🐱 Veterinary Overview of Myeloma-Related Disorders in Cats: Diagnosis and Treatment in 2025 🧬

By Dr. Duncan Houston, BVSc

🔍 What Are Myeloma-Related Disorders?

Myeloma-related disorders are rare cancers in cats that originate from plasma cells—a type of white blood cell responsible for producing antibodies. When these plasma cells become malignant, they are referred to as myeloma cells. The resulting cancers affect multiple organ systems, presenting with diverse symptoms that can complicate diagnosis and treatment.

📋 Types of Myeloma-Related Disorders in Cats

• Myeloma (multiple myeloma)
• Cutaneous extramedullary plasmacytoma (CEMP)
• Non-cutaneous extramedullary plasmacytoma (NCEMP)
• Solitary plasmacytoma of bone (SPB)
• Waldenström’s macroglobulinemia (WM)
• Immunoglobulin-secreting lymphoma
• Myeloma cell leukemia

🧠 Historical Context

Although myeloma was described in humans in the 1800s, feline cases weren’t documented until 1957. Today, while still rare, myeloma-related conditions are better understood but remain complex to treat.

⚠️ Clinical Signs in Cats

Symptoms vary by tumor type and location. Common signs include:

• 🩸 Anemia (causing lethargy, weakness)
• 🧪 Kidney dysfunction (due to paraprotein filtering)
• 💉 Hyperviscosity syndrome (causing blindness, heart issues, and neurological signs)
• 🔬 Tumors in liver, spleen, skin, or bone
• 🦴 Bone pain or fractures from osteolysis
• 🧫 Immunosuppression leading to infection susceptibility

🧬 Pathophysiology: What’s Happening in the Body?

Myeloma cells produce abnormal immunoglobulins called M-proteins or paraproteins. These accumulate in the blood, increasing its viscosity. This thickened blood can damage organs and interfere with clotting. Tumor cells may infiltrate organs, damaging their function, and in some cases, attack bone marrow or bone tissue.

🔬 Diagnosis of Myeloma in Cats

A thorough diagnostic workup is essential. This may include:

• 🩺 Complete blood count (CBC) and serum biochemistry
• 🔍 Serum protein electrophoresis (to detect M-protein)
• 🧫 Bone marrow biopsy
• 🧪 Urinalysis (to assess kidney involvement)
• 🩻 Radiographs and ultrasound (to check for bone or organ involvement)

Diagnosis may take several days and is best handled at a specialist veterinary center.

💊 Treatment Strategies (2025)

Goals of treatment are to reduce tumor burden, relieve symptoms, and improve quality of life. While a cure is unlikely, remission is achievable. Treatment options include:

• Combination Chemotherapy: Most effective. Includes melphalan or cyclophosphamide with prednisolone.
• Supportive Therapy: IV fluids, nutritional support, and antibiotics for secondary infections.

🕒 Median survival time: Approximately 12 months with combination therapy. Resistance to chemotherapy is common over time.

📈 Prognosis and Follow-Up

While complete remission may be possible, most cases relapse. Monitoring includes:

• 📊 Regular bloodwork
• 🧪 Monitoring protein levels
• 🩻 Imaging to track tumor or bone lesions

Some cats may live more than a year with treatment, enjoying good quality of life. However, recurrence is expected, and treatment adjustments will likely be needed over time.

📱 What to Do If You Suspect Myeloma?

Early referral to an oncologist or internal medicine specialist is ideal. For support and consultations, visit AskAVet.com or use the Ask A Vet app to get answers from licensed veterinarians. 🐾

📝 Summary for 2025

• 🧬 Myeloma is a rare but serious plasma cell cancer in cats
• 🧪 Symptoms are systemic and vary by location and paraprotein levels
• 💊 Chemotherapy can induce remission and improve life quality
• 📅 Median survival ~12 months, with relapse common

With expert care and timely intervention, many cats can enjoy extended periods of comfort and stability despite the diagnosis. 🐱❤️