Case of the month: 13 year old Labrador with lethargy and hindlimb weakness
Signalment and anamnesis
- 13 year old Labrador Retriever, male castrated
- Lethargy and hindlimb weakness since a few weeks
For further clarification the following radiographs were taken:
Radiographic description
- The lateral images of the thoracic and lumbar spine show a heterogeneous bone architecture with numerous small, ovoid “punched-out” osteolytic lesions of variable sizes in the region of the vertebra and pelvic bones.
- The changes are most pronounced in the region of the vertebral spinal processes and pelvic bones (os ischium, os ilium).
- There is no evidence of a pathologic fracture at this point in time.
Diagnosis
- Polyostotic aggressive bone lesion;
- Multiple myeloma is the most likely given the distribution and appearance of the osteolytic lesions.
- Other polyostotic aggressive bone tumors such as lymphoma, polyostotic osteosarcoma or bone metastasis are possible differential diagnoses but less likely.
Outcome
- The dog was diagnosed with multiple myeloma by serum protein electrophoresis and is being treated with palliative chemotherapy.
- The dog is doing well at the moment.
Discussion
- Multiple myeloma is the most common polyostotic primary bone tumor.
- The neoplastic proliferation of plasma cells in the bone marrow leads to osteoclastic activity, which results in bone resorption.
- Focal “punched-out” osteolytic lesions in the vertebrae, ribs and long bones are typical for multiple myeloma.
Many thanks to Dr. ECVDI Thorsten Rick for this case report!
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