2004 Radiology Exam - Abdomen Case 2

Objective of the Case

To recognize the presence of prostatomegaly, sublumbar lymph node enlargement and adjacent productive reaction associated with ventral margins of the caudal lumbar vertebrae. A secondary expectation was to recognize a distal femoral destructive lesion. Cogently explaining all radiographic findings with a single, unifying diagnosis was an important component of this exam case.

Information Provided to Candidate

Seven-year-old male Beagle presented with a recent history of straining to urinate or defecate. See images below. Click to enlarge.

Findings Expected from Candidate

The candidates were expected to recognize the presence prostatomegaly, urinary bladder distension and cranial displacement, a mineralized sublumbar soft tissue mass that extends caudally into the pelvic cavity, productive reaction involving the ventral margins of the caudal lumbar vertebrae and ventral displacement and narrowing of the descending colon. A secondary expectation was identification of a destructive bone lesion and reactive periosteal production involving the distal metaphysis/diaphysis of one femur.

Conclusion Expected from the Candidate

The most likely conclusion is a diagnosis of malignant prostatic neoplasia with regional metastasis to sublumbar lymph nodes and the lumbar spine and distant metastasis to the distal metaphysis of one femur. Primary neoplasia arising from the urinary bladder, urethra, descending colon/rectum or anal sacs could also be included in a differential diagnosis.