Clinical Management of Testicular Tumors in Dogs.

Testicular tumors are the most common neoplasms of the canine male reproductive tract, corresponding to approximately 25% of all tumors in intact males. A large percentage of cases are characterized by one of three main tumor types: seminomas, interstitial Leydig cell tumors, or Sertoli cell tumors. Clinical importance is primarily associated with endocrine activity rather than malignant behavior; orchiectomy is the treatment of choice for most canine testicular cancers. Endocrine activity, particularly estrogen secretion, may result in feminization syndrome and, in severe cases, bone marrow suppression. The diagnostic approach combines physical examination, ultrasonography with hormonal assessment using endocrine testing (testosterone, estradiol, and T:E ratio), and/or tissue level evidence of the estrogen effect (preputial cytology). Management is centered on orchiectomy; unilateral surgery may be considered when the contralateral testis is clinically and ultrasonographically normal and when preservation of reproductive capacity or working ability is still a priority. Dogs with hormonally active tumors benefit from postoperative hematologic and endocrine monitoring. Recent advances in immunohistochemistry (IHC), such as Ki-67 and inhibin-α markers, and imaging techniques are improving tumor characterization and individualized clinical decision making.