Case report links ANNPE and vertebral T-cell lymphoma in a dog: full analysis
Version 2 — Full analysis
A case report published in the March 2026 issue of the Journal of Small Animal Practice details an unusual dual diagnosis in an 8-year-old dog: acute non-compressive nucleus pulposus extrusion, or ANNPE, occurring at the same time as vertebral T-cell lymphoma. The report comes from North Carolina State University clinicians, who describe a dog presenting with peracute paraparesis and MRI findings consistent with ANNPE, but with additional vertebral body abnormalities at T13 that were ultimately diagnosed as lymphoma on surgical biopsy. (pmc.ncbi.nlm.nih.gov)
That combination matters because ANNPE is typically approached as an acute, non-compressive spinal cord injury linked to sudden extrusion of minimally degenerate nucleus pulposus, often with supportive care rather than surgery. MRI is central to diagnosis, and the expected pattern is a focal intramedullary lesion overlying a narrowed disc space without substantial residual compression. In this case, however, the MRI workup also showed vertebral changes outside the classic ANNPE pattern, which prompted further investigation instead of stopping at the first plausible diagnosis. (pmc.ncbi.nlm.nih.gov)
According to the case report, the vertebral lesion was identified on STIR and post-contrast T1-weighted sequences, then confirmed as T-cell lymphoma after biopsy. The dog received a radiation protocol totaling 40 Gy in five daily fractions to the gross tumor volume, with lower-dose coverage to adjacent clinical target volumes. The authors reported that the dog regained the ability to walk within weeks, supporting their interpretation that ANNPE was the main driver of the acute neurologic deficits, while the vertebral lymphoma was an important concurrent finding with treatment implications of its own. (pmc.ncbi.nlm.nih.gov)
There isn’t much published commentary on this individual case yet, but the broader literature supports the authors’ caution. Vertebral and spinal lymphomas in dogs are uncommon and can be diagnostically slippery. A 2023 Journal of Veterinary Internal Medicine case described large T-cell extradural lymphoma causing progressive tetraparesis and cervical pain, while an older report documented polyostotic vertebral T-cell lymphoma associated with paraparesis and vertebral bone changes. Imaging reviews also note that contrast MRI can be especially useful for identifying infiltrative vertebral or extradural neoplasia that may not be obvious on more limited studies. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For general practitioners, emergency clinicians, neurologists, and radiologists, the practical takeaway is not that ANNPE should suddenly be treated as a neoplastic disease, but that pattern recognition has limits. When a dog presents with a textbook acute myelopathy, it’s easy to anchor on ANNPE or fibrocartilaginous embolism and move on. This report argues for a more disciplined read of the entire study, including vertebral marrow signal, contrast enhancement, and adjacent osseous structures, especially when findings are asymmetric, atypical, or more extensive than expected. (pmc.ncbi.nlm.nih.gov)
It also reinforces the value of MRI protocol design. The authors specifically highlight STIR and post-contrast T1-weighted imaging as important to detecting the vertebral lesion. That’s relevant in referral and specialty settings where abbreviated protocols may be tempting in presumed ANNPE cases, and in primary care discussions with pet parents about why advanced imaging sometimes uncovers more than one process. A concurrent lesion may not explain the acute presentation, but it can still materially change prognosis, staging, referral decisions, and treatment planning. (pmc.ncbi.nlm.nih.gov)
What to watch: Watch for whether future case series clarify how often presumed ANNPE coexists with clinically significant vertebral pathology, and whether this prompts broader use of contrast-enhanced spinal MRI protocols in dogs with acute, non-compressive myelopathies. (pmc.ncbi.nlm.nih.gov)