Bone Marrow Cancer (Myeloma) in Cats

4 min read

Multiple Myeloma in Cats

Multiple myeloma is an uncommon cancer that is derived from a clonal population of cancerous (malignant) plasma cells in the bone marrow. A “clonal population of cells” is a group of cells that have descended from a single cell; all of them have the same genetic make-up. Plasma cells are specialized white-blood cells, lymphocytes that have been altered to produce immunoglobulin, an immune protein or antibody necessary for fighting disease.

Three of four defining features must be present for a diagnosis of multiple myeloma: immune protein from a single clone of cells (known as a monoclonal gammopathy), seen as a spike in the gamma region of a protein analysis of the blood (known as a protein electrophoresis); cancerous plasma cells or a high number of plasma cells in the bone marrow (known as plasmacytosis); destruction of areas of bone (known as lytic bone lesions); and a particular type of protein found in the urine (known as Bence Jones [light-chain] proteinuria).

Multiple myeloma occurs primarily in middle-aged or older cats (6-13 years).

Symptoms and Types


Attributed to bone infiltration and destruction of bone, effects of proteins produced by the tumor (such as increased protein in the blood leading to sludging of the blood and kidney damage), and infiltration of organ(s) by cancerous cells. Symptoms depend on location and extent of disease.

  • Weakness
  • Lameness
  • Generalized discomfort or uneasiness
  • Pain
  • Fever
  • Partial paralysis
  • Increased thirst
  • Increased urination
  • Urinary incontinence
  • Dementia
  • Labored breathing
  • Lack of appetite
  • Weight loss
  • Bleeding from the nose that may involve one or both nostrils
  • Bleeding in the back part of the eye and blindness
  • Excessive bleeding from needle punctures to collect blood or to administer intravenous medications and/or fluids
  • Bleeding involving the gastrointestinal tract




You will need to give a thorough history of your cat’s health and onset of symptoms. The history you provide may give your veterinarian clues as to which organs are causing secondary symptoms. Along with a thorough physical examination, your veterinarian will also conduct a thorough ophthalmological examination on your cat, if the eyes are showing symptoms of a diseased state.

Symptoms for multiple myeloma resemble those of several other diseases. Your veterinarian will need to rule out a number of other possibilities for the symptoms, such as infections, other types of tumors, and immune-mediated illnesses. To do that, your doctor will conduct a complete blood profile, including a chemical blood profile, a complete blood count, and a urinalysis. Diagnostic imaging will include X-rays of the vertebra and limbs to look for bone lesions, and ultrasound to examine the internal organs.

Related Posts

Bone Marrow Cancer (Myeloma) in Dogs

PetMD Editorial
Apr 04, 2016

Cancer of Plasma Cells in Ferrets

PetMD Editorial
Jun 23, 2010

Abnormal Protein Production in Cats

Victoria Heuer
Aug 18, 2010