Lady Lumps

My patient today was a mature unspayed feline and was presented to me for an open wound on her abdomen.  Upon closer exam, the wound was actually a large mass that was necrotic in the center.  There were multiple other smaller masses along the mammary chain.  Palpation of the abdomen also suggested other large masses internally.  The diagnosis was breast cancer with likely metastasis.  The prognosis was grave.  The result was euthanasia. 

Today we will be thankful for this precious life and use its body by way of necropsy to learn about breast cancer in pets.

In the above picture, the abdomen has been shaved for a better view of the masses.  Just above the last set of nipples is the open wound.  This mass is the size of a ping pong ball and has erupted through the skin.  Malignant masses often grow rapidly.  In so doing, they outgrow their own blood supply.  The result is that the center of the mass dies.  This is easily visible in the above picture.  The cheesy-looking center of the pink mass is the necrotic tissue.  There are approximately 15 other smaller masses under the skin just above (cranial to) the next set of nipples.  The masses feel like small firm pebbles under the skin.

When we open this cat's abdomen, we see multiple small tumors invading the liver.  The liver is the dark red organ.  The tumors are visible as tan colored masses on the liver.  This process is called metastasis.  Each malignancy has a preferred method of spreading.  Breast cancer prefers to spread to the lymph nodes, liver, lungs, bones, and sometimes brain.  There was a mass the size of a lemon on the portion of this cat's liver that is near the right kidney. 

Initially when I opened this cat's chest and was looking at the ventral surfaces, I thought the lungs were spared of this cancer.  But when I removed the lungs and examined the dorsal surfaces, I could see many small and large tumors.  These tumors are again visible as tan growths on the pink lungs.  When I felt the lungs between my thumb and forefinger, the tumors were palpable throughout the lung tissue and, again, felt like small pebbles. 

Sadly, this terrible malignancy could have been prevented for this pet.  As I mentioned in the first line of this blog, this pet was an unspayed female.  Current research supports that had this pet been spayed prior to puberty, there is a greater than ninety nine percent chance that she would have never developed this disease.  This percentage falls to ninety two percent after the first heat cycle and rapidly descends with each cycle that follows. 

Mammary cancer is just another reason to spay and neuter your pets and is also the reason the recommendation has changed from "we like them to go through at least one heat cycle" to "we like to spay them before they come in heat."  Even if you have a mature unspayed female cat or dog, it is never to late to spay. 

Don't just prevent litters.  Prevent breast cancer!