Buddy, a very nice, generally healthy 9 year old male Soft Coated Wheaten Terrier presented to our clinic for a ruptured cyst on his back. During his exam it was also noted that all of his nipples were very large, as if he were a nursing female (pictured). This is know as feminization was likely due to an increase of estrogen which in a male dog more often then not is due to a type of cancer know as a Sertoli cell. These tumor originate in testicular tissue, so his scrotum was examined where no testicles were found however his record and owner indicated he had never been neutered. Clearly, Buddy was cryptorchid meaning, that the testes never descended into his scrotum and his testicles were palpable in his groin area. They had never dropped into his scrotum and the right testicle (pictured) was significantly larger than the left.
Now there were two problems, the ruptured cyst and his cryptorchid cancerous testicle. He was placed on antibiotics for his cyst and surgery was schedule to remove the cyst and testicles. The surgery was successful and the biopsy of the right testicle as expected came back Sertoli Cell Tumor.
Luckily for Buddy, vast majority of Sertoli cell tumors are benign. There is an increased occurrence of this tumor in older animals, especially in cryptorchid testicles. Estrogen secretion appears in 20-30% of tumors and leads to feminization, bone marrow suppression and squamous metaplasia of the prostate. Metastasis is rare and affects the draining lymph nodes as well as internal organs.