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My dog has a suddenly growing leg bump with black spots. What is it?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Large (61lb +) | Female | spayed | 6 years and 6 months old | 75 lbs

Hello. My dog has a swelling almost the size of a dime on her left hind leg. It's been a small bump there (almost like a nipple) for about 2 years. Just recently it got much bigger and these black dots appeared. The first 2 pictures are of what's in the leg. The third picture is on her nipple. She has two nipples that have the black spots around the base of them. She's a pit bull American bull dog mixed and always had common skin rashes, I am more concerned about these.

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2 Answers

Most Helpful Answer

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Answered By Emily, DVM

Veterinarian

Published on June 9th, 2017

This could indicate this mass has an infection as well as there recent enlargement could mean it is more serious than a benign growth. If so getting it removed sooner rather than later is a good plan. If possible Tahki should get checked out by her veterinarian and this mass could be examined more intensively to determine what exactly it is and if surgery to remove it is needed. If that is not possible monitoring it for further changes and applying a thin layer of an antibiotic ointment may help.

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    Answered By Jennifer Summerfield, DVM CPDT-KA

    Veterinarian, Certified Dog Trainer

    Published on November 22nd, 2016

    Since it sounds like this mass has been present for a while and is getting larger, I would strongly recommend having it checked by a vet - it could be something fairly harmless like an infection or a benign growth, but it could also be a form of skin cancer. Your vet can do a simple test called a fine needle aspirate to find out for sure what it is - this is a quick, painless procedure that involves poking the mass with a small needle to collect some cells for analysis. Based on the results, your vet can tell you whether the mass needs to be surgically removed, or if some other kind of treatment (such as antibiotics or anti-inflammatory meds) may be needed.

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