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What are Canine Mast Cell Tumors?

Mast cells are white blood cells involved in allergic response and inflammation. They house a substance containing histamine and heparin that can cause systemic complications when released into the bloodstream. These include allergic reactions, low blood pressure, gastrointestinal problems, and slow blood clotting in the area of the tumor. Mast cell tumors originate in the skin, then migrate to the local lymph node. From there, these tumors usually move to the liver and spleen. They can aggressively attack other body areas, such as the GI tract and bone marrow.

Mast cell tumors are the most common cutaneous tumors in dogs, accounting for 20% of all diagnosed skin tumors. These masses can occur on any part of the body, are very unpredictable, and can vary in appearance. They can often be successfully treated with removal and other therapies, but can reoccur in more progressed cases.

Canine Mast Cell Tumors Average Cost

From 303 quotes ranging from $500 - $8,000

Average Cost

$5,000

Symptoms of Canine Mast Cell Tumors in Dogs

The tumors seen in this disease can vary in appearance considerably, and include:

  • Solitary raised lumps or bumps under the skin
  • Lumps are swollen, red, or ulcerated
  • Lumps that are covered with hair or hairless
  • Itchy lumps
  • Multiple skin masses
  • Tumor that increases, then decreases in size, sometimes by tumor agitation
  • Masses with a stalk
  • Painful tumors
  • Presence of a lump for months or years without any change in size or appearance
  • Rapidly growing lumps

Symptoms other than tumors include:

  • Allergic reactions
  • Gastrointestinal ulcers
  • Vomiting
  • Anorexia
  • Bloody stools
  • Slow blood clotting in the area of the tumor

Types

Mast cell tumors are categorized into three grades and react differently in the body depending on what grade they fall under. These are: 

  • Grade I - Tumors are least aggressive in this grade and are often confined to the skin. These tumors can be cured with surgical removal

  • Grade II – Tumors are in skin, and can be aggressive, spreading into lymph nodes, liver, spleen and bone marrow
  • Grade III – These tumors are very aggressive, with a high level of metastasis
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Causes of Canine Mast Cell Tumors in Dogs

The actual underlying cause of mast cell tumors is unknown. There are a few factors being investigated, which include:

  • Genetic predisposition
  • Mast cell abnormalities
  • Chronic inflammation
  • Mutation of c-kit protein 

Any dog can develop mast cell tumors, but some breeds are predisposed to the condition. These include:

  • Boxers
  • Boston Terriers
  • Bulldogs
  • Pugs
  • Retriever breeds
  • Weimaraners
  • Shar-Peis
  • Rhodesian Ridgebacks
  • Cocker Spaniels
  • Schnauzers
  • Staffordshire Terriers
  • Beagles
  • Older dogs
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Diagnosis of Canine Mast Cell Tumors in Dogs

A visible skin tumor usually alerts a pet parent that there may be a problem. Your veterinarian will perform a thorough exam, focusing on any visible tumors. If your veterinarian suspects a mast cell tumor, then a fine needle aspirate biopsy is used to extract cells from the tumor. Mast cells can be identified through this biopsy.

Once it is diagnosed as a mast cell tumor, additional tests are performed to determine if it has spread to other areas of the body. These tests can include a biopsy of local lymph nodes, bloodwork, and a urinalysis. Abdominal ultrasounds and chest X-rays are used to assess the size of the lymph nodes, liver or spleen. An assessment of the bone marrow is made by collecting bone marrow cells for examination, or looking for circulating mast cells with white blood cells. These results will determine what kind of treatment is needed.

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Treatment of Canine Mast Cell Tumors in Dogs

Treatment is based on the extent of the mast cell tumors, and their predicted behavior. 

Surgical removal is the most common treatment for mast cell tumors. It is important to determine if all of the tumor was removed, because it can reoccur at the same site if any was left behind. This is found in the biopsy evaluation following surgery. A second surgery may be required to remove the rest. Before surgery, antihistamines are often prescribed to counteract the effects of the histamine released from the mast cells.

After surgery, biopsied tumors are tested and evaluated to determine what grade they fall under. The grade is an important factor in determining the rate of aggressiveness of the tumor. A grade assessment can be aided by the history of the tumor, tumor location, and the health and breed of your dog. Factors such as tumor grade, tumor spread, and if there was enough of a tissue margin to adequately excise the tumor, are all taken into consideration in deciding if your dog needs additional treatments.

Radiation therapy can be prescribed and is often used for mast cells that could not be removed. Surgery and radiation therapy are generally recommended for Grades I and II. Chemotherapy can also be recommended and is often reserved for Grade III tumors.

Medications may be prescribed to fight the secondary issues caused by the tumors. These drugs can include antihistamines, antacids, and corticosteroids like prednisone.

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Recovery of Canine Mast Cell Tumors in Dogs

Recovery is dependent on the grade of the tumor, whether the tumor was completely removed, and how much the tumor has spread.

For dogs with Grade I and II tumors, recovery is excellent after surgical removal and radiation therapy. No tumor reoccurrence within 3 years is seen for 90% to 95% of dogs. For Grade III tumors, recovery is fair, hindered by a likely tumor reoccurrence and spread. These tumors often require more aggressive treatments.

You may be prescribed medications to administer at home. Depending on the factors leading to recovery, you may need future veterinary visits for tests and treatments.

Dogs that have developed a mast cell tumor tend to develop more tumors, so watch your dog closely for the appearance of new growths. If caught when they are small, surgical removal is generally advised.

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Canine Mast Cell Tumors Average Cost

From 303 quotes ranging from $500 - $8,000

Average Cost

$5,000

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Canine Mast Cell Tumors Questions and Advice from Veterinary Professionals

Need pet health advice? Ask a vet

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Ask a Vet

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Chong

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Lab mix

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13 Years

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Moderate severity

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0 found helpful

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Moderate severity

Has Symptoms

Lump Noticed Under His Fur

My dog is 13 yrs old. He is a lab mix. He was diagnosed with a mast tumor in the area below his shoulder. He was biting at it and itching it. It is very large. He is on meds and at times it would bleed. Now it is a hole and it doesn't seem to be as big. The hole part has me confused. It no longer bleeds and he is acting fine

Sept. 4, 2018

Chong's Owner

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Gigi

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Spaniel mix

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9 Years

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Moderate severity

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Moderate severity

Has Symptoms

Lump
Cancer
Mast Cell Tumor On Haunch

We've rescued a stray from our local shelter whom they think is between 9-11 years old. She had a mammary tumor removed and at the same time, they biopsied the lump on her leg which was diagnosed as mast cell tumor. Other than that, she is happy and in good health. Since the tumor appears not to have spread, the shelter wants to operate to remove it. My concern is her advanced age. Is it worth it to put a dog through an aggressive surgery when they are this old? I just want her to have a good quality rest of her life. Thanks for your thoughts!

Aug. 28, 2018

Gigi's Owner

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Dr. Michele K. DVM

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0 Recommendations

Mast cell tumors should be removed, generally. Without knowing the extent of the tumor or the size, I'm not sure how aggressive her surgery will have to be, but getting a second opinion from a veterinarian who can see her and the mass might be a good idea.

Aug. 28, 2018

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Awezo

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Labrador Retriever

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2 Years

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Serious severity

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0 found helpful

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Serious severity

Has Symptoms

Bumps
Mass In Abdomen
Mast Cell

We found a bump on our 2.5 yr old dog (Mix of Lab, Rot, And Grt. Pyrs) in the chest area (it popped out of no where), we had it removed and it came back as Grad 2, High Mast Cell cancer. The margins came back clean, which is great. The vet said since it was Grade 2 "High" we should do an x-ray and ultra sound to see if it spread, so we did. The scans came back clean, no sign of the cancer/tumors spreading. He still recommends us talk with an oncologist as there could be microscopic cancer cells still in her, which could result in more growths. Would you recommend any chemo or steroids to try and kill any microscopic cells that haven't started to grown on her yet? What would you recommend we do?

April 16, 2018

Awezo's Owner

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0 Recommendations

Typically grade II tumours removed with clean margins carry a favourable prognosis, however your Veterinarian may have concerns that the tumour recurred once already and may do so again so a visit to an Oncologist may be good to be on the side of caution. Regards Dr Callum Turner DVM https://vth.vetmed.wsu.edu/specialties/oncology/information-for-owners/mast-cell-cancer

April 17, 2018

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Remington

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Mix

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10 Years

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Serious severity

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Serious severity

Has Symptoms

Tumor
Mast Cell
Strange Snoring

My dog was just had a tumor removed and we had a biopsy done on it. It came back as a Mast Cell Tumor grade 3. From the information I have read, this is pretty much the worst news possible. The tumor was on his snout right before his nose. Knowing that this diagnosis is not good, and not really curable, just wondering what to expect as this disease progresses.

Feb. 23, 2018

Remington's Owner

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Dr. Michele K. DVM

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0 Recommendations

Thank you for your email. Grade 3 mast cell tumors can be quite aggressive. What to expect depends on the margins of surgery, his condition, and what else might be going on with him. it would be best to follow up with your veterinarian as to what the follow up expectations are for Remington, as they know the details of the surgery, what the margins were, and what might be expected with his recovery. I hope that he does well.

Feb. 24, 2018

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Petit Loup

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Schipperke

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15 Years

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Serious severity

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2 found helpful

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Serious severity

Has Symptoms

Cancer

My dog was diagnosed with a low grade mast cell tumor that is slow growing. It is located right beside his anal hole. It is 6 mm in size. The oncologist said that upon removal they will not be able to get all the cancer cells.Radiation and chemo are not an option. Ultra sound and x ray show he has no other cancer anywhere else in his body. My two concerns: Operating to remove the cancer could aggravate the remaining cancer cells prompting them to spread through the body? 2) The area is at the anus. I have read that mast cell removal can cause the area not to heal properly. Also risk of infection from diarrhea. He needs to heal completely. What are the odds that he could encounter the inability to heal properly?

Feb. 1, 2018

Petit Loup's Owner


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2 Recommendations

Given Petit Loup’s age and location of the mast cell tumour, healing and recovery time is a concern; I cannot give you any solid statistics but healing and recovery are generally more prolonged in older animals. Generally if adequate margins cannot be taken, radiotherapy or chemotherapy is indicated especially if the tumour is high grade; it would be best to discuss this with your Oncologist as they would be more knowledgeable about Petit Loup’s case. Regards Dr Callum Turner DVM www.fitzpatrickreferrals.co.uk/conditions/canine-mast-cell-tumours/

Feb. 1, 2018

Hi! Dr. Callum Thank you for opinion about healing and recovery time. The results for my dog's Mast Cell Tumor is the decision not to proceed with any surgery. The Oncologist explained that if they were to operate they would not be able to remove all the mast cell tumors. This is because of the close proximity to the anus. There is no margin for clean removal.Some mast cell tumors would remain and continue to grow. If there was surgery, then there is a possibilty that the stitches will not heal properly due to his age and the fact there will be remaining mast cells. He would have to take antibiotics that will cause diarrhea. Would be very hard to keep the area from becoming infected with 5 stitches at his anus. Then not healing properly and infection become a viscious cycle. My dog is 15 yrs. old and he is at the maximum life span for his breed. His breed is Schipperke. The mast cell tumor is low grade and slow growing. I believe that he will experience more problems from the degenerative kidney disease that has just began rather than from the mast cell tumor. Truly, at this point it is about quality of life. I love my dog and he should not have to suffer through an operation that will not cure the cancer. He is too old and that is too much trauma.

Feb. 7, 2018

Sarah Elizabeth B.

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Bijoy

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Boston Terrier

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13 Years

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Moderate severity

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Moderate severity

Has Symptoms

Mast On Back Leg

I have a female Boston Terrier who has mast cell tumors. My vet in the USA had put her under to remove a tumor but when he shaved her, he found lots of them.. so he didn't remove the one large mast. He put her on Chemo and it went down.. He decided to take her off the chemo tablets. I am now in the UK and the mast is back. Its about the size of a 10p / Quarter. Vet her doest seem to think putting her back on the chemo tablets,... but she did so well previously.. Just wondering you thoughts.

Canine Mast Cell Tumors Average Cost

From 303 quotes ranging from $500 - $8,000

Average Cost

$5,000

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