[Renal angiomyolipoma. Ultrasonography and computerized tomography findings]

To analyze the US and CT findings and their value in the diagnosis and follow-up of renal angiomyolipoma.

The clinical features, US and CT findings in 17 cases of renal angiomyolipoma were reviewed. Patient mean age was 49.1 years, 15 were asymptomatic and two presented with spontaneous bleeding. Two patients with Bourneville's disease presented bilateral lesions. The presumptive diagnosis was based on the US findings in 15 patients and on the CT findings in 16 patients. The remaining patient was evaluated by MRI. Three patients underwent partial nephrectomy and three other patients required total nephrectomy.

Ultrasound is useful in the diagnosis of renal angiomyolipoma and it is probably the method of choice for follow-up. Two thirds were echogenic, although an echogenic lesion is not necessarily fat or viceversa. It is therefore necessary to perform a CT evaluation to make the diagnosis, especially if the tumor produces symptoms. In this series, detection of fat on CT evaluation was diagnostic of renal angiomyolipoma, although fatty tissue can also be found in other tumors or inflammatory lesions. Occasionally, the densitometric findings may not be conclusive due to the artefact of partial volume. The use of 5 mm slices without contrast and volumetric acquisitions for reconstruction can enhance the spatial resolution. It must also be taken into account that the fat content of a lesion can be scanty and may be undetected or not distinguished from other tumors.