Lymphoma in Cats

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Cancer of the Lymphocytes in Cats


Lymphoma is a type of cancer that originates in the lymphocyte cells. A type of white blood cell, lymphocytes play an important and integral role in the body’s defenses in the immune system.

There are two forms of lymphocytes: B and T cells. Lymphoma may involve neoplastic proliferation of T or B, or non-B/non-T type lymphocytes, occurring primarily in the bone marrow, lymph nodes, and visceral organs.

Lymphoma is found to be responsible for around 90 percent of blood cancers and account for about 33 percent of all tumors in cats. Moreover, it is the most common cause of hypercalcemia in cats.

Symptoms and Types

Symptoms are highly variable and depend upon the anatomical form of this tumor. Following are some forms of lymphoma along with the related symptoms in cats:

Mediastinal form (occurs in the space between the pleural sacs/lungs)

Alimentary form(occurs in the gastrointestinal tract, abdomen, liver)

  • Anorexia
  • Lethargy
  • Vomiting
  • Constipation
  • Diarrhea
  • Black or tarry stool
  • Fresh blood in stool

Multicentric form


occurs in the lymph nodes)

  • Swollen lymph nodes (i.e., jaw, under arms, groin)
  • Loss of appetite
  • Weight loss
  • Depression

Solitary form(can occur in any location


  • Symptoms depend upon location

Renal Form(occurs in the kidneys)


The incidence of lymphoma is believed to be associated with exposure to feline leukemia virus (FeLV) and the feline immunodeficiency virus (FIV). Cats that have been infected with either of these viruses have a significantly higher rate of lymphomas than the general cat population.


You will need to give your veterinarian a thorough history of your cat’s health and onset of symptoms. The history and details you provide may give your veterinarian clues as to which organs are being primarily affected. Knowing a starting point can make diagnosis that much easier to pinpoint. Once the initial history has been taken, your veterinarian will perform a complete physical examination on your cat. Routine laboratory testing includes a complete blood count, biochemistry profile, and urinalysis.

The blood test results may show anemia, or the presence of an abnormally high number of lymphoblasts in the peripheral blood, a condition called lymphoblastosis. Lymphoblasts are immature cells which differentiate to form mature lymphocytes; they are normally present in the bone marrow, but if they proliferate uncontrollably they may  migrate to the peripheral blood, resulting in the abnormal condition called lymphoblastosis.

Biochemistry profiling may show an abnormally high creatinine, serum urea nitrogen, liver enzymes, and calcium levels. The urinalysis may reveal abnormally high levels of pigment bilirubin and proteins in the urine. Affected cats are also tested for the feline leukemia virus (FeLV), which is frequently associated with lymphomas. Your veterinarian will also use diagnostic imaging to locate the tumor(s), conducting X-rays of various body regions, especially the region that appears to be affected. A biopsy of the bone marrow will help in confirming the diagnosis conclusively.


A medical condition involving excessive thirst


A term for a type of neoplasm that is made up of lymphoid tissue; these masses are usually malignant in nature


Excessive urination


An in-depth examination of the properties of urine; used to determine the presence or absence of illness


Anything pertaining to an organ


A type of leukocyte in the body


The product of protein being metabolized; can be found in blood or urine.

lymph nodes

Small structures that filter out the lymph and store lymphocytes


The process of removing tissue to examine it, usually for medical reasons.


A certain pigment that is produced when hemoglobin is destroyed.


The digestive tract containing the stomach and intestine


The area between the abdomen and thighs; the inguinal area


An increase in the number of bad white blood cells


A condition of the blood in which normal red blood cell counts or hemoglobin are lacking.

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