Neuromas at the castration site in geldings.

This is a report of a histological finding of unknown clinical significance. Post-castration pain is certainly a common enough occurrence but usually short lived and when not, and progressive, infection at the site of surgery usually found. Occasionally one hears of a stallion with increased aggression following surgery…I put this here for folks who have horses with unexplained problems after castration that could be attributable to pain at the surgery site.
DrO

Acta Vet Scand. 2019 Sep 24;61(1):43. doi: 10.1186/s13028-019-0479-8.
Neuromas at the castration site in geldings.
Bengtsdotter EA1, Ekman S2, Andersen PH3.

Author information:
1. Department of Biomedicine and Veterinary Public Health, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden.
2. Department of Biomedicine and Veterinary Public Health, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden.
3. Department of Clinical Sciences, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden.
Abstract
BACKGROUND:

Inguinal pain, unexplained hind limb lameness, back pain or behavioural problems in geldings could be attributable to painful neuromas that develop as a consequence of crushing and severing the testicular nerves during castration. The presence of neuroma in this anatomical location has never been reported, hence the knowledge of possible clinical relevance is limited. The aim of this study was to histologically investigate the testicular nerves at the castration site in geldings for the presence of neuromas. Proximal spermatic cord remnants were collected from 20 geldings admitted to routine post mortem examination for various reasons. The time of castration was unknown, but it had not been performed during the last year. Spermatic cord specimens were immersed in 10% formalin, trimmed, dehydrated, embedded in paraffin, sectioned and stained with haematoxylin and eosin (HE) for light microscopy. Identification of nerve tissue was done by immuno-localization of nerve specific enolase (NSE).
RESULTS:

Neuromas were found in 21 spermatic cords from 13 geldings and were bilateral in eight of the horses. The neuromas consisted of areas with small groups of non-neoplastic proliferations of peripheral neural tissue. The tissue included neurofilaments and Schwann cells, intermingled or surrounded with, epineural, perineural and endoneural fibrous tissue. The neural tissue immunostained positive with NSE.
CONCLUSIONS:

This study showed neuromas of the remnant testicular nerves at the site of castration. Further studies are required to establish if these neuromas in the castration site are painful and if certain castration methods promote their formation. Future studies should also investigate the clinical consequence of these neuromas for the individual horse.