Lumps and bumps part 1: Do you want to see a one pound lipoma?

I have learned a couple of things from blogging.  Number one, the first picture contained in a blog post is often the thumbnail that is used by other web sites when a linked back to the blog.  Number two is that some people don't enjoy looking at gross pictures of tumors and body parts.  I can't quite figure out why someone wouldn't want to look at something as fascinating as a one pound lipoma, but I accept that some people really do feel that way whenever I show someone a recently removed tumor and they turn white as a ghost and leave the room.  Oh well.  I guess the fact that I am fascinated by how things look underneath that covering of skin makes me well suited to being a surgeon.  And so to kick off this blog about tumors and lumps and bumps, I give you a picture of my dog Buddy.  He is lot cuter than a one pound lipoma anyway.

Onward to the blog about lumps.  I decided to write this blog because I have seen a few tumors lately where owners ignored a lump on their dog until the lump was so big or so aggressive that nothing could be done to save the dog's life.  I don't know quite why people wait so long, but it is not uncommon.  Sometimes it is money, but many times it is not.  Maybe it's that we all get busy with other things in our lives or there is some underlying fear that the lump may be something bad, but it is a common human reaction to put things off until they jump up and bite us.  So I thought I would share some examples of when lumps can be ignored and when they can't and how some lumps can be prevented and how some cancers in our pets can truly be cured.  Part 1 will be dedicated to benign lumps that can sometimes be left alone except when they are in bad locations or get really large.

Lumps and bumps are really common especially in dogs.  Lumps can be caused by infections (e.g. abscesses) or irritations (e.g. lick granulomas - that's a good one to type into a Google Image search) or lumps can be caused by abnormal growth of cells (tumors).  Tumors can be either benign or cancerous.

The case of the one pound lipoma

definition of lipoma = a benign tumor made of fatty tissue

Lipomas are one of the most common tumors we see in dogs.  They are benign although there is a cancerous counterpart called a liposarcoma, but those are relatively rare.  Most lipomas occur along the side or the lower part of the chest or the belly, but I have seen them on legs or the head on occasion.  One time I removed a lipoma from the side of a Labrador Retriever's head that was literally as big as the lab's head.  It looked like the dog had two heads.  This dog had been adopted from the local shelter with this growth and his new owners were kind enough to have this monstrous growth removed.  I just want to give people a big hug when they take on a senior dog from a shelter with a problem.

Some dogs get so many lipomas during their middle age to senior years that it would be impossible to remove them all.  Retrievers are especially noted for getting lots of lots of these growths as they get older. These growths are not painful, but if they grow in a bad spot, they can cause difficulty walking or moving.  Because lipomas are common growths that don't bother dogs very much, they are one type of tumor that is often left alone.  They can however get quite large.  My personal record was an 11 pound lipoma that I removed off the side of the flank of a dog.  The dog weighed (after surgery) 17 pounds.  That tumor was nearly 2/3rds of the dog's post-surgery weight.  Holy lipoma batman!

Some lipomas are soft and others have a more firm feel to them.  Some of them are quite easy to determine where they stop and where normal tissue starts.  Others "infiltrate" into normal surrounding body fat.  Through experience, most veterinarians can tell you whether they think a lump is a lipoma or not and most of the time they will be right.  But the truth is that none of us can truly know what kind of lump your pet may have without a biopsy (taking a sample of the cells from a growth and looking at them under a microscope).  And the other truth is that there are some cancerous growths that can feel identical to lipomas.  Hemangiopericytomas and mast cell tumors are two examples and those two growths can be very difficult to deal with especially if you let them get big.  I will say that I don't necessarily recommend a biopsy of every single "lipoma-like" lump, but there are times when I think it is a very good idea.

Teddy was a retriever that came to see me because his owners noticed a swelling in his upper thigh on the inside.  By feeling it I could tell it was a mass of some sort so the next step was to do a needle biopsy.  A needle biopsy (fine needle aspirate) is done by sticking a small needle into the lump and sucking out some of the cells with a syringe.  The cells can then be put on a slide and looked at under a microscope.  Needle biopsies are not nearly as accurate as taking a whole slice out of  a lump, but the nice thing is that most dogs don't need any sedation to get a needle biopsy sample.   Some tumors are really hard to diagnose with a needle biopsy but lipomas are pretty easy most of the time.  I did a needle biopsy on Teddy's lump and the report came back it was a lipoma. We decided to leave it alone for several reasons.  It was in kind of a bad spot to remove, it wasn't causing him any symptoms and because I knew it was a lipoma, I also knew that if it got a little bigger it would not be much harder to remove than it already was.

Teddy did just fine, but about 10 months later, his owners noticed that the lipoma was getting bigger and it was starting to affect how Teddy was using his rear leg.  We decided to remove the lipoma.  I was happy that this lipoma was one of the non-invasive kind and even though it was in a really bad location, it came out relatively easily.  As is typical of growths that are a little larger than average, I like to get them weighed and photographed.  And so here is a one pound lipoma hanging out next to a regular sized Sharpie for size comparison.

Even though lipomas are abnormal growths of fat cells, they are fat cells none the less. If you are carrying a little extra weight, just think about 10, 20, 30 or more of these little buggers hiding out under your skin.  I know I think about it every time I have that extra slice (or two or three) of pizza on a Saturday night.  Certainly gives me some motivation to get out and ride my bike.

Enough about lipomas.  Next blog is part 2 about lumps that should not be left alone.