Thought by many to be a rumor too gross and weird to be true, sialoliths - stones that form in your salivary ducts (I guess that makes them spit stones?) - are quite real indeed, and happen more frequently than you would imagine. They are up on Wikipedia, so they must be real, right?
These curious stones, or sialoliths as they are called, usually occur in the submandibular salivary ducts, which produce nearly two thirds of the saliva in humans, and this gland is also home to the largest saliva producing duct in our species, the Wharton’s duct. These little stones can block this duct, which is a nasty experience altogether. This causes dryness of the mouth and of the mucus membrane, and the duct will get infected, which translates into swelling of the face and sometimes tongue, and a milky white, foul tasting discharge coming from the duct directly into the mouth. Yuck.
Sialoliths, once they occur, must be removed with a relatively routine surgery. If the sialolith is not removed for a long enough time, the gland can get so infected that it has to be removed altogether, which is also the case if the gland repeatedly causes stones to appear, which will necessarily cause complications throughout the rest of the patient’s life. Indeed, the endocrine system is a harsh mistress.
These stones can be as small as a grain of sand to around the size of a larger bean.
Thankfully, the little buggers can be spotted on an x-ray, or, at least 80% of the time they can be, so they can usually be removed before the oozy discharge parts comes into play. If the stone is spotted, it does not always end in oral surgery. If the stone is still small, a special massage can cause the salivary gland to actually expel the stone on its own, stretching to the right size from the massage. Patients are usually told to eat acidic or vinegary foods, especially citrus foods, since those are good for you, taste great, and create an increase in salivation, which just may break the stone up. Otherwise, the duct needs to be surgically enlarged, and the stone pushed out by the body through the larger opening. It may also be the case that the stone is too large for that, in which case a small incision is made near the gland, and the stone is removed forcibly through that opening. Only in extreme situations is the gland removed.
The funny thing is, no one seems to know what causes these stones to appear. They are made up of the same substance as kidney stones (hydroxylapatite), which is basically a deposit of calculus, calcium and phosphorus. So we know what its made of, how it reacts, what it does and how to remove it, but we have not the faintest idea how it gets to be concentrated and why, and especially why in the Wharton’s duct. Therefore prevention is all but impossible and it’s down to the luck of the draw.