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My dog has a black fluid-filled lump on her nipple. What is it?

Updated on September 23rd, 2025

Pet's info: Dog | German Shorthaired Pointer | Female | unspayed | 35 lbs

What is this black weird sack on the nipple. It has a zit like black/brown fluid inside with a little hole at the end. The black stuff inside can be squeezed out. She has had it for a year and it havent gotten alot bigger, but a bit. Could you please tell med what it is and if it is something to be very concerned about? Is she in pain because of this?

2 Answers

Most Helpful Answer

Linda G,  MS, DVM

Answered By Linda G, MS, DVM

Veterinarian

Published on January 12th, 2022

Hello. It is difficult to say exactly what this is because cysts, small tumors & other benign skin growths can all look pretty similar. We do not recommend doing any squeezing on things like this because you could inadvertently introduce bacteria back into it & then you have a real problem. You should contact your veterinarian to schedule an appointment. Only after a hands-on examination can a plan be determined. One might be to just continue to watch this (without squeezing out the contents), or to remove it, send the tissues off for pathology, & make sure this is not something worrisome. I hope it is just benign, but it is better to know than worry. Thans for contacting Petco Pet Education Center, formerly Petcoach.
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Related Answers from Veterinarians

  • Answered By Laura Johnson VMD

    Veterinarian

    Published on April 20th, 2018

    Hi, thanks for using Petco Pet Education Center, formerly Petcoach!

    Thanks for the picture. It appears to be a growth on the nipple. If it is new or has increased in size I would have it evaluated by your Vet. It could be a benign growth like a cyst or hyperplasia of the nipple or it could be a mammary tumor. Your Vet can discuss possibly aspirating it if they are concerned or removing it for biopsy.

    I wish you the best!

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    2Pet Parents found this answer helpful

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