Cysts under the tongue may be either mucous cysts of the tongue abdomen or cysts of the sublingual gland. One of the main reasons for their formation is the formation of retention cysts due to partial obstruction and dilatation of the distal portion of the ducts; the other is the formation of extravasation cysts due to breakage of the ducts or glands and exudation of mucus to the outside. 1. Mucus cysts in the tongue and abdomen: the formation of retention cysts with epithelial lining is mostly due to the obstruction or dilatation of the duct by biting through the duct. The cysts are soft and clear, with light blue vesicles. Egg-white transparent mucus liquid can be discharged when the cyst is punctured. 2. Sublingual gland cysts: most common in adolescents, can be formed due to duct obstruction and epithelial lining of retention cysts; can also be due to gland or duct breakage, mucus flow to the tissue interstitial space to form epithelial-lined exudative cysts. If you find a cyst under your tongue, you should consult a doctor in time, complete the examination, clarify the cause and diagnosis, and standardize the treatment under the guidance of a professional physician.