Necrotizing pyogranulomatous encephalitis in a cat
Whats your diagnosis #4
Click here for original post
History: An 8 month old castrated male DSH cat with weak PLR’s, slow menace, circling to the left, and then progressed to ataxia, and he had a distendedbladder.
Gross findings: No gross abnormalities
There are many large cells with small dark nuclear fragments
We interpreted the above photo to represent an apoptotic giant cell. Below, a paper from Vet Path (Vet. Pathol. 33:699-703 (1996)) describes a cat infected with FIV having cells with large hyperchromatic nuclei or bizarre multinucleated cells. The similarity to the above photo made us think that FIV was a possibility in this case.
We sent a piece of the brain for an array of PCR tests that included FIV, FeLV, Influenza, Calicivirus, Coronavirus, and many others. The only encephalitic virus not accounted for was Borna virus, which is unlikely but still a possibility. The lesion is very atypical for viral infections, but we wanted to rule out FeLV and FIV infections, since there have been reports of granulomatous encephalitis with HIV in humans and FIV infected cats (Vet Pathol. 1996 Nov;33(6):699-703). When the PCR test results came back we were cautioned that there is a chance of false negatives for the FeLV and FIV results since the specimen didn’t arrive frozen. There is still the possibility of FeLV anfd FIV infection in this cat. FIP can cause similar lesions in cats, but I have not seen them with so many multinucleated cells, and our IHC works very well. Of course other possibilities include an idiopathic or immune mediated condition similar to canine Granulomatous Meningoencephalitis, but we are not prepared to make that diagnosis in this case.
So, we do not have a confirmed diagnosis in this case. If anyone has any other ideas please post a comment.
Encephalitis in cats:
of Italian Cats in Feline Spongiform Encephalopathy Surveillance.
A Retrospective Study of 286 Cases of Neurological Disorders of the Cat. Journal of Comparative Pathology Volume 131, Issues 2-3 pp 112-120; 2004– 47/92 cats had feline infectious peritonitis (FIP) virus. Of the 45 remaining cases (i.e., non-FIP cats) eight had protozoal tissue cysts (presumed but not confirmed to represent toxoplasmosis; and one had cryptococcosis, One cat with FIP also had toxocara infection.
Feline leukemia virus in a captive bobcat. Journal of Wildlife Diseases, 37(1), 2001, pp. 194-200. Multifocal non-suppurative encephalitis, diffuse interstitial pneumonia, multifocal hepatocellular necrosis, non-suppurative peritonitis, and lymphoid depletion.