Sertoli cell tumor is related with undescended testicles. It is a form of testicular tumor in dogs. A significant number of this tumor (14%) is malignant in nature and the tumor will metastasize or progress to surrounding lymph nodes and other parts of the body.
The signs and symptoms of sertoli cell tumors include:
Skin changes may become apparent
One testicle that is larger than the other, with wasting or shriveling of the other testicle
Feminization syndrome, a condition where a male dog takes on uncharacteristic female qualities (e.g., dog’s penis may shrivel or shrink in appearance, there may be abnormal breast development, and the dog may adopt a female position to urinate)
An abdominal mass may become palpable (found by touch examination) if a testicle has not descended — suggesting that the testicle remained in the abdominal cavity