Plasmacytoma In Dogs

Plasmacytoma is an uncommon tumor of dogs. There are two forms, medullary and extramedullary according to whether the growth is in the bone marrow or not, respectively. Today we will be discussing extramedullary plasmacytoma. This is a continuation of our series on round cell tumors which began with canine histiocytoma, followed by canine transmissible venereal tumor.

Canine extramedullary plasmacytomas are most likely to occur on mucus membranes and/or skin. The head is a common location for them, with the areas of the face, ears and lips frequently affected. However, lesions also commonly occur on the trunk as well as the feet and toes.

Typically canine extramedullary plasmacytoma is a tumor of older dogs. They arise with the appearance of raised, red nodules. Rarely is the general health of the patient affected unless the mass is in the mouth or rectum, in which case obstruction may occur.

Differential diagnosis must include multiple myeloma, especially if systemic disability is observed.

Treatment is primarily focused on surgical excision. However, given the typical locations in which they occur, surgical excision may, by necessity, be incomplete. For example, rectal and oral lesions may not allow removal of all of a tumor mass if large quantities of tissue must be excised. Sufficient skin to close a surgical site may exist for a small foot lesion, but this is a part of the body which has little skin to spare. Large lesions may require amputation.

On the other hand, growths on the trunk usually allow for wide surgical margins, removing all of the cancerous cells. In these cases prognosis is favorable.

For plasmacytomas which cannot be completely removed surgically, chemotherapy and radiation are good treatment options for many patients.

See you tomorrow, Dr. Randolph.


  1. Our 11.5 year old bully mix had a growth removed from the back of his mouth. Came back today as plasmacytoma. Since he also had 2 teeth removed in the area, the vet can not say that she was able to completely excise it. She has been in touch with the oncologist on our next steps and what we are looking at in terms of this type of “cancer”, even though it did come back as benign. However, it’s a rapidly growing “cancer” if it was not completely excised. We are now faced with mandibular surgery, radiation (the former 2 will get good margins I’m told), medicinal (will talk more with her on all 3 on Sunday during the recheck) or do nothing. I know we won’t “do nothing” as the recurrence rate is 4-6 months. For 11.5 he’s in overall excellent health and 80 lbs of solid muscle. I always said, I would not put an animal through radiation, but I’m reading this may be the best option for this type of “cancer”. Regardless, I don’t want him in pain and to suffer. I guess we’ll see what Sunday brings after speaking with our vet at the follow up. Our furkids mean the world to us.

    • Thank you for writing, Shannon. As it happens, I sent a plasmacytoma patient to our favorite oncologist today, and he got a report with a pretty good prognosis. Fortunately for him, his growth is on the lip and can probably be excised completely. I would encourage you to be aggressive with her treatment and, when the time comes, you can let her go and avoid pain and suffering. That doesn’t mean you can’t enjoy each other in the time she has left, and keep it quality time. Thank you for reading

  2. My Cairn, Tucker, is 7.5 yrs old and had a “balloon” type mass under his tongue. Weirdest thing ever to see. On July 12th, he was scheduled to have his teeth cleaned anyway, so while under sedation, so the vet removed the growth. Tucker did great. The pathology report came back as plasma cell tumor. We’re hoping it doesn’t come back, as she feels she got all of it, but in such a small area, could not get as much extra tissue out as would have been desired. He’s really a trouper and honestly acting just fine, other than being much more clingy to me than usual.

  3. Our dog was recently diagnosed with a plasmacytoma on the skin of his ankle. The FNA cytology report noted it had moderate metastatic potential. Our vet has recommended we have it removed and we have an appointment with a surgery specialist this week. My question is if we do have this removed, and it recurs or metasticises, is this a fatal condition or one that would simply mean more skin lesions needing removal and radiation/chemotherapy treatment? Our dog is 4 years old and well of course be willing to get him whatever care is recommended, I’m just unclear how grave the prognosis could possibly be.

    • Every patient is unique, and every case of plasmacytoma is unique. You need an oncologist. There may be one in the specialty practice where your surgeon works. If not, unless your surgeon has special training in oncology, if you want what’s best for your pet, consult with an oncologist first and get your questions answered. Thanks for reading

  4. Hi there
    Thanks for all the info in this article. My 11 year old jack Russell terrier had this bump growing at the top of her left front legs…it grew really fast within one month or so. She has warts all over so at first I thought it might be that. My vet today examined it and she took a sample and then came back 5 mins after and told me it’s concerning because she sees plasma cells in the sample. She didn’t really tell me what my dog has but told me we could either watch it or remove it and she recommends removing it. I have her scheduled for surgery in 5 days. She said it’s an option after to send it to a lab to see if it has any signs that it may have spread anywhere although it’s very unlikely because she said whatever my dog has tends to be local.
    Should I have it tested? What do you think this is…and is surgery a good idea?

    • It’s going to be difficult for me to say what your dog has, since he’s there and I’m here and I haven’t examined your baby. Even if you sent us a picture, we probably wouldn’t be able to tell more. But, here’s what I can say. A pathologist can sometimes tell more about a Fine Needle Aspirate than a general practitioner. After all, they have special training to be pathologists. Doing so might give you a better idea of what you’re dealing with before surgery. On the other hand, your local doctor might be really darn good at cytology and know as much as the pathologist. When you read the article, you will see that there are limitations to FNA. Knowing what you’re dealing with in advance can be a big help, as it can tell the surgeon how aggressive she should be to obtain clear margins. I’ve written quite a bit about margins, so you are likely to obtain more information by using all of those links. By all means, please do not skip histopathology on the excised tissue. You might kick yourself later if you skip that. The question of whether to perform surgery is a discussion between you and your local veterinarian. She knows your dog best. We would love to have a report on your baby after the surgery and pathologist’s report comes back. We will say a prayer for him. And one for you. Thank you for reading

      • Thanks for the reply!
        We removed the lump today and river did very well in the surgery. She has 6 staples now that we have to keep in for 14 days. The vet told us they keep the specimen for a year so we have time to think about testing it or not. We talked about it again and she said we don’t really have to because in most cases this is just confined to one spot. I want to do it anyway even though my mom is against it. I’ll probably just get them to send it out…better safe than sorry.
        I will keep you posted and thanks for the prayers.
        I saw two families putting their dogs to sleep today and it was heart breaking…this is what is pushing me more to test the lump. A few more years with river would always be great and knowing a problem a head of time would help.

  5. Dr. Randolph,
    I have found this website to be very informative and compassionate. My 10 yr. 9mo’s yellow lab was diagnosed with a plasmacytoma on her right upper side about midway between her front and rear leg. This was confirmed by my vet via fine-needle aspirate & cytology. Today is Wednesday and Lumpectomy is scheduled for Tuesday morning. Reading articles on this site have reassured me that I am taking appropriate measures to extend my relationship with my four legged friend. I know that she is coming to the end of a normal lab lifespan but if I can gain more quality time together it will be priceless. Thanks for the opportunity to share these events and how I am feeling.

      • Hannah had her tumor removed 1.3.17. It was oval shaped and approximately 3″x2″X1″. Some of the muscle that is used for twitching the back had to be removed. The tumor is on the way to pathology in Marshfield, WI. We will know the results in 5-7 days. Two drain tubes were installed so that requires keeping clean. I purchased a 6 pack of Hanes Tagless White V-Neck T-Shirts to cover and collect drainage. The extra at the bottom of the shirt is bunched and tied off with a rubber band. She is on two pain Med’s and one antibiotic. She is eating, going to the bathroom and resting comfortably. To give Med’s I use small pieces of bread with peanut butter. I bury the pill or capsule and make sure to stick the peanut butter directly on the tongue (upside down). Works great! We are awaiting the results from the pathologist to determine our next course of action. Thanks for your prayers!

  6. My Dixie, a Boxer, had mast cell cancer that was ulcerous and fast growing in the lower abdomen region 6 months ago and there was enough skin to cut out the tumor and large areas around it and the vet said he was able to get good clearance around the entire area.

    Dixie healed up and has been a perky, happy little 8 year old. Last Thursday I found another lump at her rear mammary gland that is hard and the size of an egg, it came up over night. We took her back to the vet, ran blood work, aspirated the lump, took x rays (chest and such) and will be getting an ultrasound tomorrow. The vet suspects this is in her lymph nodes and I fear the worst.

    I too worry about Quality of life over quantity of life and will choose Quality. I am so scared right now. We lost Dixie’s mate to a sudden heart attack at 10 just a year ago and we are All still reeling from losing Mr. Merlin.

    I worry about choosing more surgery if that is an option and leaving her in pain, choosing chemo and if so what type, will I make her miserable until she dies or do nothing except pain medication when needed until we know we must say goodbye to our precious Dixie. I am lost and I do not know what to do.

    • Dear Boxer 1, No doubt you will be facing some challenging decisions in the next few days. Mast Cell Tumor is very challenging because it is so unpredictable. First, don’t rule out chemotherapy until you click here and read this post on chemotherapy. If you have not done so yet, click here to read our post on Mast Cell Tumor. Your local veterinarian may refer you to a veterinary oncology specialist, or he may consult with a specialist to determine the best treatment. I believe you are correct to choose quality of life over quantity, but don’t be too hasty to count Dixie out before she has had sufficient treatment and opportunities to heal. And, please keep us posted on Dixie’s progress through this Comment section. We will all be waiting for your replies. Best wishes, Dr. Randolph.

  7. Hi,
    Thank you for this informative post! Our dog Ella was diagnosed two days ago with a round cell plasmacytoma on her chin. She’s an 11 year old viszla with Addisons Disease thus she is on prednisone and Vcortin. I’m concerned about putting her through surgery (she went through surgery 6 months ago for another cancer that was on her head). If we left it what are the odds of it ulcerating? And what else could/ would happen?
    Thanks for the help!

    • Cortney, the challenge here is that surgical removal of plasmacytomas is first-line treatment. If the mass is small enough to excise completely Ella may not have to deal with it again. If the lesion is close to the mucocutaneous junction (where the skin meets the mucus membranes of the mouth), complete excision may be more challenging. I’m not sure why you are concerned about ulceration, but a board-certified veterinary oncologist could better answer that question. Please keep us posted on Ella’s progress and your decision-making process. Sincerely, Dr. Randolph.

  8. Today our 5 and a half month old pug was diagnosed with plasmacytoma. It is on the top side of his paw. The veterinarian suggested we wait a month and see what it does. He said if it gets bigger or starts to bother him then surgery is the best option. I trust the veterinarian’s wisdom but was wondering if I should get a second opinion. He did a needle slide stain. Does this test show a definitive diagnosis or is there room for error? It really does not bother him, but I have already grown attached to him and want to make the best decision in his treatment. Thanks!

    • I don’t like going against what the attending veterinarian is saying because he’s there with your dog and I’m not. My three concerns would be echoed by what I wrote above: “Typically canine extramedullary plasmacytoma is a tumor of older dogs.” Are we 100% sure this is a plasmacytoma?

      And “Treatment is primarily focused on surgical excision. However, given the typical locations in which they occur, surgical excision may, by necessity, be incomplete.” and “Large lesions may require amputation.” Lesions on the feet are typically difficult to remove because there is so little skin to cover the resulting defect. Removing them early, while they are small, allows the best chance for complete surgical excision with clean margins and complete closure of the defect.

      Ultimately, it is up to you as to how aggressive you want to be with your pet. It is up to your veterinarian whether he wants to be as aggressive as you want him to be, or whether he declines the opportunity to perform surgery.

      Still, Step One is to be as sure as we can be about the cell type.

  9. Hi. I appreciate the article. Thank you. I recently had a fine needle aspiration of the 1 cm raised red lump that appeared on the skin of my dog’s lower chest area. Cytology came back as a cutaneous plasmacytoma. I will be having it removed in the next month. My quick question: As you mentioned that this is an uncommon tumor and my dog is 4 years old, in your opinion do you think this could be a sign of more problems to come? Or did it just happen to be a random occurrence with her age?

    • Alison, I don’t think anyone is going so far out on a limb as to say your pet is never going to have problems with plasmacytoma again. The pathologist is going to be your best source for information here. Ask your local doctor these questions after the histopathology report comes back. One concern is, “Why did my dog develop a neoplasm that is more common in older dogs at such a young age?” That question might not have an answer. The best news of all, as I see it, is the location of the mass. Your veterinarian can be very aggressive in his excision of the mass, being sure to take advantage of the plentiful skin in that site to provide wide margins. Doing so will at least make it less likely that the plasmacytoma comes back in the same site. All of our readers and I will be waiting to hear the report, so please share with us when the surgery is finished and the pathologist’s report arrives. Best wishes, Dr. Randolph.

      • I decided to have it removed last Thursday but I ended up opting out of more pathology. My dog ended up removing her sutures on Friday. So we were back at the vet on Saturday. He ended up putting in extra stitches. As I can’t get my dog (an Italian Greyhound) to wear an e-collar (I can tie it to the point of where I am worried it might be too tight but she can still get it off in a few minutes) or sit still I received some sedatives to use when I leave the house. Anyway, I am relieved to have it gone. It was frightening to see how fast the plasmacytoma grew over a couple weeks. If it ever happened again, I would get it removed as soon as possible.

  10. My Tucker (almost 10) had burrs in his foot. I thought I had them. Soon after a mass developed in his foot. Vet said plasmacytoma and removed it along with one pad. He did well. About three weeks later a reoccurrence. We have just finished Alkernan (w/Predrisone) and it doesn’t seem to have helped (for one week). I really don’t want more of his foot removed. Any recommendations? Thanks. I can’t give up on him he was by my side every day with cancer and was a big help.

    • Nancy, you need more help than we can give Tucker by “remote control.” Tucker needs a referral to an oncologist, a specialist in cancer treatment. You had an oncologist when you had cancer, now it’s Tucker’s turn. Specialists require a referral, and your local doctor can recommend someone within driving distance of your home. Please let us know how Tucker does. We will say a prayer for him and will be eager to hear back from you. Sincerely, Dr. Randolph.

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