Multiple Sex Cord-stromal Tumors in a Standardbred Stallion Testis.

The article discusses a case of a male horse with multiple sex cord-stromal tumors in a testis. After noticing an abnormal growth and reduced size of the left testis, a surgery was performed revealing three tumors: a large Sertoli cell tumor and two smaller mixed sex cord-stromal tumors.

Background

• A Standardbred stallion, aged 12, had shown signs of a growing mass in the left testis for the past five months. The mass growth was coupled with a notable decrease in overall left testicular size.

Initial Examination and Findings

• Detailed examination via palpation and ultrasonography of the left testis uncovered a firm, hypoechoic, clearly outlined soft tissue mass situated in the craniolateral portion of the testis.
• The measurements of the aforementioned mass were approximately 2.5 x 2.3 x 1.9 cm.
• Apart from the main mass, two smaller hypoechoic regions were observed ultrasonographically in the left testis, indicating possible multifocal/multicentric neoplasia.
• The overall volume of the affected left testis was significantly smaller (40.3 cm) compared to its healthy counterpart, the right testis (144.3 cm).

Surgery and Post-operative Findings

• Due to the possible threat of a more aggressive type of tumor, a unilateral orchiectomy (surgical removal of one testicle) was conducted.
• The surgery led to the identification of multiple soft tissue masses. The subsequent histopathologic evaluation defined the larger mass as a Sertoli cell tumor and the two smaller masses as mixed sex cord-stromal tumors, exhibiting Sertoli cell and Leydig cell differentiation.

Significance of Study

• This single-case study marks the first report of both Sertoli cell and mixed sex cord-stromal tumors occurring concurrently in a single descended equine testis.