Figure 15a. Leiomyosarcoma of the renal sinus in a 65-year-old woman with left flank pain and a palpable left abdominal mass. (a) Axial contrast-enhanced CT scan shows a large mass (arrows) with heterogeneous attenuation expanding the left renal sinus. The renal parenchyma (P) is markedly compressed and displaced laterally. (b) Coronal turbo spin-echo T2-weighted MR image (6,500/120) shows the location and extent of the tumor (arrows). P = renal parenchyma. (c) Photograph of the surgical specimen shows the relatively well-defined tumor (arrows) (13 x 9 x 8 cm) in the renal sinus. The tumor has a solid and compact cut surface with central hemorrhage and necrosis. It is confined to the sinus and does not invade the renal parenchyma (P) or pelvis. The adjacent renal parenchyma is compressed by the tumor.