2009 Radiology Exam - Musculoskeletal Case 2

• 10 year old Female Spayed German Shep
• Difficulty rising. Painful on hip manipulation.
• Findings and prioritized differential
• Further Imaging recommendations

The musculoskeletal section of the 2009 certifying examination was presented to the candidates as a PowerPoint presentation using jpeg images optimized to display the lesions of interest.

See images below. Click to enlarge.

Radiographic Findings:

• There is a mass-like spherical area of irregularly marginated periosteal new bone arising from the ventral and lateral surfaces of the right ilial wing and body. The periosteal new bone arising from the right ilium overlays the right sacral wing on the VD views. The transition zone between normal and abnormal bone in the right ilium is indistinct.
• There are periarticular osteophytes and moderate remodeling changes at the margins of the coxofemoral joints bilaterally.
• There is an incidental transitional lumbosacral vertebral segment fused to the sacrum and mild to marked smooth solid new bone production at the ventral margins of several caudal lumbar and the lumbosacral disc spaces, consistent with spondylosis deformans.
• There is new bone consistent with enthesiophyte formation in the area of the right prepubic tendon and on the lateral surface of the left ilial wing in the area of gluteal muscle origin.

Radiographic Diagnosis (Synthesis):

• Right ilial aggressive bone lesion, most likely a primary bone tumor or less likely a metastatic lesion to the bone or granulomatous infectious process, such as fungal infection.
• Incidental moderate chronic coxofemoral DJD secondary to canine hip dysplasia, right prepubic tendon and left gluteal chronic degenerative or post traumatic enthesopathy, transitional lumbosacral vertebral segment and degenerative spinal changes.

Recommendations/Management:

• The candidates were expected to recommend biopsy of the right ilial lesion and thoracic imaging with vd, right and left lateral thoracic radiographs or CT to assess for metastatic disease and further evidence of a granulomatous infectious process.
• The recommendation of a pelvic CT exam to further characterize the ilial mass was also an acceptable recommendation.

Candidate performance:

Most candidates performed well on this case. Some candidates incorrectly concluded there was bone lysis in the left side of the sacrum due to the relative reduced opacity resulting from the overlaying mineral opaque mass on the right vs. the gas containing colon on the left when evaluating the vd view. Some candidates confused the periosteal reaction on the ventral surface of the ilium for spondylosis deformans ventral to the sacrum when