Figure 14b. Leiomyoma of the renal sinus in a 28-year-old woman with gross hematuria. (a) Excretory urogram shows focal smooth mass effect on the pelvicalices of the right kidney (arrows). (b) Axial contrast-enhanced CT scan obtained during the nephrographic phase shows a small mass (arrow) with soft-tissue attenuation obliterating the fat in the right renal sinus along the posterior margin of the renal pelvis. (c) Coronal reformatted CT scan shows the round soft-tissue attenuation mass (arrow) in the right renal sinus and mild dilatation of the pelvicaliceal system. (d) Photograph of the surgical specimen shows the well-defined round mass (arrows) in the renal sinus. Microscopic examination demonstrated a renal leiomyoma.