Computed tomographic findings in dogs with multiple myeloma

Area of Science:

• Veterinary Radiology
• Canine Oncology
• Diagnostic Imaging

Background:

• Computed tomography (CT) is the primary imaging tool for diagnosing multiple myeloma (MM) in humans.
• Updated diagnostic criteria for human MM necessitate a re-evaluation of imaging features in veterinary patients.
• Understanding CT characteristics of canine MM is crucial for accurate diagnosis and staging.

Purpose of the Study:

• To establish baseline CT features and lesion distribution in dogs with MM.
• To document changes in osseous lesions following treatment initiation in a subset of dogs.

Main Methods:

• Retrospective, single-center case series including 13 dogs meeting updated MM criteria.
• Staging CT scans performed at diagnosis and prior to treatment initiation.
• Serial imaging used to assess lesion changes post-treatment.

Main Results:

• All dogs exhibited axial skeleton involvement; 69% also had appendicular skeleton involvement.
• Common lesions included large (≥1 cm), lytic, 'punched out' or expansile lesions, primarily in the vertebral column.
• Intramedullary lesions were noted in 61% of dogs, with bilateral humeri/femur involvement in 44% of cases.
• Serial imaging revealed progressive replacement of contrast-enhancing lesions with fat-attenuating tissue, correlating with clinical improvement.

Conclusions:

• This study provides essential baseline CT imaging data for canine multiple myeloma.
• The findings aid in the diagnosis, staging, and monitoring of MM in dogs based on updated criteria.