Why is one of my male cat's testicles bigger and the other missing?

I would not be worried about it but because of that he definitely needs to be neutered. The other testicle is either in the inguinal area or still inside his abdomen. If you don't neuter him and that testicle stays inside him it is almost a 100% chance that it will turn cancerous. So, my suggestion would be to have him neutered as soon as possible. Hope this helps. Best wishes.

If he is not neutered this is likely a testicle but in a slightly abnormal location. I would be concerned that the second one is misplaced internally and he should be assessed to surgically remove this. Testicles retained in the abdomen are at increased risk of developing tumors

Neutering the cat with one testicle descended should be no problem if you let the vet know ahead of time so the vet can plan extra time to find and extract the undescended testicle. It is usually not a big problem, however sometimes the veterinarian has to open the abdomen to remove the testicle if it is not located anywhere near the inguinal ring. Just removing the descended testicle and leaving the other one behind would not be acceptable practice.

Dogs have two testicles. Soon after they are born they descend from the abdomen into the scrotum. If only one has descended then the other testicle is retained in the abdomen. This testicle should be surgically removed since the retained testicle can develop cancer more often than the normal testicle. Usually when he’s neutered they will remove the one in the scrotum and open him up like spaying a female to remove the other one. This can be a genetic problem so I do not recommend breeding him. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Ash.

You need to go back to the vet who did the neuter and ask for the surgery report which should say whether only one testicle was removed or both. You can also have your cat tested (blood test) for hormonal activity which will then show whether he has a hormone-producing testicle left. If that is the case, I would go back to the original vet and ask him to remove the retained testicle. If he only removed one testicle he should have informed you and also told you that your tom was not neutered. Retained testicles can become cancerous as well.

Housecats typically have their testicles descend fully into the scrotum by six to eight weeks of age, but it is not unheard of for this to be delayed for up to a few months in some instances. I would not operate under the assumption your kitty is a cryptorchid (no testicles in the scrotum) at this juncture, but would continue to monitor for their presence on a regular basis. Sometimes one testicle will descend but not the other. In cases where there is no sign of testicles in the scrotum and a client still wishes to neuter, testicles must be found within the abdomen or inguinal region of the body and removed surgically. This is not an extremely common procedure, but certainly one that most veterinarians will do at least a few times during their careers. It is obviously more difficult than a regular cat neuter, since you don't know precisely where the testicles are located anatomically. Anyway, my advise is that you should keep checking and be sure to have your vet verify your findings. Sometimes their testicles can be extremely small at this young of an age. Hope this makes sense.

Hi there. If you don't want to neuter him, then yes - I would recommend having the abdominal testicle removed, and leaving the other one alone. The abdominal testicle needs to be removed because it will likely develop into a testicular tumor later on in life if it's not taken out.