BILATERAL SOLID MULTIFOCAL INTRARENAL AND PERIRENAL LESIONS - DIFFERENTIATION WITH ULTRASONOGRAPHY, COMPUTED-TOMOGRAPHY AND MAGNETIC-RESONANCE-IMAGING

The differential diagnosis of bilateral solid multifocal intrarenal an d perirenal lesions includes neoplastic, infiltrative, inflammatory, a nd vascular disorders, In a retrospective study 560 solid lesions were examined with cross-sectional imaging modalities (computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI)). Th e results suggest that focal inflammatory disease can often be recogni zed because the lesions are poorly defined and may show a rather chara cteristic peripheral rim enhancement following the administration of i ntravenous contrast. Angiomyolipomas can be accurately diagnosed with CT, MR and US imaging, Because of their unique histomorphology they sh ow fat-equivalent attenuation values at CT, hyperintense signal on T1 and hypointense signal on T2-weighted MR images, and appear homogeneou s and hyperechoic with smooth margins at US, By the radiologic appeara nce alone renal metastases cannot be distinguished from lymphoma or re nal cell carcinoma or adenoma, However, when multiple bilateral solid intrarenal or perirenal lesions are found with synchronous metastatic involvement of other organs or occur in the setting of a known primary tumour, the diagnosis of renal metastases Is very likely. In the abse nce of these additional findings, malignant lymphoma has a higher prob ability, Infiltration of perinephric fat and thickening of the perinep hric fascia may occur in inflammatory disease and lymphoma, CT remains the most suitable imaging technique to screen for these additional pe rirenal and extrarenal findings because of ready availability and rela tively short scanning time as compared to MR imaging.