Fact-sheet: Renal angiomyolipoma
Updated on 04/21/2016 at 11:35 PM
View all RADEOS cases associated with this fact-sheet
Definition
Benign hamartomatous tumor with 3 components in variable proportions: fat, dysplastic vessels, and smooth muscle.
Most common benign kidney tumor
Clinical features
Incidental finding in 80% of cases.
90% solitary and unilateral.
10% multiple and bilateral: strongly associated with tuberous sclerosis of Bourneville.
Sex ratio M:F = 1:4 (1:1 if associated with tuberous sclerosis of Bourneville).
Complications: hemorrhage and rupture.
No malignant degeneration (except epithelioid variant = rare form).
Ultrasound
Often echogenic lesion but not pathognomonic
- CT systematically (thin sections, without contrast, zoomed)
intratumoral fat: density ≤ -20 HU, no calcification
- MRI (T1 without and with fat saturation, without contrast):
T1 hyperintensity with signal drop on fat-saturated sequences
(No In-Phase/Out-of-Phase sequences, as some renal cancers also show signal drop)
- particular form: AML without macroscopic fat: imaging non-contributory: biopsy required for diagnosis.
Familial form: tuberous
sclerosis of Bourneville
Management
Treatment:
>4 cm = increased hemorrhagic risk:
preventive treatment (endovascular treatment by ultra-selective embolization, percutaneous treatment by radiofrequency/microwave/cryoablation, surgical treatment by partial nephrectomy)