Multiple Sex Cord-stromal Tumors in a Standardbred Stallion Testis.
Authors: Roxon Caroline, Slack JoAnn, Bender Susan, Burns Herb, Turner Regina
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Multiple Sex Cord-stromal Tumors in a Standardbred Stallion Testis A 12-year-old Standardbred stallion presenting with progressive left testicular enlargement and atrophy over five months provided the clinical context for this case report, which documents an unusually complex neoplastic condition. Physical examination and ultrasound imaging identified a 2.5 × 2.3 × 1.9 cm firm mass in the craniolateral testis alongside two additional smaller hypoechoic lesions, with the affected testis measuring only 40.3 cm³ compared to a normal 144.3 cm³ in the contralateral gland. Following unilateral orchiectomy, histopathology revealed a primary Sertoli cell tumour with concurrent mixed sex cord-stromal tumours (containing both Sertoli and Leydig cell components) — a combination previously unreported in equine medicine. Whilst individual sex cord-stromal tumours occur sporadically in stallions and are often clinically indolent, this case highlights that multifocal neoplasia within a single testis warrants consideration of more aggressive disease and supports surgical intervention rather than conservative management. For practitioners managing stallions with testicular masses, this report reinforces the value of detailed ultrasonographic evaluation to characterise the extent of disease, and suggests that apparently localised masses may represent part of a more widespread neoplastic process requiring more definitive treatment.
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Practical Takeaways
- •Stallions with a history of progressive testicular mass growth and decreased testicular size warrant urgent ultrasonographic evaluation and consideration of unilateral orchiectomy to prevent potential metastatic disease
- •Multiple hypoechoic regions on testicular ultrasound should raise suspicion for multifocal/multicentric neoplasia requiring histopathologic confirmation
- •This rare presentation expands the differential diagnosis for equine testicular tumors and emphasizes the importance of complete histologic examination of resected testicular tissue
Key Findings
- •A 12-year-old Standardbred stallion presented with multifocal testicular tumors including a 2.5 × 2.3 × 1.9 cm Sertoli cell tumor and two smaller mixed sex cord-stromal tumors in the left testis
- •Ultrasonography identified multiple hypoechoic regions in the left testis with severely reduced testicular volume (40.3 cm³ versus 144.3 cm³ in the right testis)
- •This is the first reported case of concurrent Sertoli cell and mixed sex cord-stromal tumors in a single descended equine testis