Proceedings 31st Symposium ESVN-ECVN

In four dogs with progressive neurological signs, intracranial or spinal MRI‐alterations and severe lymphocytic pleocytosis, PARR was used to detect clonality in native CSF samples. In dog 1 (CSF: 14000 cells/3μl, 60% lymphocytes), PARR of CSF revealed monoclonal B‐cell proliferation. Cytology of a concurrent perianal mass indicated an extraneural component of lymphoma. The dog was euthanized four weeks after diagnosis of stage V lymphoma. In dog 2, CSF pleocytosis (2530 cells/3μl, 100% lymphocytes) with biclonal T‐cell proliferation and an extramedullary lumbar spinal mass indicated T‐cell lymphoma. After 7 months with palliative therapy, the dog was euthanized due to neurological deterioration. Dog 3 was diagnosed with meningoencephalomyelitis of unknown origin after detection of multifocal lesions in MRI affecting brain and spinal cord and pleocytosis (6300 cells/3μl, 87% lymphocytes) in CSF. PARR revealed polyclonal B‐ and T‐cell populations. The dog improved under immunosuppression (prednisolone, cyclosporine) and is stable 6 months after diagnosis. In dog 4, diagnosis was idiopathic pachymeningitis. In CSF, pleocytosis (85 cells/3μl, 86% lymphocytes) and polyclonal T‐cell population in PARR occurred. Oral prednisolone was administered for 7 months. The dog is clinically normal apart from unilateral central blindness 15 months after diagnosis.