My dog has a tail lump. Should it be removed or can it stay?

It looks like a histiocytoma. If it is one, it may go away on it's own without surgery. I suggest you have your vet take a look at it in person. They can advise you better after checking it. ( https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4952066 )

It does happen that cysts can refill, and if that happens it is recommended to have it removed surgically. It could be that it's starting to refill again, and you can ask your vet about having it removed surgically.

This looks like an infected cyst. Dogs have a scent area on their tails that can enlarge and get infected such as this. You can apply a hot compress to the area several times daily to see if it will drain. That will increase the blood supply to help it heal faster. Bringing Ben in for an exam would confirm a diagnosis and they would probably prescribe antibiotics which would lessen the healing time. This doesn't look like a mass to me, so it should resolve quickly with treatment. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Ben.

This lump on Alfie could be a cyst, an abscess, a benign tumor, or a malignant tumor. Any suspicious lumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of it's cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. I would have Alfie seen by a vet tomorrow to have this lump examined and diagnosed so it can be treated as needed.

Yes, I would be concerned this may be serious, especially if it has grown quickly. The broken surface is very high risk for infection and I recommend an urgent assessment by your vet; biopsy and possible tail amputation may be required. In some male dogs, a hormone dependent condition can cause similar masses and castration can be helpful in these situations

I'm glad to hear that this lesion isn't bothering Benji! It's certainly possible that this lesion is a benign papilloma-like lesion, but it could also be another benign or malignant type of mass. The only way to know for sure is to perform a biopsy of the lesion for pathologist evaluation, or at the very least, your vet could draw a few cells out with a needle for microscopic evaluation (fine needle aspiration). The tricky part with lumps and bumps on legs is that they're more difficult to remove if they grow because there is less extra skin that can be used to close surgically. For this reason in particular, I recommend taking Benji to your vet sooner rather than later to have this lesion examined in person. Even though he isn't bothered by the lesion when you touch it, I do recommend putting an e-collar (cone) on him until his appointment because the lesion looks a bit red and weepy. This can occur if he's been licking at it, even if you haven't seen him do so. I hope that he's on the mend soon!

It could be a cyst. called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of its cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. Once the cause of the lump is diagnosed, the vet can discuss treatment options if needed. Give Riley's vet a call to make him an appointment. Best of luck.