Peer-reviewed veterinary case report
What is the "train track" in the retained equine testis?
- Journal:
- Journal of equine veterinary science
- Year:
- 2025
- Authors:
- Giorgio, S Di et al.
- Affiliation:
- Department of Veterinary Sciences · Italy
- Species:
- horse
Plain-English summary
A 3-year-old Quarter horse stallion was brought in because he didn't have a left testis in the usual spot and had a larger right testis. An ultrasound showed that the left testis was actually located in the abdomen, and it revealed two unusual lines that looked like a foreign object. When the testis was surgically removed, it was found to contain two live worms called Strongylus vulgaris, which had created blood-filled tracks in the tissue. This case is notable because it's rare for these parasites to be found in a retained testis, and it also provides important ultrasound details about their presence. The treatment involved removing the testis, which successfully addressed the issue.
Abstract
A 3-year-old Quarter horse stallion with unilateral left cryptorchidism was referred for the absence of the left testis in the scrotal bursa and an enlarged right testis. The ultrasonographic examination revealed the presence of the left testis at the abdominal level. Two small hyperechogenic lines were observed running parallel and resembling a cylindrical cavitary foreign body, within a non-homogeneous area with blurred margins. The testis was removed by laparoscopy and macroscopically, the testis's cut section revealed the presence of two live adult nematodes emerging from 2 mm blood-filled tracks within the testicular parenchyma. The parasites were isolated and washed in sterile saline solution and morphologically classified as Strongylus vulgaris. Histologically, the tracks were characterized by a lymphoplasmacytic infiltrates with abundant haemorrhage invading the surrounding structures. S. vulgaris erratic migration has been reported in the retained testis of stallions, but this localization is considered uncommon; the case here reported is one of the few cases reported in the literature highlighting the rarity of S. vulgaris aberrant localization into the equine cryptorchid testis. This case also reports the ultrasonographic findings related to the parasite presence and track.
Find similar cases for your pet
PetCaseFinder finds other peer-reviewed reports of pets with the same symptoms, plus a plain-English summary of what was tried across them.
Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/40246161/