A. Thymoma is in fact a tumor of the thyroid gland. If surgery isn't an option then radiation is the most commonly pursued therapy. However, it is also being successfully treated in many cases with chemotherapy. If no treatment is pursued then the most common sequela is megaesophagus - the esophagus dilates to the point that food can't be swallowed and aspiration pneumonia occurs frequently. I can't tell you the exact amount of time they typically live, but usually dogs with chronic megaesophagus are euthanized in less than a year due to the recurrent pneumonia.
It's also worth mentioning that many dogs with thymoma also have a disease called myasthenia gravis, and this should be considered in your dog's case.
A. This question is a bit confusing. I think you may mean thyroid but I do not understand why it would need to be removed. Most thyroid diseases can be managed with oral medication and do not always require surgery. I cannot answer how long your dog will live because I do not have enough information about his condition or disease.
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