Testicular Tumors in Dogs: Common Neoplasms in Intact Males

Testicular tumors are among the most common neoplasms in intact male dogs, with most being benign but requiring monitoring and often surgical management.

Key Facts

Testicular tumors include Sertoli cell tumors, seminomas, and interstitial cell tumors in approximately equal proportions
Cryptorchid (retained) testicles have 10-14 times higher tumor risk than normally descended testicles
Sertoli cell tumors cause feminization syndrome through estrogen secretion in some cases
Feminization signs include gynecomastia, alopecia, and attractiveness to other male dogs
Most testicular tumors are benign - metastatic disease occurs in approximately 10-20% of Sertoli cell tumors
Castration is curative for unilateral tumors affecting a single testicle
Annual testicular palpation during wellness visits detects tumors at earlier, more manageable stages

Welfare Considerations

Testicular tumors cause welfare impact both through the tumor itself and through hormonal effects - feminization syndrome causes discomfort, altered behavior, and social difficulties with other dogs. Sertoli cell tumor-related bone marrow suppression causes severe anemia and immune compromise. Early detection through regular palpation enables surgical removal before systemic effects develop. Castration of cryptorchid dogs before tumor development is the most effective welfare intervention available, preventing the substantially elevated tumor risk in retained testicles.

What You Can Do

Have intact male dogs examined annually with testicular palpation from 5 years of age
Consider castration of cryptorchid dogs before tumor development given the substantially higher risk
Present promptly if you notice testicular asymmetry, swelling, or feminization signs
Request complete blood count if feminization is present - bone marrow suppression requires urgent management
Proceed with castration promptly for diagnosed tumors - most are curable with early surgery
Monitor the contralateral testicle after unilateral tumor removal - bilateral disease occurs in some cases
Discuss castration timing and options with your vet for intact dogs over 5 years of age