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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?

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2 Answers

Most Helpful Answer

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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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    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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