It must be very scary to discover a lump on your pet especially if it a decent size. I ask you not to panic and I hope this post will guide you on what to do next. I will be including lots of pictures and some may not be so pretty.
The rule of thumb with lumps is if it is growing too quickly and bothering your pet (appears red or inflamed) then it needs to be attended to immediately. However, this does not apply to all lumps. Some skin tumors can be slow growing but may still have a potential to spread to other areas. Bottom line, if you notice a lump on your pet, then get it checked out by your local veterinarian, better be safe than sorry!
Your veterinarian should always offer to do a fine needle aspirate to identify the lump as palpation alone is not diagnostic.
Some lumps don’t aspirate well and so a diagnosis can’t be made without collecting a biopsy sample. I routinely do fine needle aspirates on lumps and if I can’t identify the cells under the microscope, then I recommend sending off the sample to the pathologist or collecting a biopsy sample. Otherwise, you have the choice of measuring the lump and keeping a very close eye on it and it if starts to grow quickly then book in your pet for surgical removal of the lump.
Lipomas
In geriatric patients, fatty lumps or ‘lipomas’ are quite common. It is an abnormal deposit of fat under the skin and we aren’t exactly sure of what instigates their development. Overweight patients and certain breeds like Labradors, Golden retrievers and Corgis seem to be quite prone to developing this type of lump. They are usually soft and unattached to the underlying tissue and benign. Lipomas are easily diagnosed with a fine needle aspirate.
This is a lipoma examined under the microscope. It appears like water droplets on a slide.
These lumps must be closely monitored as they can occasionally become cancerous. We don’t often resect these lumps as they generally recur. However, if they are causing discomfort for our patients or impeding their mobility due to their location or size e.g. in the axillary region (constant friction), then we recommend removing them. We also surgically remove them if they grow too big as they can burst. Occasionally, they can grow between muscles and feel quite hard and be mistaken for nasty lumps.
The take home massage is just because ‘lipomas’ are common in geriatrics, it does not mean we must assume it is one without getting it checked and that includes a fine needle aspirate being performed.
One of my most adorable geriatric patients came in as his owner noticed a sudden growth over his shoulder. It was not painful but had grown very rapidly and was quite large; about the size of a soccer ball. Palpation revealed it was a very hard lump and the fine needle aspirate was inconclusive. We proceeded with immediate surgery to investigate the lump.
Oscar the 10 year labrador
Oscar under general anesthetic investigating his very large hard lump.
This is an inside view of Oscar’s lump. At that stage, I was still very concerned and collected a biopsy sample and sent it off to the pathologist. Thankfully it turned out to be a lipoma.
Histiocyte
Another very common lump that usually affects young dogs is a ‘histiocytoma’ or ‘histiocyte’. This is an allergic type of benign tumor that mostly occurs in younger dogs. They take the form of raised fur-less reddened lumps. On gross examination, they are indistinct to ‘mast cells’ which are very nasty tumors
It is important to confirm they are histiocytes and that would involve sending either a fine needle aspirate or biopsy sample to a pathologist to examine. Generally they spontaneously resolve after a few weeks.
I tend to prescribe antihistamine for patients with this type of lump as it will help reduce the irritation and itching associated with it.
‘Simba’ is a 2 year old golden retriever that developed a 5 cent piece reddened fur-less lump under his jaw. It was itchy and that’s how the owner noticed it. We collected fine needle aspirates and sent them away to the pathologist and results came back confirming it is very likely a histiocyte. The lump disappeared on its own.
This young jack russell terrier presented to me with this lump under its right eye and it was at a very tricky spot if surgical resection was required. I proceeded with a full general anesthetic and collected a biopsy sample of the lump. I needed a definitive diagnosis of the lump and the fine needle aspirates would not have been sufficient. Thankfully results confirmed it was a histiocyte and it also disappeared on its own.
‘Penny’ was only 6 months old and she suddenly developed a reddened fur-less lump over her right shoulder that kept growing rapidly until it reached the size of a lemon. We proceeded with surgical resection of the lump and sent off a biopsy sample from it which confirmed it was a histiocyte. This is a picture of her after she had recovered from her surgery. The scar is the war wound she was left with after her surgery.
Mast cell
Now I would like to talk about the dreaded ‘mast cell’ as this is one of the most common cancerous skin lumps in dogs. In my experience, these tumors can come in all shapes, sizes and forms. They can be irritating and sometimes they can appear quite inactive. I don’t think this tumor fulfills its typical textbook description. I always offer to do fine needle aspirates on any lumps discovered on your dog or cat to rule in/out a mast cell. I often diagnose mast cells on fine needle aspirates. In any case, the next step after that would be resection of the lump with a decent margin (minimum of 1.5-2 cm) and sending it off to the pathologist. For those mast cells in very difficult locations like distal limbs or high grade ones, I give the owners the option of taking their pet to a specialist for complete resection.
The specialists have the advantage of advanced imaging like CT which will delineate the margins of the mast cell and if it has already spread.
‘Ella’ is a 6 year old female desexed fox terrier cross in premium health. She presented to me for a swelling over her right elbow that would spontaneously shrink then bulge.
My examination of the affected area made me suspect she had a joint issue. Xrays were absolutely normal so I proceeded to collect a fine needle aspirate of her lump and this is a picture of the sample under the microscope. I was actually shocked to discover it was a mast cell as it didn’t fit the typical presentation.
In the pictures below, the densely purple cells with purple granules are the mast cells.
As for ‘Charlie’, he sure has been unlucky in that he has had 3 mast cells resected from him over the past 2-3 years. His first two mast cells were discovered when he was 5 years old. Thankfully his owners attended to them fairly quickly and they were all completely removed.
This is ‘Cindy’ and she is a 13 years old golden retriever that developed this very large lump fairly quickly behind her ear. My colleague proceeded with removing the lump and unfortunately an ear ablation was required for complete excision of the lump.
In cats, mast cells present in a much more diffuse manner and can be wide-spread throughout the skin of the patient. This is a picture of a geriatric cat with a very aggressive form of the mast cell tumor.
Bottom line is you should never judge a lump by the way it looks. Palpation alone is not sufficient to make a diagnosis. Your veterinarian should offer to do a fine needle aspirate for any routine lump check.
If the fine needle aspirate isn’t conclusive, then you must either closely monitor the lump or organize for it to be biopsied by your veterinarian.
I have discussed a handful of the most common skin lumps and have many more to go through. Please make sure to read the sequel to this post. And if you have any questions about the three lumps I mentioned in this blog, I’m all ears…
January 14, 2013 at 6:41 am
What a great resource, Rayya! I will definitely be sharing this with my clients who are interested in learning more about the various lumps and bumps that our pets can get. The vast majority of my FNAs turn out to be lipomas, but I know it’s still necessary to do them just in case.
January 28, 2013 at 10:50 pm
Thanks for your input Elliott. Great to hear your are going to share my post with your clients.
I have been shocked once too many times when collecting FNAs of lumps that I expect to be lipomas and turn out to be mast cells or some other nasty.
January 14, 2013 at 6:41 am
This happens so much with our pets, have seen it too many times. My sister’s dog had a big lump cut out years ago. Poor dogs. Great blog, so much info and great photos!
January 28, 2013 at 10:51 pm
Thanks heaps for your great feedback John. They recover pretty well from lump removals so that’s always terrific to see.
January 14, 2013 at 7:24 am
As always, Dr. Rayya, your information is very helpful for all of us Pups in cyberspace. Thanks for making me feel better about my lumps. The old woman Slow worries herself crazy about ‘em, but Hottie Doc says no worries so we roll with her. You’re the BEST!!
January 28, 2013 at 10:51 pm
Thanks heaps Red. Glad your mom is feeling less worried about your lumps. Lots of love
January 14, 2013 at 7:43 am
Reblogged this on Town & Country Lifelong Learners – Southeast Valley Kennel Club.
January 14, 2013 at 8:29 am
Thank you very much RAYYA that was really interesting . Please keep the information coming .
January 28, 2013 at 10:52 pm
You are most welcome Boyd. Will do
January 14, 2013 at 10:03 am
I concur – very interesting, but I honestly get nervous reading this stuff cause I want everyone to be okay!
January 28, 2013 at 10:53 pm
Hey Sherri,
You are so sweet. I am hoping my post will help prevent any major issues from occurring. If we catch the lumps early, the prognosis is improved a lot.
January 14, 2013 at 2:48 pm
Another fine article Rayya and a great resource. Look forward to the next one.
January 28, 2013 at 10:53 pm
Thanks a lot for your ongoing support.
January 14, 2013 at 3:16 pm
Great post!
Thank you for explaining the differences in the lumps and bumps our pets get – so much helpful information, Rayya.
I’m going to re-blog this and put it on my FB page for pet owners. Looking forward to the sequel to this post.
January 28, 2013 at 10:54 pm
Hey Barb,
Thank you so much for enjoying my post and sharing it on your page. I really appreciate it.
Educating pet owners is all I care about.
January 14, 2013 at 3:21 pm
Reblogged this on Passionate About Pets and commented:
Watch out for the sequel to this post.
January 14, 2013 at 7:38 pm
Absolutely great information to any pet owner.
January 28, 2013 at 10:54 pm
Thanks a lot Paul. Glad to hear.
January 15, 2013 at 5:44 pm
Reblogged this on The Fish Vet's Blog.
January 18, 2013 at 1:06 am
Thank you so much Dr. Rayya for this valuable information. You are wonderful to share your knowledge with your followers. Bless you! Hugs and nose kisses from me and my sweeties!
January 28, 2013 at 10:55 pm
Chancy, you are most welcome. Makes me so happy to hear your great feedback.
January 19, 2013 at 9:37 am
I found a lump on my dog (3 year old lab mix) last week. It was about 1 cm in diameter and very red/inflamed. The vet said it was a mast cell tumor and aspirated it to confirm this before scheduling surgery. However, the cytology report stated there were no mast cells, but a lot of inflammation and scattered sebaceous epithelial cells. It also said that the cellularity of the sample was low. Now, instead of doing surgery my vet put her on Clavamox for a week because now he is saying it might be an infection. After 2 days of antibiotics, the lump has shrunk and is no longer ulcerated, however it is still pink (it sort of looks like a bug bite now). I am wondering if we are being too conservative. I don’t want to put my dog under needlessly, but I also don’t want to “wait and see” when we could be dealing with a very aggressive cancer. My vet said that the absence of cancer cells on the aspirate was a very good sign, but from everything I have read, it doesn’t mean much. I know this is not a Q&A blog, I guess I’m just looking for more thoughts. This was a really useful post and I appreciate it.
January 28, 2013 at 10:58 pm
Thanks for sharing your experience. There is no black and white answer here. Your vet has done all the right things. He collected a fine needle aspirate and then started medications. The fact of the matter is the lump has shrunken. I think you should closely monitor the lump, measure it. If it is bothering your dog or flaring up again, then it should be biopsied/resected. I hope this information helps.
January 25, 2013 at 7:54 am
Reblogged this on Donkey Whisperer Farm Blog and commented:
Lump on pet
January 25, 2013 at 7:56 am
My oldest doggie Jewel (9) just had five growths removed all were fatty except one a tiny one on her ear. We are watching this one to make sure it does NOT turn into cancer. Thank you for writing about this!
January 28, 2013 at 10:59 pm
Dear Melody. Thanks for sharing your experience with us. I am glad Jewel mainly had fatty lump and had them all resected.
January 27, 2013 at 3:48 pm
Last summer we had two benign fatty tumors removed from our dog. The one on the right side behind the right front leg was slightly smaller than a grapefruit and required a shunt for a week afterwards for draining. The one on the left side was much smaller but more painful as it was between two muscles. The surgery was expensive but successful. It took Maggie weeks to adjust (we didn’t put her in a cone but in one of my husband’s cotton tee-shirt with a Thunder Shirt over it to keep it in place–she looked like a girl in a parochial school uniform). It took months for her wonderful rich coat to grow in where she’d been shaved. We knew from the beginning the tumors were benign, but left to grow they would have made Maggie lame. She is a rescued dog, a mixture of many strong and beautiful breeds, and we’ve had her for 11 years. We would not sentence her to an inactive life. Now she runs in the mountains with us, along trails and in streams. It was worth the price, the surgery and healing time to give her this renewed chance.
January 28, 2013 at 11:01 pm
Hey Marylin. I really appreciate you sharing Maggie’s experience with us. Like you pointed out, some lumps simply have to be removed as they can impair your dog especially if they are around joints. Glad to hear she fully recovered and you thought it was all worth it.
January 29, 2013 at 5:12 am
Reblogged this on Sand Spring Chesapeakes and commented:
Nice blog about lumps.
February 14, 2013 at 3:19 am
My first guide dog Luther was a big yellow lab and when he turned seven, he developed a lipoma just behind his left shoulder blade. Thing was freaken huge and I freaked out at first, obviously cause I did not know what the heck it was. You could clearly identify it just by looking at him, as it looked like a tennis ball, lol.
Took him to his vet where he was biopsied and all came back clear.
March 24, 2013 at 8:08 pm
So sorry about the delayed response and thank you so much for sharing your own personal experience with a lump. Very insightful.
Glad your Labrador only had a lipoma and hope it doesn’t grown any further.