Lymph Node Assessment with Digital Cytology
Enlarged lymph nodes in dogs and cats can indicate lymphoma, metastatic cancer, infection, or reactive inflammation. Determining the cause is critical because treatment varies dramatically between these conditions. Lymph node cytology via fine-needle aspiration is the fastest, least invasive way to establish a diagnosis.
At Sage Veterinary Imaging (SVI), our digital cytology service provides rapid, expert-level evaluation of lymph node aspirates. Whether nodes are enlarged peripherally or deep within the abdomen (identified on ultrasound), our board-certified pathologists deliver accurate diagnoses that guide your veterinarian’s treatment plan.
SVI offers lymph node cytology services at our centers in Round Rock, Texas; Spring, Texas; and Sandy, Utah.
Common Lymph Node Conditions We Diagnose
Lymph node cytology is one of the most diagnostically rewarding cytologic evaluations because lymph nodes yield cells readily and the major disease categories have distinct cytologic patterns.
Lymphoma
Lymphoma is the most common reason for lymph node cytology in dogs and cats. Multicentric lymphoma presents as painless generalized lymph node enlargement and is readily diagnosed on FNA — cytology shows a monomorphic population of large lymphoid cells replacing normal lymph node architecture. Cytology can also distinguish high-grade from low-grade lymphoma in many cases, which impacts treatment decisions. Digital cytology’s high resolution is ideal for evaluating lymphoid cell size and morphology.
Learn more about lymphoma diagnosis →Metastatic Cancer
When a primary tumor has been diagnosed, evaluating regional lymph nodes for metastasis is a critical staging step. Cytology can identify metastatic carcinoma cells, melanoma cells, mast cells, and other tumor types within lymph nodes. This information determines cancer stage and directly influences treatment recommendations — including whether surgery, chemotherapy, or radiation is most appropriate.
Learn more about lymph node staging →Reactive Lymphadenopathy
Reactive lymphadenopathy — lymph node enlargement due to immune stimulation rather than cancer — is a common cause of enlarged lymph nodes, particularly in young dogs. Cytology shows a mixed population of lymphoid cells at various stages of maturation, plasma cells, and sometimes increased macrophages. Differentiating reactive enlargement from early lymphoma can be challenging and may require additional testing (flow cytometry, PARR), but cytology provides the essential first assessment.
Learn more about reactive lymphadenopathy →Infectious Lymphadenitis
Infectious causes of lymph node enlargement include bacterial, fungal (Blastomyces, Histoplasma, Coccidioides), mycobacterial, and protozoal organisms. Cytology may directly identify organisms within lymph node cells, show characteristic inflammatory patterns (pyogranulomatous inflammation suggests fungal infection), and guide specific antimicrobial therapy. In endemic regions, fungal lymphadenitis is an important differential that cytology can rapidly diagnose.
Learn more about infectious lymphadenitis →Cancer Staging Protocols
Lymph node cytology is a key component of cancer staging protocols. For many tumor types, regional lymph node status determines the cancer stage (e.g., WHO staging for mast cell tumors). Our radiologists can identify and sample internal lymph nodes (mesenteric, sublumbar, hepatic, splenic) using ultrasound guidance, providing comprehensive staging information that may not be available through peripheral node sampling alone.
Learn more about cancer staging →Breeds Commonly Affected
Lymph node conditions have notable breed associations. Golden Retrievers, Boxers, and Rottweilers have elevated rates of lymphoma. Labrador Retrievers and Bernese Mountain Dogs are also predisposed. Any breed can develop metastatic lymph node disease depending on the primary tumor type. Dogs in regions endemic for Blastomyces, Histoplasma, or Coccidioides are at risk for fungal lymphadenitis regardless of breed.
How Digital Cytology Helps
Lymph node cytology is highly diagnostic because lymph nodes yield cells abundantly on FNA. Digital whole-slide scanning captures every cell on the slide at high resolution, allowing our pathologists to systematically evaluate cell populations, identify abnormal cells, and compare findings with established diagnostic criteria. The digital format also enables rapid second opinions and consultation when challenging cases arise.
For internal lymph nodes not accessible by palpation, our radiologists perform ultrasound-guided FNA to sample deep abdominal and thoracic nodes. This combined imaging-cytology approach provides staging information that was previously available only through surgery.
What to Expect During Your Visit
Peripheral lymph node FNA is quick and minimally invasive, often performed in your veterinarian’s office or during an imaging visit. For internal lymph nodes, ultrasound-guided sampling is performed at SVI. Slides are prepared, stained, digitized, and reviewed by our pathologist.
Results are typically available within 24–48 hours. For suspected lymphoma where treatment decisions are urgent, same-day preliminary reads can often be provided. If flow cytometry or PARR testing is recommended, those results take an additional 3–5 days.
View all conditions we diagnose →Why Choose Sage Veterinary Imaging
Get Answers for Your Pet
If your pet has enlarged lymph nodes — whether found during a routine exam, as part of cancer staging, or alongside other symptoms — cytologic evaluation is the essential first step toward an accurate diagnosis.
Schedule a Lymph Node Evaluation
Visit one of our three locations to learn more about lymph node cytology and cancer staging services.
Lymph Node Cytology FAQ
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Ready to Get Answers?
Lymph node cytology can identify the cause of your pet’s enlarged lymph nodes and guide the most effective treatment plan. Visit one of our locations to get started.