Recognizing the Signs of Lymphoma in Dogs
Lymphoma is a cancer that affects lymphocytes—white blood cells crucial for your dog's immune defense. Since lymph tissue exists throughout the body, lymphoma can show up in many forms and locations. Spotting the early signs is key to getting your dog timely care.
Understanding Lymphoma Types and Where They Strike
Lymphoma isn't just one disease; there are over 30 types. The four most common forms each have their own set of symptoms:
- Multicentric lymphoma: The most frequent type (about 80–85% of cases). You'll often notice firm, enlarged, non-painful swellings under the skin. These pop up under the jaw, in front of the shoulders, behind the knees, armpits, or groin. At first, your dog might seem healthy aside from these lumps. As things progress, you could see lethargy, weight loss, poor appetite, vomiting, diarrhea, increased thirst/urination, and weakness.
- Alimentary (gastrointestinal) lymphoma: This form targets the digestive tract. Signs include vomiting, diarrhea, weight loss, belly pain, low appetite, and tiredness. Swollen lymph nodes aren't as common here; it's mostly gut trouble.
- Mediastinal lymphoma: Rare but serious—it hits lymph tissues in the chest. Watch for difficulty breathing, heavy panting or belly breathing, swelling of the face or legs, coughing, thirst/urination spikes (especially if calcium is high), and fatigue. Chest X-rays may reveal masses inside.
- Extranodal lymphoma: This means lymphoma starts outside typical lymph organs—like skin (cutaneous), eyes, kidneys, brain/nerves or bones. For cutaneous types: look for dry/flaky red patches, thickened or ulcerated skin, nodules or mouth lesions. If nerves are involved: seizures may occur.
The Progression: Stages and Substages
Lymphoma's severity depends on how far it's spread:
- Stage I: One lymph node affected.
- Stage II: Several nodes on one side of diaphragm.
- Stage III: Generalized node involvement everywhere.
- Stage IV: Liver/spleen now involved.
- Stage V: Bone marrow/blood/other rare sites (including brain).
Your vet will also note if your dog feels sick (Substage B) or seems well aside from swollen nodes (Substage A). Most dogs get diagnosed at Stage III or IV—usually after owners spot multiple swollen nodes.
The Most Common Warning Signs to Watch For
- Lumps under skin that feel firm but not painful—often under jaw/neck/armpits/groin/knees
- Lethargy—your dog just isn't as energetic as usual
- Loss of appetite—turning away from food or eating less than normal
- Weight loss—even if eating habits haven't changed much
- Vomiting and/or diarrhea—especially with alimentary lymphoma
- Increased thirst and urination—sometimes linked to high calcium levels from cancer activity
If lymphoma affects other organs:
- Coughing or labored breathing (chest involvement)
- Puffy face or swollen legs (mediastinal form)
- Patches of irritated/red/thickened skin or skin sores (cutaneous/extranodal)
- Belly pain (digestive tract involvement)
A Closer Look at Diagnosis and What Comes Next
If you notice any combination of these signs—especially persistent lumps—it’s time to see your veterinarian. Diagnosis usually involves:
- A physical exam to check all lymph nodes and general health.
- Aspirating cells from a lump with a fine needle for microscopic analysis.
- Bigger tissue samples (biopsy) if needed for clarity.
Your vet may also order bloodwork to check organ function and X-rays/ultrasound to see if internal organs are involved. Other specialized tests can help pinpoint exactly what type of lymphoma your dog has—and what treatment might work best.
Treatment Options After Diagnosis
Chemotherapy is usually recommended because lymphoma spreads throughout the body. Most dogs tolerate chemo well—with only mild side effects like temporary tummy upset or slight tiredness. Surgery/radiation are less common but may be used for localized forms like nasal or cutaneous lymphoma. Prednisone can help ease symptoms if chemotherapy isn’t an option but only provides short-term relief.
The Outlook for Dogs With Lymphoma
If left untreated, survival averages four to six weeks after diagnosis. With chemotherapy—especially multi-drug protocols like CHOP—remission rates are high (80–90% for multicentric cases), with average survival times between nine months and a year (sometimes longer). Relapses are common as cancer cells adapt to treatment; second remissions are possible but usually shorter than the first round.
The Takeaway: Early Detection Matters
If you spot new lumps on your dog—or see unexplained changes in energy level/appetite/weight—it’s smart to get things checked out quickly. Lymphoma can progress rapidly but with prompt diagnosis and appropriate treatment many dogs maintain a good quality of life for months or more after diagnosis.
