Question:

I’ve been searching with success answering everything but my own question. Over the past few years, especially when I’m in a heavy allergy period or have done something to irritate my sinuses, a hard, round bump protrudes into the central/posterior of the left side of the hard palate, between .25 and .50 inches from the area where the hard and soft palate join. After a little over a week or so, the bump recedes. Any ideas?

Answer:

Maybe. Because this bump seems to be associated with inflammation of the nasal passages or sinuses, one thought would be that it represents part of the lymphoid tissue that encircles the back of the throat and roof of the mouth. A search term you may have seen is Waldeyer’s ring.

Most people are aware of the terms tonsils and adenoids to describe large segments of this tissue. Tonsils contain a number of white blood cells that make up a part of our immune system. When inflammation occurs around them, say with a bad sore throat, the cells may multiply and the tonsil gets bigger. After the sore throat improves, the tonsil (usually) shrinks back down.

On the roof of the mouth, many people have small clusters of lymphoid cells that look like very tiny tonsils under the microscope. These can grow bigger and shrink in response to inflammation the same way the regular tonsils do.
 
Your waxing and waning bump is probably one of these lymphoid aggregates that is responding to your sinus inflammation. As long as the bump does not persist or steadily enlarge, you probably have no reason to be concerned.
 
Otherwise, I would recommend you get the opinion of a dental specialist such as an oral pathologist or oral surgeon.

Good luck!

For more information:

Go to the Oral Cancer health topic.