[Renal angiomyolipoma. Diagnostic value of magnetic resonance imaging].

Owing to the wider use of ultrasonography, renal angiomyolipoma is now diagnosed with increasing frequency. Within a few months, 10 female patients were explored by ultrasounds, computerized tomography and nuclear magnetic resonance (Magniscan 5,000, 0.5 Tesla). At ultrasonography the lesion was hyperechogenic in 9 cases and heterogenic in 1 case. At computerized tomography 7 patients had a strongly hypodense lesion and 3 had a lesion of slightly positive density. At magnetic resonance imaging the lesion produced a characteristically loud signal similar to that of fatty tissues. In practice, ultrasonography and computerized tomography combined provide the diagnosis in most cases. In case of doubt, especially since the tumour may be small and asymptomatic and the lesions multiple and/or bilateral, magnetic resonance imaging with its fat-like loud signal confirms the diagnosis and leads to partial resection. When no complications are present, it may even suggest that surgery is unnecessary.