Idiopathic muscular hypertrophy of the oesophagus in the horse: a retrospective study of 31 cases

Authors

  • N. A. Benders,

    Corresponding author
    1. Department of Equine Sciences, Medicine Section, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.152, 3508 TD Utrecht, The Netherlands
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  • E. J. B. Veldhuis Kroeze,

    1. Department of Veterinary Pathology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
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  • J. H. Van Der Kolk

    1. Department of Equine Sciences, Medicine Section, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.152, 3508 TD Utrecht, The Netherlands
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  • 2

    Dierenartsencentrum Heerlen, Sittarderweg 79b, 6412 CC Heerlen, The Netherlands.

Department of Equine Sciences, Medicine Section, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.152, 3508 TD Utrecht, The Netherlands

Summary

Reasons for performing study: To present the first report of a case series concerning equine idiopathic muscular hypertrophy of the oesophagus (IMHO).

Objectives: To investigate the clinical and pathological features of the disorder.

Methods: The medical records of 31 horses suffering from the disorder were reviewed retrospectively. In all these animals the diagnosis was confirmed at post mortem examination.

Results: The median age of the affected horses was 12.5 ± 5.6 years (range 1–26) without sex or breed predilection. Only 2 out of 31 horses showed clinical signs associated with oesophageal dysfunction, indicating that the muscular hypertrophy was rather a coincidental post mortem finding. Histology revealed thickening of the distal portion of the oesophagus mainly involving the circular layer of the tunica muscularis without fibrosis or inflammation. In 8 cases, the disorder was seen in concurrence with idiopathic hypertrophy of the tunica muscularis of various other parts of the gastrointestinal tract.

Conclusions: In the majority of patients, IMHO was a coincidental finding at post mortem examination usually confined to the smooth, circular muscle layer of the tunica muscularis externa.

Potential relevance: Further research is necessary to study the precise effect of IMHO on oesophageal function.

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