Download Dear Dr. Stillman, I have an 11 year old Black Lab who has a

Dear Dr. Stillman,
I have an 11 year old Black Lab who has a sizeable fatty tumor on her left side. We've had
labs before and have been told in the past they are common in labs and as long as it's soft
it's Ok. Someone mentioned having it drained and I didn't know if that was
advisable. What are your thoughts on fatty tumors and treatment?
Thanks,
Paul
Dear Paul,
You’re describing a very common condition among middle aged to older dogs. Let’s
agree on a little terminology first. When we use the word tumor to describe a lump we’re
implying that it is benign. If we’re worried that it’s not benign we call it a cancer. Benign
means that we predict that it’s not going to spread to other parts of the body or invade local
tissues. It is likely to grow slowly but we assume it’s not a fatal condition.
One of the most common tumors that we identify is a fatty tumor. We call them
Lipomas. A Lipoma is a mass of fat underneath the skin (or sometimes inside the chest or
abdomen) which arises from the cells that fat is made out of. These cells are called
Adipocytes. When Adipocytes begin to divide uncontrollably the result is the fatty mass
you’ve noticed in your dog.
Some dogs have a single large tumor and some have many small ones all over their
body surface. Cats can get them also, though they are much less common. Though
Lipomas have a very distinctive and characteristic appearance, it is important to confirm
their identity with a quick, inexpensive and painless test called cytology. In this test a
veterinarian inserts a small needle into the mass and draws back some cells into a syringe.
The cells are then smeared onto a microscope slide and examined under a microscope. Fat
cells have a very distinctive appearance and the diagnosis is usually very straightforward.
It is important to confirm the identity of the mass conclusively. Just because a mass looks
like a fatty tumor does not mean that it is benign. There are several types of cancers that
closely resemble a Lipoma.
Once the diagnosis is confirmed we can breathe a sigh of relief. I very rarely remove
these masses. The exceptions would be if they’re growing somewhere that makes the pet
uncomfortable or hampers their ability to walk or lay down comfortably (such as in their
armpit) or if it’s growing somewhere that makes the pet look strange or silly (such as on top
of their head). Sometimes, if a pet is going to be anesthetized for some other procedure
such as a dental cleaning, I’ll take advantage of the opportunity to remove a couple of
Lipomas at the same time.
Though the removal of a Lipoma is usually a quick and straightforward surgery, they
cannot be drained through a needle. Their consistency is much like jello, or the white part
of a hard-boiled egg. The tissue they are made of is not fluid enough to be drawn through
even the largest needle. My best advice is to make sure that the lumps you’ve noticed are
indeed Lipomas and once you’re sure, don’t worry about them anymore.
Be Well,
Norm