Feline Intestinal Lymphoma

"Feline intestinal lymphoma is typically found in older cats. Symptoms include vomiting, diarrhea, anorexia and weight loss. The clinical signs listed may not appear in cats with this condition. Diagnosis involves taking a tissue sample and treatment involves chemotherapy and/or surgery."

Feline intestinal lymphoma (also known as feline gastrointestinal lymphoma) is the most common form of lymphoma in cats. It is most common in older cats, at least nine years of age. It is slightly more common in males than in females. Domestic short hair breeds have a higher incidence.

Sometimes there is an actual mass that forms in the intestine, and sometimes there is not. In that case, it means that the lymphoma has simply infiltrated the intestine.

Feline Intestinal Lymphoma Symptoms

Symptoms of feline intestinal lymphoma include:

It is possible to have little or no vomiting or diarrhea with weight loss or loss of appetite (anorexia).

Feline Intestinal Lymphoma Diagnosis

Feline intestinal lymphoma is diagnosed with a biopsy (tissue sample). Cells from the intestine must be examined under a microscope. These cells can be obtained in a couple of ways.

The most effective way is through surgery. That way a full-thickness biopsy can be taken, meaning a full-thickness piece of the intestine can be obtained for examination. This will give the best results. In addition, if there is a mass present, it can be removed during the surgery.

Another way to obtain a biopsy from the intestine is through endoscopy. The cat is sedated and instruments are passed down her throat, through her stomach and into her intestine to obtain a sample. This is a less invasive procedure than surgery, but does not allow for a full-thickness sample to be obtained.

If there is a mass in the intestine, cells can be aspirated from the mass with a syringe. This is an alternative to a biopsy. It is usually, but not always effective.

The full-thickness biopsy is the recommended method, however, because intestinal lymphoma can look a lot like inflammatory bowel disease and that may be the only way to distinguish the two.

Ultrasound might also be effective in determining if there have been changes in the thickness of the abdominal wall.

Lymphoma is graded high, intermediate, or low, according to how rapidly the cells are dividing and how malignant they appear, with “high” being the most malignant. It’s not possible to grade lymphoma based on aspirated cells, which is another reason a biopsy is preferred.

Feline Intestinal Lymphoma Treatment

Even if the tumor appears localized, removing the mass will not cure feline intestinal lymphoma. Chemotherapy will be necessary if the cat is going to survive.

Cats tend to tolerate chemotherapy well. They may experience a lack of appetite, vomiting, and fatigue.

The success of chemotherapy varies widely, and depends in part on the grade of the lymphoma. Chemotherapy for high-grade gastrointestinal lymphoma is poor. The clinical response for low-grade lymphoma is good. Some cats diagnosed with feline intestinal lymphoma live only a couple of months from the time of diagnosis even with treatment, while others live a year or more. Specific study results are listed below.

Severe cases may call for surgery. Cats that receive surgery in general to not have a better outcome although this could because only the sickest cats are candidates. Surgery is used if your cat is suffering from some type of partial or complete blockage in the intestines. Even with surgery, chemotherapy is often used a follow up treatment to ensure that the all lymphoma cells are treated.

Feline Intestinal Lymphoma Treatment and Results

High Grade Gastrointestinal Lymphoma Test Results





cyclophosphamide, vincristine, and prednisone (CVP)

Six cats achieved complete remission with a median remission duration of 19 weeks, and a median survival time of 26 weeks


cyclophosphamide, vincristine, and methotrexate

median survival time of 12 weeks

Mooney CVP plus L-asparaginase and methotrexate 62% achieved complete remission for a median survival time of 7 months
Mauldin CVP plus doxorubicin, methotrexate, and L-asparaginase (CHOP-like). 67% in complete remission, with a 21 week disease-free interval. Median survival time was 30 weeks


CVP plus doxorubicin, L-asparaginase, and methotrexate

38% achieved complete remission, 57% partial remission, and 5% had stable or progressive disease. The median disease free interval was 20 weeks, and median survival time 40 weeks. For those achieving a complete remission, the disease free interval was 40 weeks, but median survival was only 41.5 weeks.

Feline Intestinal Lymphoma Treatment and Results

Low Grade Gastrointestinal Test Results





prednisone (10 mg/cat/day) and high-dose pulse chlorambucil (Leukeran; 15 mg/m2 of body surface area, orally, once daily for 4 days, repeated every 3 weeks

69% achieved complete clinical remission, with a median disease-free interval for cats that achieved complete remission of 20.5 months (range, 5.8-49 months). Median survival time for all cats was 17 months (range, 0.33-50 months), with a median survival time of 22.8 months for cats that achieved complete remission (range: 10-50 months). . Reactions to chlorambucil were rare, but included vomiting, diarrhea, anorexia, lethargy, and neutropenia. No cats required hospitalization or discontinuation of therapy.


Inflammatory Bowel Disease and Intestinal Lymphoma in Cats
Todd R. Tamms, DVM

Feline Gastrointestinal Lymphoma:
Mucosal Architecture, Immunophenotype and Molecular Clonality
Peter F. Moore, BVSc, PhD, Dip. ACVP
School of Veterinary Medicine, VM PMI, University of California, Davis, CA

Feline Gastrointestinal Lymphoma
K.P. Richter
Veterinary Specialty Hospital of San Diego, San Diego, CA, USA.


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