The mucus escape reaction describes a leakage of mucus from a salivary gland into the submucosa, resulting in a clinical nodule. In many cases there is severance of a duct with release of the mucus into adjacent soft tissues.


Synonyms: mucocele, mucus retention cyst, ranula (for lesion in the floor of the mouth beneath the tongue)


Clinical features:

(1) The reaction occur more frequently with minor salivary glands, but also may occur with a major salivary gland.

(2) The patient has a nodular lesion along the oral buccal mucosa, especially the lower lip or floor of the mouth.

(3) Larger lesions are fluctuant on palpation.

(4) The typical appearance is a translucent bluish-gray, but it may be reddish if there is hemorrhage secondary to trauma.


Histologic features:

(1) pooling of mucus in the submucosa or connective tissue

(2) absence of an epithelial cell lining

(3) patchy subacute inflammation with foamy macrophages

(4) lesions resolve by increasing fibrosis

(5) adjacent salivary glands may show pooling of mucus, acinar atrophy and fibrosis


Differential diagnosis:

(1) mucus retention cyst (cyst with an epithelial cell lining)

(2) hematoma

(3) hemangioma or lymphangioma

(4) salivary gland tumors

(5) developmental cysts


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