Peer-reviewed veterinary case report
Occurrence of primary lymphocytic hypophysitis in two horses and presence of scattered T-lymphocytes in the normal equine pituitary gland.
- Journal:
- Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
- Year:
- 2017
- Authors:
- Grau-Roma, Llorenç et al.
- Affiliation:
- School of Veterinary Medicine and Sciences · United Kingdom
- Species:
- horse
Plain-English summary
In a study involving two horses, researchers found a condition called lymphocytic hypophysitis (LH), which is inflammation of the pituitary gland. One of the horses was a 14-year-old Appaloosa gelding that had been diagnosed with a related condition called pituitary pars intermedia dysfunction. During examinations of the pituitary glands from 24 horses, two were found to have moderate LH, while others showed either small amounts of lymphocyte inflammation or none at all. The cause of this inflammation is still unclear, but it may be related to the immune system. Overall, the treatment and outcomes for these cases were not specified, but the findings suggest that some lymphocytes in the pituitary gland might be normal for horses.
Abstract
The postmortem examination of a 14-y-old Appaloosa gelding with clinically diagnosed pituitary pars intermedia dysfunction showed a unique finding of moderate multifocal lymphocytic hypophysitis (LH). The pituitary glands of 24 horses submitted for postmortem examination were examined grossly and examined histologically for the presence of lymphocytes. Of these 23 horses, 1 additional case suffered from moderate LH. The 2 cases with LH tested negative for Equid herpesvirus 1 and 4 by polymerase chain reaction and immunohistochemistry (IHC), and no viral particles were observed by electron microscopy in 1 case examined. The cause of LH remains unknown, but based on the T-lymphocytic nature of the inflammation and the human literature, an immune-mediated origin is hypothesized. In addition, the review of 24 cases revealed that 10 horses had few and small multifocal lymphocytic infiltrates within the pituitary gland; the remaining 12 horses showed no evident lymphocytes when examined by hematoxylin and eosin. IHC for CD3 showed the presence of a small number of individual T-lymphocytes scattered through the gland in all examined horses, which appears therefore to be a normal feature of the pituitary gland in horses.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/27852816/