My teenage daughter has a large "bubble" on the inside of her lower lip. It looks like it is full of fluid, in that it is translucent, but it is actually solid. She has had it about a week and it grows and shrinks in size. She would like to know what it is and how to get rid of it.

Art

This is most likely a mucus-retention cyst. Obviously, the only way to know for certain is for your daughter to be evaluated by an ear, nose and throat doctor (ENT) and for the mass to be biopsied.

Scattered throughout the mucus membranes of the nose, mouth and throat are thousands of "minor salivary glands." Think of these things as tiny saliva factories that transmit their "product" through even tinier straw-like conduits (called ducts), dumping their contents into the mouth, throat or nasal cavities.

If a duct becomes obstructed, saliva can dilate it. Think of a water balloon and you won't be too far off, except that this is not water. There is a great deal of protein in saliva, so, don't be too surprised if a cyst feels firmer than you would expect from a water balloon.

Here's another possibility: like any body tissue, the minor salivary glands can give rise to tumors. If it is a solid tumor, this would account for the bubble's oddly firm texture. My hunch is that this mass is not a tumor, because of your observation that it "grows and shrinks in size." Tumors don't often do this.

As I stated above, your daughter would be best served by having this critter removed by an ENT. If she is a mature teenager, she should be able to tolerate having it removed under local anesthesia in the doctor's office. This is not a terribly painful operation; the worst part is getting the injection of local anesthetic. There is a small risk of bleeding, infection and recurrence of the cyst. If the bubble is, in fact, a tumor, then further surgery might be necessary to thoroughly eradicate it.

As with any mysterious lump, one also has the options of biopsy with a needle or simply "observing" the lump. If you choose observation, you would agree to visit the doctor on a regular basis, returning to the doctor sooner should the lump change significantly. Your daughter's ENT would be the best person to advise you as to the relative merits of these options.