technique, however, recurrences develop and it may be a drainage of necrotic tissue may be necessary.