Lymphoma
Lymphoma is one of the most common cancers in dogs and cats, arising from malignant transformation of lymphocytes. It can affect virtually any organ but most commonly involves lymph nodes (multicentric), gastrointestinal tract (alimentary), chest (mediastinal), or skin (cutaneous). It accounts for 7-24% of all canine neoplasms.
Symptoms & Signs
- Dogs (multicentric): painless enlarged lymph nodes, lethargy, weight loss, decreased appetite
- Cats (alimentary): vomiting, diarrhea, weight loss, palpable abdominal mass
- Mediastinal: difficulty breathing, facial swelling
- Cutaneous: skin nodules or plaques
Causes & Risk Factors
Dogs: largely unknown; genetic predisposition in certain breeds (Golden Retriever, Boxer). Cats: historically associated with Feline Leukemia Virus (FeLV), though FeLV-negative lymphoma is now more common. Environmental factors (herbicides, electromagnetic fields) under investigation.
Diagnosis
Fine needle aspirate of enlarged lymph nodes with cytology. Biopsy for histological classification and grading. Staging: blood work, thoracic radiographs, abdominal ultrasound, bone marrow aspirate. Immunophenotyping (B-cell vs T-cell) guides prognosis.
Treatment
Chemotherapy is the mainstay: CHOP-based protocols (cyclophosphamide, doxorubicin, vincristine, prednisone) for dogs. Single-agent protocols for cats. Radiation for localized disease. Rescue protocols for relapse. Prednisone alone for palliative care.
Prevention
No proven prevention. FeLV vaccination in cats reduces virus-associated lymphoma. Avoiding known environmental carcinogens. Regular veterinary examinations for early detection.
Prognosis
Dogs (B-cell multicentric with CHOP): median survival 12-14 months, 20-25% alive at 2 years. T-cell: shorter survival. Cats (alimentary): median 6-9 months with treatment. Without treatment: 4-6 weeks survival.
Affected Breeds (2)
| Breed | Species | Size |
|---|---|---|
| Bengal | Cat | Large |
| Ferret | Small Mammal | Small |