Answers to Case 1-3-9
1. Figures 1-3-9a,b are from a nephrostogram study of the left urinary tract, showing
multiple subtle but persistent filling defects in the left upper ureter, just
beyond the pelviureteric junction. These fi lling defects appear to be mucosal in
location, and extend into the lumen from the ureteric wall (note the irregularity
of the mucosal outline). The nephrectomy specimen (Figure1-3-9 ) shows the cut
surface of the kidney and upper ureter demonstrating pyelonephritic scarring and
numerous subepithelial cysts of varying size in the pelvis and ureter with microscopic
features of pyeloureteritis cystica.
2. The differential for these radiographic appearances is wide:
• Pyeloureteritis cystica
• Multifocal TCC
• Adherent thrombus
• Vascular impressions
• Metastases e.g. from prostate, stomach, breast (rare)
• TB
• Schistosomiasis
3. In this case the diagnosis was pyeloureteritis cystica, given the history of chronic
infections. However, malignancy must be excluded by endoscopic evaluation or
cytology as appropriate. Pyeloureteritis cystica is thought to occur due to proliferation
of epithelial cells secondary to chronic obstruction/infection, resulting in
multiple subepithelial cysts measuring 1–4 mm. On IVU/retrograde ureterography/
nephrostogram, this causes multiple well-defi ned fi lling defects and ureteric
scalloping as seen in this example. The cysts slowly resolve over months to years
following treatment of the underlying condition. They are not premalignant and
do not cause obstruction.