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My neutered dog has a walnut-sized lump at his penis base. What is it?

Updated on September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Male | neutered | 10 years old | 16 lbs

My 10 year old cockapoo has an enlargement at the base of his penis about the size of a walnut. He's been neutered since being a puppy. it doesn't bother him and he has normal urination.

1 Answer

Most Helpful Answer

Answered By Anna M., DVM

Veterinarian

Published on July 3rd, 2017

I'm wondering if what you are describing are your dog's bulbourethral glands. These are glands on either side of the penis that can swell, and in a dog the size of Ollie they would appear about walnut-sized. This can happen even if a dog is neutered. If this is what you're seeing, the enlargement will fluctuate in size and at times will nearly disappear.

If what you're seeing is more growth-like (and particularly if it's asymmetrical, rapidly growing, etc) then I would be more concerned about it being a possible mass, and would advise having it looked at by a vet. Hope that helps!

1Pet Parents found this answer helpful

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