Abstract: Strangulating lipomata are the most common cause of small intestinal strangulating obstruction. Evaluation of histological features of pathological and non-pathological lipomata, and the histological properties of omental and retroperitoneal fat have not been described. Objective: To characterise histological features of equine abdominal lipomata, omental and retroperitoneal adipose tissue, and associations between them. Methods: Prospective observational anatomic (gross and histological). Methods: Horses undergoing emergency laparotomy for management of abdominal pain in a single hospital were recruited. Signalment was recorded. Gross features of lipomata that were a cause of strangulating obstruction (pathological lipomata [PAL]), and lipomata that were currently not causing an intestinal obstruction (pedunculated [PEL] or non-pedunculated [NPL]) were recorded. Lipomata that were removed intra-operatively, or following owner-requested euthanasia, as well as omentum or retroperitoneal adipose tissue, where excised routinely as part of routine management (or post-euthanasia) were fixed in 10% neutral-buffered formalin prior to staining (haematoxylin and eosin, picrosirius red). Descriptive statistical analyses were performed. Pearson's chi-square, Fisher's exact or Kruskal-Wallis tests, as appropriate, were used to assess associations. Significance was p < 0.05. Results: Seventy-four horses were enrolled; 71 lipomata, 48 retroperitoneal adipose samples, and 26 omental samples underwent evaluation. Increasing age was predictive of lipomata presence and PAL/PEL. Neither omental nor retroperitoneal adipose tissue histological features were correlated with lipomata presence or type. PAL were more likely to exhibit capsule formation (PAL: 70%, NPL: 42%, p = 0.03), and had a higher vascular density (median 10.6; IQR: 8.8-16.8; p = 0.05), compared with NPL. PEL were more likely to exhibit steatonecrosis (PEL: 92%, NPL: 33%, p = 0.01) and had increased mineralisation (PEL: 67%, NPL: 17%, p = 0.05) compared with NPL. Conclusions: Small sample size. Conclusions: Histological features of omental and retroperitoneal fat do not predict presence of lipomata or type. However, there are histological features of PAL and PEL which may be related to pathological potential.
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This research study explores the histological features of equine abdominal lipomata (fatty growths), omental (belly fat), and retroperitoneal (fat found behind the abdominal area) adipose tissue, to understand its pathogenesis and risk to the horses’ health. The study was carried out on horses that had to undergo emergency surgery due to abdominal pain in a single hospital.
Study Design and Methodology
The study was a prospective observational anatomic study, meaning observations were made in a forward-looking manner based on the anatomy of the involved tissues.
Animals undergoing abdominal surgery at a veterinary hospital due to pain were included in the study.
The team collected information about the horses’ breed, sex, and age.
The researchers recorded the appearance of the lipomata that caused the obstruction (pathological lipomata) and those that didn’t (either pedunculated or non-pedunculated).
Lipomata, omental or retroperitoneal adipose tissues that were removed during surgery or after euthanasia, were preserved in formalin and stained for examination.
Results
The studies involved 74 horses, and scientists evaluated 71 lipomata, 48 retroperitoneal adipose samples, and 26 omental samples.
Older horses were found more likely to have lipomata.
Pathological lipomata were more likely to form a capsule, and they also showed a higher vascular density, compared to non-pedunculated lipomata.
Pedunculated lipomata were more likely to show a certain type of fat tissue death (steatonecrosis), and had increased mineralization compared to non-pedunculated lipomata.
The histological features of omental and retroperitoneal fat tissues did not predict the presence of lipomata or its type.
Conclusions
Despite the small sample size, there were certain characteristics associated with pathological and pedunculated lipomata that may point to an apparent pathological potential.
The findings imply that the examination of equine abdominal lipomata may generate insights with regard to their pathogenesis, therefore, it could help to manage the health of horses better in the future.
Cite This Article
APA
Gillen A, Archer D, Ireland J, Rocchigiani G.
(2025).
Characterising equine abdominal lipomata: Can histological features improve the understanding of pathogenesis and risk?
Equine Vet J.
https://doi.org/10.1111/evj.14483
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