Clinical, cytogenetic and hormonal findings in a stallion with hypospadias--a case report.
Authors: Bleul U, Theiss F, Rütten M, Kähn W
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Hypospadias—a congenital misdirection of the urethral opening—remains exceptionally uncommon in equine practice, making this case of a three-year-old Friesian stallion clinically instructive. Clinical inspection revealed characteristic ventral penile deviation with an incompletely developed glans and a 4 cm slit-like urethral opening covered by mucous membrane, accompanied by an unusual fold of skin extending from the perineum. Despite these marked anatomical defects, hormonal assessment via hCG stimulation demonstrated entirely normal testosterone and estrogen sulphate responses, whilst cytogenetic analysis confirmed a normal karyotype (2n=64) and subsequent histopathology revealed structurally sound testicular tissue—indicating that the condition was purely anatomical rather than endocrine or chromosomal in origin. The underlying aetiology could not be definitively established in this animal, though the normal hormonal profile and genetic material suggest the defect arose during embryological penile development independent of systemic dysfunction. For practitioners, this case underscores that congenital penile abnormalities in stallions warrant comprehensive investigation including endocrine and genetic screening, though such cases will likely necessitate castration given the implications for breeding soundness and potential urination difficulties.
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Practical Takeaways
- •Hypospadias is rare in stallions but should be considered in the differential diagnosis of stallions with abnormal penile anatomy or breeding difficulties.
- •Normal endocrine function and chromosome analysis do not rule out hypospadias, suggesting the condition may result from local developmental factors rather than systemic hormonal or genetic abnormalities.
- •Castration may be an appropriate management option for affected stallions with this congenital abnormality.
Key Findings
- •A three-year-old Friesian stallion presented with hypospadias characterized by ventrocaudal deviation of the penis shaft and incomplete glans penis with a 4 cm slit-like urethral opening.
- •hCG stimulation test showed normal hormone response with plasma estrogen sulfate and testosterone levels indistinguishable from normal stallions.
- •Karyotype analysis revealed normal chromosome number (2n=64) and histological testicular tissue was unremarkable.
- •Hypospadias is a rare congenital abnormality in stallions compared to other animal species and humans, with etiology remaining undetermined in this case.