Tumor of the Thymus in Dogs

Tumor of the Thymus in Dogs - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
Tumor of the Thymus in Dogs - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What are Tumor of the Thymus?

Thymoma is a rare tumor that most commonly affects medium to large breed dogs and is most often found in the Labrador and German Shepherd breeds. Most thymomas occur in older dogs, with the median age of 11 years. Thymomas may cause cranial caval syndrome, hypercalcemia, aspirational pneumonia, and/or myasthenia gravis.

The thymus is an organ within the lymphatic system located inside the chest cavity just in front of the heart. The thymus produces a subset of lymphocytes, or white blood cells, called T-cells, which are integral in killing foreign cells, activating other immune cells to fight infection, and ceasing the immune response once a threat has been eliminated. A thymoma is a rare tumor originating from the epithelium of the thymus, or the layer of tissue surrounding the thymus.

Tumor of the Thymus Average Cost

From 19 quotes ranging from $3,000 - $15,000

Average Cost

$8,500

Symptoms of Tumor of the Thymus in Dogs

  • Coughing
  • Labored breathing
  • Rapid breathing
  • Cranial caval syndrome: swelling of the head, neck, and forelimbs, fluid build-up in the chest
  • Myasthenia gravis: muscle weakness, enlarged esophagus, frequent regurgitation
  • Hypercalcemia (high calcium level in the blood): increased thirst, increased urination, decreased appetite, weakness, and lethargy
  • Decreased exercise tolerance
  • Difficulty swallowing
  • Weight loss
  • Paralysis of voice box
  • Aspirational pneumonia
  • Abnormal heartbeat
Types
Thymomas can be invasive or non-invasive, with each type occurring at about a 50% rate. Even more rare is a thymic carcinoma, a malignant tumor that metastasizes to other parts of the body.
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Causes of Tumor of the Thymus in Dogs

The cause of thymoma is completely unknown.

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Diagnosis of Tumor of the Thymus in Dogs

The veterinarian who you've brought your dog to will conduct a thorough physical examination of your dog and ask you to recount the onset of symptoms in order to aid diagnosis. A chemical blood profile to measure levels of proteins and calcium in the blood will reveal hypercalcemia, which affects 5% of dogs with thymoma. A complete blood count will measure red and white blood cell and platelet levels in order to detect any abnormalities and anemia, which can be found in some dogs with thymomas. Your dog’s blood will also be tested for the presence of antibodies to acetylcholine receptors, which would be a positive indicator of myasthenia gravis. Another indicator of myasthenia gravis is a Tensilon test, which for which your dog will be injected with tensilon (also called edrophonium) and his muscle movements will be tested. If your dog has myasthenia gravis, muscle strength will be improved during the test. Further, a urinalysis will measure mineral content, glucose and protein levels in your dog’s urine.

X-rays are an important diagnostic tool, and will indicate a build-up of fluid in the lungs, as well as the presence of a mass which may be in between the functioning lungs, on the thymus or in front of the heart, and the presence of an enlarged esophagus, which is a symptom of myasthenia gravis. Definitive diagnosis depends upon a biopsy of the mass, which is most commonly conducted once the mass has been entirely surgically removed and is most likely the case with thymoma. If other tumors are present, they will more likely be diagnosed through a fine-needle aspiration biopsy prior to surgery. CT scans, MRIs or chest ultrasounds may be conducted.

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Treatment of Tumor of the Thymus in Dogs

Surgery is the primary treatment for thymoma. Tumors may be removed through open surgery, during which the ribs are spread, or the breastbone is cut with a saw. However, some veterinary surgeons may offer a procedure known as VATS, or video-assisted thoracoscopic surgery, in which a camera on a thin tube, or thoracoscope, is inserted into the chest through a small incision and instruments that can remove the tumor are inserted into the chest cavity through two other small incisions. VATS is less invasive and can reduce in-hospital recovery time; however, it may not be available in your area.

Another treatment option only recommended in cases where the tumor cannot be removed surgically, is radiation, which is effective in 75% of cases. Radiation side effects include inflammation of the heart sac and lungs. Radiation treatments are administered daily for a period of 18 to 21 treatments. Chemotherapy is found to be ineffective and is not considered a viable treatment option for thymoma.

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Worried about the cost of Tumor Of Thymus treatment?

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Recovery of Tumor of the Thymus in Dogs

The prognosis for invasive thymoma is guarded, as is that of dogs receiving radiation therapy. Dogs receiving radiation therapy have a median survival time of 248 days following treatment. The prognosis for thymic carcinoma is very poor. Prognosis is also negatively affected by concurrent myasthenia gravis and aspiration pneumonia.

The prognosis for noninvasive thymoma is excellent, particularly in dogs whose thymoma is completely removed.

Regardless of the method of treatment, follow-up appointments will be scheduled in order to review x-rays and monitor the tumor’s size, and/or recurrence you're your dog does undergo surgery, management of surgical sites is incredibly important, as is easing your dog into home life after surgery. Be sure to follow all post-surgery instructions, paying special attention to guidance on diet, pain management, and activity.

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Tumor of the Thymus Average Cost

From 19 quotes ranging from $3,000 - $15,000

Average Cost

$8,500

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Tumor of the Thymus Questions and Advice from Veterinary Professionals

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Merlin

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Golden Retriever

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9 Years

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1 found helpful

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1 found helpful

Has Symptoms

Feeling Tired All The Time
Breathing Difficulty
Weight Loss

Hello, my dog Merlin is 9 years old. He’s had difficulty in breathing. That’s why we took him to his vet. We were told his heart got bigger (he was 39 kg then) and there wasn’t enough space in his chest for more air. And then his doctor found a mass on the thymus and it turned out to be benign. He was prescribed a medication to help him urinate more often and a medication for his heart. He’s been using the medication for a month, but he stopped eating 3 days ago. He was eating very little after he started medication. His doctor thinks it could be thymoma, and adds that because of Merlin’s heart issues and age, operation should be the last option. I can’t let my son go like this. What should we do at this point? Can radiation be an option? Thanks in advance.

June 26, 2018

Merlin's Owner

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1 Recommendations

Thymoma is a relatively rare tumour in dogs, but does occur; surgery is the treatment of choice, however they generally respond well to radiotherapy. You should discuss with your Veterinarian about Merlin’s suitability for radiotherapy as well as management of any other secondary condition. Regards Dr Callum Turner DVM

June 27, 2018

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Roscoe

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Red-nose Pit bull

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7 Years

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1 found helpful

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1 found helpful

Has Symptoms

Lost Appetite
Lost Apatite

Today I finally got an answer about my 7yr old pit bull. After 3 months of not knowing I got blood work done but nothing came of it. And a pancreas test was negative. I got two separate sets of X-rays done. Dr says there is a mass effect in the cranial thorax. And they think it's cancerous. But it's out of their reach. What's the best way to go about dealing with this? I have no experience?

July 26, 2017

Roscoe's Owner


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1 Recommendations

Masses in the thorax can be difficult to diagnose, manage and treat; usually surgical excision is the treatment of choice but is a costly procedure that carries a level of risk (due to opening the rib cage and requiring artificial ventilation); additionally, the invasiveness of the mass will determine if it can be removed fully. An ultrasound would be useful to get a better idea of the invasiveness and blood supply of the mass; a biopsy may also be taken during this time (guided by the ultrasound) to help to determine if the mass is malignant or not. The origin of the mass, location, invasiveness and type of cells would determine treatment and prognosis. Regards Dr Callum Turner DVM

July 26, 2017

Extremely thank you so much. I appreciate the clear and concise answer of going about dealing with Roscoe. Thank you again.

July 26, 2017

Roscoe's Owner

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Tumor of the Thymus Average Cost

From 19 quotes ranging from $3,000 - $15,000

Average Cost

$8,500

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