Thymoma in Dogs

Thymoma is a condition that negatively impacts a dog's thymus which is an organ that's found at the front of their hearts. The job of a thymus is to produce T lymphocytes and when a tumour develops it can lead to all sorts of problems. These cancerous growths are often associated with another condition namely myasthenia gravis which is a very serious autoimmune disorder that needs to be diagnosed and treated sooner rather than later. When a vet can successfully treat thymomas, the prognosis tends to be good, but their condition would need to be closely monitored for the remainder their lives.

Symptoms Associated with the Disorder

When dogs develop a thymoma, there are certain signs of there being something wrong and this includes the following symptoms presenting themselves:

• Coughing
• A faster rate of breathing
• Difficulty breathing
• Cranial caval syndrome - this is a condition that is bought on hy an infestation of heartworm
• Myasthenia gravis

The Causes

The exact causes of the condition remain unknown and as such more research is needed to understand why some dogs develop thymomas whereas others do not.

Diagnosing the Condition

A vet would ideally need to know a dog's full medical history and how the onset of any symptoms first presented themselves. The vet would thoroughly examine a dog suspected of having developed a thymoma and would typically recommend carrying out the following tests which would help confirm a diagnosis:

• A complete blood count
• A full biochemistry profile
• A urine analysis
• An electrolyte panel
• Thoracic X-rays which would establish if there's a build-up of lung in a dog's lung and if there's a cranial mediastinal mass in between a dog's lungs
• A tensilon test to see if a dog is suffering from myasthenia gravis
• A fine-needle aspirate of the tumour

Treatment Options

Dogs with the condition would need to be hospitalised so they can be closely monitored and prepared for a treatment a vet might have set in place to resolve the thymoma. Removing the growth can often prove challenging in dogs and if they already suffer from myasthenia gravis or aspiration pneumonia, the prognosis tends to be a lot poorer too. Studies have established that around 30% of thymomas turn out to be malignant and therefore they spread to a dog's abdomen and their chests.

Living with a Dog Suffering from a Thymoma

If the vet can successively remove the tumour through surgery and the problem has not spread to other parts of a dog's body, the prognosis tends to be good and dogs can be cured. However, a dog's condition would need to be closely monitored with frequent follow-up visits to the vet which ideally should be around every three months. The vet would take more thoracic X-rays to ensure a thymoma has not formed again and that dogs are responding well to a treatment.