A reader called to say that he had a blister in his mouth, the size of a green pea, but it didn’t hurt. Sometimes, he bit through it himself and blood and pus would come out. But after a while, it would grow again. In this way, it went back and forth for about a year. A friend who knows something about medicine said that the ulcer is quite scary if it does not hurt, and it may be oral cancer. After that, he went to the hospital and the doctor said it was a cyst and suggested to cut it out. But he doubted that such a small herpes would require surgery? The situation this reader responded to is still relatively common, and the diagnosis is relatively easy. According to the professional terminology, or its scientific name, it should be called a small salivary gland mucous cyst. As the name implies, it is a small sac that swells up on the lips, tongue or the floor of the mouth. As we know, besides the familiar parotid, submandibular and sublingual glands, there are many small salivary glands that secrete saliva in the lips, buccal mucosa, tongue or floor of the mouth, which are located under the thin mucous membrane and have a small duct to secrete saliva into the mouth, the amount is so small and silent that it is usually not felt. For some reason, the duct is broken or blocked, the saliva secreted by the small gland cannot be secreted normally into the mouth, and it is gathered in place into a small bubble, usually the size of a green bean to peanut rice, soft and somewhat elastic, translucent, not painful. The best part of the mucous cyst is the lower lip and the tip of the tongue, because the movement of the tongue is often injured by the friction of the lower front teeth and the conscious or unconscious action of biting the lower lip, which causes the submucosal glands to develop. Mucous cysts sometimes break on their own, some friends will bite a bite from time to time, also will bite broken, broken out of a packet of mucus, mixed with a little blood, the packet is gone, it seems that everything is fine. However, after a few days, the bag appeared there again. After several repetitions, it does not have the characteristics mentioned above, but becomes a thick white bump, much harder than it started. It is still not the same as an ulcer, first of all, the look is different. Mucus cysts are round and fat, while ulcers are mucous membrane ulcers with a yellowish-white surface and red periphery. Secondly, mucus cysts are generally painless, while ulcers are more painful, especially the multiple ones, and those who suffer from them have the impression that it is difficult to even eat. Finally, although both seem to disappear on their own, they are actually completely different. The ulcer is truly healed, clinically called self-healing, (clinically dreadful ulcers are ulcers that do not heal themselves, and bulging ulcers that do not heal for more than a month, and ulcers that are hard and hard around them must be taken seriously). The next reappearance is a new one, usually with a change in location, while the “disappearance” of the cyst is just the absence of the packet, which reappears in the same location within a few days, a continuation of the same lesion. In addition to these common small salivary gland mucous cysts, there is another type of salivary gland cyst commonly found in adolescents, the sublingual cyst. The most typical sublingual cyst is located at the floor of the mouth (under the tongue) and it is a cyst that occurs in the sublingual gland for the same reason, a ruptured or blocked duct. However, sublingual cysts are much larger and can sometimes extend to the opposite side, lifting the tongue. They are soft to the touch, and like small salivary gland cysts, they break down and bleed more egg-white mucus, and after a few days, the wound heals and the cyst grows again. The treatment of small salivary gland mucous cysts is currently mostly surgical, because the cysts are located under the mucosa, above the muscle layer, relatively superficial, surgery is not difficult and risky. As long as the patient can cooperate, it can usually be done on an outpatient basis. In the case of some patients who cannot physically tolerate surgery, or who strongly reject it, a more conservative treatment can be considered, mainly by injecting 2% tincture of iodine, usually 0.2-0.5 ml, into the cyst after the cyst fluid has been extracted, staying for about 3 minutes, and then extracting the tincture of iodine. Its main purpose is to destroy the salivary gland cells that no longer secrete saliva to form cysts, but in the case of those that break down repeatedly, surgery is the only way to go. For sublingual cysts, the radical cure is to remove the sublingual gland. This surgery is not very difficult, but after all, it is an organ removal that involves some nerves and blood vessels at the floor of the mouth, and patients are usually advised to be hospitalized. For patients whose general condition is not too good and cannot tolerate the surgery, a simple pouch suture can be done, which simply means that only the mucosa and the wall covering the cyst are removed to prevent the saliva from gathering again to form a cyst, and then the sublingual gland is removed when the patient’s general condition improves or when the child grows up. Nowadays, with the promotion of functional surgery, pocket suturing to maintain the sublingual gland is becoming an option, but its long-term results need to be further observed and studied. Just like the upper teeth inevitably touching the lower teeth, the lips are inevitably bitten, plus the cause of those tiny stones formation is also unclear, so there is basically no way to prevent it. The good thing is that it is not very harmful and the treatment is quite simple, so it is good to find a convenient time to do a small surgery after a clear diagnosis.