Mucocele or mucous retention cyst is dilatation of minor salivary glands secondary to an duct obstruction or trauma. Mucus secretion accumulates in the gland, and the eventual rupture leads to extravasation of mucus into surrounding connective tissue. Shown here is a mucocele in the upper lip. It is a mobile, smooth and soft lesion measuring 1.5 to 2cm.
Part of the cyst is seen with the cavity partially filled with polymorphonuclear cells and eosinophils. Many mucous glands are seen below the cystic cavity.
This is an example of a traumatized minor salivary gland duct with a cystic space lined by histiocytes and filled with extravasated mucin material. The best term to use is “mucous extravasation phenomena”. There is no ductal epithelium surrounding the extravasation. The clinical diagnosis would be “mucocele” with an adjacent focus of minor salivary gland.
Mucocele is relatively rare lesion that occurs in all age groups. Trauma of minor salivary glands and subsequent extravasation of mucus into surrounding connective tissue results in the formation of mucocele. Patients present with mobile, soft to firm vesicle or nodule on either the upper or lower lip, associated with pain or discomfort. The lesion can occur in other areas such as the floor of mouth, tongue, palate, and buccal mucosa. Treatment involves surgical resection of the mucocele. Recurrences are rare.