Mixed epithelial and stromal tumour of the kidney: imaging features.

Abstract

To describe the features on ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) of mixed epithelial and stromal tumours of the kidney. Five women with renal mixed epithelial and stromal tumours (mean age 55.6 years, range 49-59) who had preoperative imaging were retrospectively analysed. Three ultrasonograms, five contrast-enhanced CT scans, and one contrast-enhanced MRI examination were available for review. Specific imaging features analysed included lesion size, location, enhancement and cystic composition. The presence of calcification, septation, nodularity and a capsule were also evaluated. All mixed epithelial and stromal tumours appeared as well-marginated, multi-septate cystic masses with a nodular component. All lesions were classified as Bosniak category III (three) or IV (two). The presence of calcification (four) or a capsule (three) was variable. Two tumours invaginated into the renal pelvis with no invasion. Mixed epithelial and stromal tumours of the kidney have a diverse radiographic appearance, indistinguishable from multilocular cystic nephroma and cystic renal cell carcinoma.