Two Easy Ways to Start Earning Rewards!
Become a member today!
Members-only pricing and offers, personalized care notifications, Vital Care points back on every purchase and more!
Already a member? Sign in
Become a credit card member today!
Earn 2X Pals Rewards points at Petco
when you use Petco Pay!
APPLY NOW
Learn More About Petco Pay Benefits

My dog has a new, red, hard lump in his armpit. Should I worry?

Updated on September 23rd, 2025

Pet's info: Dog | Mixed Breed Large (61lb +) | Male | unneutered | 2 years old | 70 lbs

My Shepard mix has a medium sized, red, hard lump on his "arm pit". It doesn't seem to hurt but it is concerning as it popped up out of nowhere.

2 Answers

Most Helpful Answer

Answered By Ricardo Fernandez, DVM

Veterinarian, Veterinary Oncology Resident

Published on October 12th, 2017

Thanks for using Petco Pet Education Center, formerly Petcoach! Based on its appearance, this could be a benign or malignant mass. This is most of the time differentiated with a test called a fine needle aspirate which is easy, cheap and pain-free. Sometimes, a biopsy is required for a diagnosis. Have Panzer evaluated by your veterinarian to have this test performed to try to sort out what the diagnosis is so that the best course of action can be determined. Keeping my fingers crossed that it is something benign!

2Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Ricardo Fernandez, DVM
Veterinarian, Veterinary Oncology Resident
Published on July 5th, 2018
Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. There is no way of knowing what it is just based on its appearance. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!
1Pet Parents found this answer helpful

Smart Picks for Smart Questions

Related Questions

Health & Wellness

What is this painful pink lump on my 3-month-old puppy's armpit?

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. Given his young age, this could just be a small abscess or site of infection. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have him evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!

Updated on September 23rd, 2025

My pitbull has a hard, red lump on his chest. Could it be a tumor?

Thanks for using Petco Pet Education Center, formerly Petcoach! Being benign vs. malignant is more based on how it looks under the microscope. It can still be benign even if it is not very movable. This could be a benign or malignant growth. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have him evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good night!

Updated on September 23rd, 2025

Health & Wellness

My dog has swollen armpit lumps and a genital wart. Is it serious?

Thanks for using Petco Pet Education Center, formerly Petcoach! These could be benign or malignant growths. There is no way of knowing what it is just based on its appearance. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!

Updated on September 23rd, 2025

Health & Wellness

My dog has a soft lump in her armpit that changed. Is it serious?

Thank you for submitting your question regarding Ella. It is not likely an emergency, but I do recommend having the bump evaluated by her veterinarian. It appears small and hopefully is just a benign growth. Her veterinarian will likely perform a procedure known as a fine needle aspirate to determine if the bump is benign or not. The veterinarian will use a small needle to collect a sample of cells to evaluate under the microscope. Based on these results, treatment can be started if necessary. I hope this information helps!

Updated on September 23rd, 2025

My 1-year-old dog has a growing pimple in her armpit. What is it?

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good night!

Updated on September 23rd, 2025

Health & Wellness

My dog has a red, oozing lump on her chin. What is it and what to do?

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. There is no way of knowing what it is just based on its appearance. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good night!

Updated on September 23rd, 2025

Health & Wellness

My 7-month-old Pit bull mix has a new lump. Should I be worried?

Thank you for providing a picture! This could be a cyst or a benign growth. 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 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 Rocket's vet a call to make him an appointment. Best of luck.

Updated on September 23rd, 2025

Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Share