In terms of age distribution, they appear at any age with a greater impact during the 20s and 30s and has equal distribution between the sexes. The predominant area of occurrence is the lower lip, especially around the canine teeth, the tongue and more rarely the upper lip.
Etiologically speaking, rupture of the excretory duct of a small salivary gland, as a result of injury, can lead to leakage and accumulation of saliva within the surrounding tissues. In this way a cavity is formed in the soft tissue that is not surrounded by an epithelial wall, being actually a pseudocyst called mucous extravasation cyst. According to another theory regarding the cysts’ development, the total or partial obstruction of a salivary duct may lead to the retention of saliva and the formation of a cavity containing saliva. These lesions are true cysts, because their wall is lined with epithelium and are called mucous retention cysts. Retention cysts are more common in adults and are found mainly on the floor of the mouth as well as in small salivary glands in the posterior third of the hard palate and in the adjacent soft palate, as a result of a mild, chronic, superficial irritation.
Mucous cysts, regardless of their etiology, appear as soft, asymptomatic swellings with a color ranging from deep blue to normal pink. The color depends mainly on the depth of their localization with the superficial lesions having a clear blue color and the appearance of a fluid-filled vesicle, while in deeper layers they retain the color of the normal mucosa.
Mucous cysts are surgically removed along with the symptomatic salivary gland. At the same time it is advisable to remove the adjacent salivary glands to eliminate the possibility of recurrence. Planning details are important before surgery, especially in the case of the lower lip, in order to achieve a good aesthetic result. The wound is sutured and appropriate postoperative instructions are given in order to achieve the best possible result. The frequency of relapses, according to studies, ranges between 9-18%, most likely as a result of incorrect and/or incomplete surgical manipulations.