Lymphoma Diagnosis in Dogs & Cats
Lymphoma is one of the most common cancers in both dogs and cats. In dogs, multicentric lymphoma (generalized lymph node enlargement) is the most common form. In cats, gastrointestinal lymphoma predominates. Because lymphoma is highly treatable when diagnosed early, rapid and accurate diagnosis is critical.
At Sage Veterinary Imaging, digital cytology provides fast, reliable lymphoma diagnosis from fine-needle aspirates of enlarged lymph nodes or affected organs. Lymphoma has a characteristic cytologic appearance that allows confident diagnosis in most cases — often within 24 hours, enabling treatment to begin days sooner than waiting for surgical biopsy results.
SVI offers advanced digital cytology services at our centers in Round Rock, Texas; Spring, Texas; and Sandy, Utah.
Lymphoma at a Glance
What Is Lymphoma?
Lymphoma arises from lymphocytes — white blood cells that normally play a key role in immune function. When lymphocytes become neoplastic, they proliferate uncontrollably and accumulate in lymph nodes, spleen, liver, bone marrow, and other organs. Lymphoma is classified by anatomic location, cell type (B-cell or T-cell), and grade (low-grade vs. high-grade).
In dogs, multicentric lymphoma (involving multiple peripheral lymph nodes) accounts for approximately 80% of cases. Dogs typically present with painless swelling of multiple lymph nodes. B-cell lymphoma is more common than T-cell lymphoma in dogs and generally carries a better prognosis with chemotherapy.
In cats, gastrointestinal lymphoma is the most common form, often presenting with chronic vomiting, weight loss, and diarrhea. Feline GI lymphoma ranges from low-grade (small cell, indolent, treated with oral medications) to high-grade (large cell, aggressive, treated with multi-agent chemotherapy). Other feline forms include mediastinal, nasal, and renal lymphoma. Accurate classification is critical because treatment and prognosis differ dramatically between subtypes.
Signs & Symptoms of Lymphoma
Signs depend on the form of lymphoma. Multicentric lymphoma in dogs typically presents with visible lymph node enlargement, while GI lymphoma in cats may cause chronic, nonspecific digestive signs.
⚠ Early Diagnosis Improves Outcomes
Lymphoma is one of the most treatable cancers in veterinary medicine, with many dogs achieving remission lasting 12+ months with chemotherapy. However, outcomes are best when treatment begins before the patient becomes significantly ill. If you notice swollen lymph nodes, unexplained weight loss, or chronic digestive issues in your pet, pursue prompt veterinary evaluation.
How Digital Cytology Diagnoses Lymphoma
Fine-needle aspiration of enlarged lymph nodes or affected organs with cytologic evaluation is the standard first-line diagnostic for lymphoma. It is faster, less invasive, and less expensive than surgical biopsy, with high diagnostic accuracy.
What Digital Cytology Reveals
Lymphoma diagnosis — Lymphoma typically presents as a monomorphic (uniform) population of large lymphoid cells on cytology. This pattern is distinct from reactive lymph node hyperplasia (which shows a mixed population) and is diagnostic in the majority of cases.
Cell size classification — Cytology distinguishes large-cell (high-grade) from small-cell (low-grade) lymphoma, which is critical for treatment planning and prognosis. Large-cell lymphoma requires aggressive chemotherapy, while small-cell lymphoma may respond to oral medications.
Immunophenotyping support — While cytology alone cannot determine B-cell vs. T-cell immunophenotype, aspirate material can be submitted for flow cytometry or immunocytochemistry to make this distinction, which affects treatment choice and prognosis.
Staging aspirates — Fine-needle aspirates of the liver, spleen, and other potentially affected organs can be evaluated cytologically to determine the extent of disease (staging), which guides treatment intensity.
Treatment monitoring — Follow-up aspirates during chemotherapy can assess treatment response, detect early relapse, and guide protocol adjustments.
Cytology vs. Biopsy for Lymphoma Diagnosis
Cytology (FNA)
Rapid (24-hr), minimally invasive, highly accurate for lymphoma diagnosis. Enables immediate treatment planning. Provides cell size classification.
Histopathology
Provides architectural detail and definitive subtyping. Required for some GI lymphoma cases (endoscopic biopsy). Takes 5-7 days for results.
Flow Cytometry
Determines B-cell vs. T-cell immunophenotype from aspirate material. Important prognostic information. Complements cytology.
Which Breeds Are Most at Risk?
Breeds at Higher Risk
Golden Retrievers have the highest breed prevalence of lymphoma in dogs. Other commonly affected breeds include Labrador Retrievers, Boxers, German Shepherds, Rottweilers, Bernese Mountain Dogs, and Bulldogs. In cats, there is no strong breed predisposition, but Siamese cats may have higher rates of mediastinal lymphoma. FeLV-positive cats have significantly higher lymphoma risk.
What to Expect with Lymphoma Cytology
Fine-needle aspiration of enlarged lymph nodes is a quick, in-office procedure performed by your veterinarian. A small needle is inserted into the enlarged lymph node to collect cells. The procedure is similar to a blood draw and is well-tolerated by most pets without sedation.
Aspirate slides are submitted to Sage Veterinary Imaging for digital cytology evaluation. Results are typically available within 24 hours. The cytology report includes diagnosis, cell morphology assessment, and recommendations for further staging or testing. If lymphoma is confirmed, your veterinarian can begin treatment planning immediately.
Why Choose Sage for Lymphoma Diagnosis
Submit a Cytology Sample
If your pet has enlarged lymph nodes or suspected lymphoma, ask your veterinarian about fine-needle aspiration and digital cytology through Sage for rapid, accurate diagnosis.
Lymphoma Diagnosis FAQ
Fast Answers Matter
Lymphoma is highly treatable, and earlier diagnosis means better outcomes. Digital cytology provides the rapid answers needed to start your pet on the path to remission.