Multiple myeloma in 16 cats: a retrospective study

Area of Science:

• Veterinary Medicine
• Oncology
• Hematology

Background:

• Limited published data exists on feline multiple myeloma.
• Current diagnostic criteria are extrapolated from canine studies and lack specific feline validation.

Purpose of the Study:

• To evaluate clinical and laboratory findings in cats diagnosed with multiple myeloma.
• To appraise and potentially modify existing diagnostic criteria for feline multiple myeloma.

Main Methods:

• Retrospective analysis of medical records for cats diagnosed with multiple myeloma.
• Inclusion criteria involved meeting at least two of four diagnostic parameters: bone marrow plasmacytosis, paraproteinemia, osteolysis, or light chain proteinuria.
• Postmortem diagnosis was accepted based on multiple plasma cell neoplasms with bone marrow involvement.

Main Results:

• Sixteen cats were diagnosed, with a median age of 14 years. Common findings included hyperglobulinemia (87.5%), hypocholesterolemia (68.7%), anemia (68.7%), and bone lesions (50%).
• Atypical or immature plasma cells were observed in 83.3% of cases. Extramedullary tumors were present in 100% of assessed cats, affecting organs like the spleen, liver, and lymph nodes.
• One case progressed to plasmacytic leukemia.

Conclusions:

• Feline multiple myeloma frequently presents with atypical plasma cell morphology, hypocholesterolemia, anemia, bone lesions, and multi-organ involvement.
• The study advocates for revising diagnostic criteria to incorporate plasma cell morphology and visceral organ infiltration in cats.