2005 Radiology Exam - Abdomen Case 2

Objective of the Case
To recognize the presence of a retroperitoneal mass effect and decreased retroperitoneal detail. To provide a reasonable differential diagnosis for these findings. To identify a secondary, unrelated radiographic abnormality (cystic calculi).

Information Provided to Candidate
Nine-year-old male Golden Retriever. One-week duration of acute onset depression and anorexia. Bloody discharge from penis. Survey Radiographs.

See images below. Click to enlarge.

Findings Expected from Candidate
There is loss of retroperitoneal detail and a left sided retroperitoneal mass effect. The descending colon is displaced ventrally and to the right supporting the latter finding. The left kidney is poorly visualized but appears enlarged. Multiple opaque calculi are present in the urinary bladder. Mild prostatomegaly is present.

Conclusions Expected from the Candidate
Candidates should have identified the described findings and provided a complete differential diagnosis for the retroperitoneal mass effect and loss of retroperitoneal detail. This should have included; renal and juxtarenal neoplasia, retroperitoneal hemorrhage, renal/ureteral obstruction and collecting system rupture causing uroretroperitoneum, nephritis, renal or perirenal abscess, perinephric cyst/rupture. The candidate should have recognized the urinary calculi and at least considered the possibility that these may have some relation to the retroperitoneal abnormalities (ureteral obstruction). The finding of mild prostatomegaly was not surprising given that this was a 9-year-old male intact dog but candidates were not penalized for providing a differential diagnosis for this finding.

Diagnosis: Renal abscess

Summary of Overall Candidate Performance
Some candidates failed to recognize the retroperitoneal mass effect and loss of retroperitoneal detail. Of those candidates who did correctly identify and describe the findings, few provided a complete differential diagnosis and even fewer included inflammatory disease, an abscess in this case, as a component of the differential.