10-year-old spayed female Persian

Pertinent Findings:

• Echogenic fluid surrounding both kidneys with multiple septa
• Mild dilation of both renal pelves with right worse than left
• Mineral in both kidneys
• Kidney size difficult to assess (no measurement provided) but right kidney was slightly larger than the left
• The left kidney had a severely abnormal in shape with flattening of the craniomedial pole
• Both kidneys had hyperechoic cortices with loss of corticomedullary distinction
• Minimal retroperitoneal fluid and hyperechoic retroperitoneal fat.

Interpretation:

• Chronic renal degeneration with dystrophic mineral/calculi
• Bilateral perinephric pseudocyst

Case Management:

• GFR  or blood work to assess renal function
• Drain/sample fluid from around kidneys

Final Comments:

This case was well done by all candidates.  Given the signalment of a Persian cat many candidates wanted to link the perinephric pseudocyst with polycystic kidney disease but these are separate disease entities.  Many candidates discussed lymphoma as differential diagnosis for these findings but given the severity of the fluid accumulation this was not considered an appropriate differential diagnosis.