Breast Tumors in Dogs

Mammary or breast masses in dogs are a fairly common finding in our older patients (> 7 years for most breeds). 


On average, approximately 50% are benign and 50% are malignant, meaning they have the chance to recur, spread to other glands and/or spread (metastasize) to other areas of the body. This is most often the lungs.


If they are isolated masses, we can do a lumpectomy and just remove THAT mass. If there are multiple masses, we may remove one or both "chains" -so all the glands on that side. This is obviously more invasive and painful. 


In addition, if your dog is not spayed at the time of this surgery, we will spay her. Mammary masses develop because of hormonal influences. This is why spaying BEFORE the first heat and even to a large degree after the first but BEFORE the second, reduces mammary mass incidence by nearly 99%!


The pictures below show the mass, which was located in the left inguinal area and involved the very last mammary gland. It was a firm but not deeply attached mass that still had a very good amount of vascular involvement (a lot of blood vessels needed to be tied off) and we place a drain post op to help with fluid and blood that often oozes post op for a few days.

The following pictures are not for the squeamish so be fore-warned:

This shows one of the cystic ovaries - both had large cysts on them!

The mass was filled with a very dark slightly thick fluid in a few "chambers"

I will post the pathology report on this mass once we get it back.

This dog was from a cruelty case and was taken in by the foster family to have a forever home. She had pneumonia and was severely underweight when she was brought to us late last year and made a full recovery. 

Let's hope she keeps going strong! 


June 23: This tumor turned out to be a malignant (bad) one: a mammary adenocarcinoma. The dog is healing well. The pathology report indicates complete excision with clear margins and no evidence of cancer cells into the surrounding vessels. However, as with any malignancy, there can be spread before we "see" it - so this dog will need periodic follow up chest X-rays and a close monitoring of her entire mammary chain.