Testicular Cancer- warning graphic photos.

I had a fun (for me) surgery today involving a ten year old, mixed breed dog named Prince. His owner noticed that his testicles had grown suddenly. It turns out that only his right testicle had grown and it was about 10x the size of the left one.  He had also developed gynecomastia, or enlarged mammary tissue.  This makes the mass most likely to be a seminoma or a sertoli cell tumor.  Testicular cancer is very common in intact male dogs.  One study showed 27% of intact male dogs will develop testicular cancer.  Dogs that are cryptorchid (have a testicle that did not descend from the abdomen into the

There are 3 common types of testicular cancer in dogs.  Seminomas, sertoli cell tumors, and Interstitial (Leydig) cell tumors.

• Seminomas arise from the cells in the testicle that produce sperm.  They can cause feminization (such as gynecomastia) from the production of estrogens.  They are very slow to metastasize.
• Interstitial cell tumors arise from the cells in the testicle responsible for the production of testosterone.  They are often small and an incidental finding.  They rarely spread or cause a problem.
• Sertoli cell tumors are the more aggressive tumor and are more likely to metastasize, but even then only about 15-20% do.  They can produce large amounts of estrogen that can cause severe bone marrow suppression leading to anemia (low red blood cells).  The estrogen can also cause the feminization in the male dog.

We removed Prince's mass today and are hoping that it had not spread to other parts of his body.  We could have taken radiographs and done an ultrasound to look for metastasis, but his owners were more interested in keeping him comfortable and getting rid of the mass that was bothering him.  If the mass is malignant then at least he will feel good for a while.

The surgery was performed a little differently than a regular neuter.  In a regular neuter we don't like to go through the scrotum because they tend to be very vascular and can bleed a lot.  In this case we had no choice but to go through the scrotum.  I also removed the scrotum to prevent possible post-op complications.

 The first image is of the normal left testicle (bottom) next to the testicular mass (top).  The testicles are both still within the testiculat tunic.  The second image is of the actual mass once it has been removed from the tunic.  The large white area is the actual testis.  The slightly darker pink area on top is the epididymis.  The large red cord on the right is pampiniform plexus which is a bunch of blood vessels that supply the testicle with blood. 

Prince is recovering well and is hopefully now cured!