Figure 11.

A 50-year-old woman presented elevated creatinine and new right ureteral obstruction. She was previously treated for B-cell lymphoma with eight cycles of chemotherapy. CT scans showed abnormal soft tissue density (arrows) in the retroperitoneum around the aortic bifurcation. Residual active disease vs. fibrosis from previously treated lymphoma could not be distinguished. On PET scan there is intense activity (arrows) corresponding to the site of abnormal retroperitoneal soft tissue confirming the presence of residual active disease.