Figure 6b. Multilocular cystic renal cell carcinoma in a 52-year-old woman. (a) Unenhanced CT scan shows a 3-cm-diameter lobulated heterogeneously hyperattenuating (40 HU) renal mass (arrows). (b) Contrast-enhanced CT scan shows no enhancement of the mass. (c) Contrast-enhanced CT scan at a lower level shows enhancing septa (arrows). (d) Histologic section viewed at low power (original magnification, x 100; hematoxylin-eosin stain) shows several cystic areas separated by septa (arrow). (e) Histologic section viewed at high power (original magnification, x 400; hematoxylin-eosin stain) shows a single layer of renal cell carcinoma cells of the clear cell type (arrow) lining one of the septa.