Dermatologic Manifestations of Mucous Cyst

Updated: Jun 06, 2016
  • Author: Christopher R Shea, MD; Chief Editor: William D James, MD  more...
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Overview

Background

A mucous cyst is a benign, common, mucus-containing cystic lesion of the minor salivary glands in the oral cavity (see the image below). Some authors prefer the term mucocele since most of these lesions are not true cysts in the absence of an epithelial lining. The lesions can be located directly under the mucosa (superficial mucous cyst), in the upper submucosa (classic mucous cyst), or in the lower corium (deep mucous cyst). Two types of mucous cysts occur based on the histologic features of the cyst wall: a mucous extravasation cyst formed by mucous pools surrounded by granulation tissue (92%), and a mucous retention cyst with an epithelial lining (8%). [1]

The submucosa shows a mucin-filled, cystlike cavit The submucosa shows a mucin-filled, cystlike cavity below the squamous mucosa. Minor salivary gland lobules are present in the submucosa.
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Pathophysiology

The mechanism of mucous cyst formation is unclear; however, a traumatic etiology rather than an obstructive phenomenon is considered more likely. Chaudhry et al showed that the escape of mucus into the surrounding tissue after severing the excretory salivary ducts led to mucous cyst formation. [2] The frequent location of the mucous cyst in the lateral aspect of the lower lip also supports the role of trauma as an etiologic factor. Although obstruction may play a role in the etiology of the mucous cyst, Chaudhry et al demonstrated that ligation and cutting of the salivary glands' ducts in rodents did not result in mucous cyst formation. [2] Lymphatic vessels may also contribute to the early stages of mucous cyst development. Specifically, the growing mucous cyst may induce a pressure gradient that causes lymphatics to swell with interstitial fluid, eventually rupturing and delivering this fluid back to the mucous cyst. [3]

In a study of 138 pediatric cases, Martins-Filho et al concluded that trauma is the main etiologic factor involved in the development of mucoceles in children. The mucus extravasation phenomenon is the most common histologic type in this age group. Although rare, the retention type seems to be more common in lesions on the floor of the mouth. [4]

After reviewing 1,824 adults, Chi et al confirmed previous findings concerning the clinicopathologic features of oral mucoceles. Although special variants do occur infrequently, they need to be identified to avoid misdiagnosis. [5]

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Epidemiology

Frequency

The prevalence of oral mucous cyst is 2.5 lesions per 1000 population. [6]

Race

Mucous cysts are most frequent in whites.

Sex

The incidence of mucous cyst is about equal in males and females. [7]

Age

Although patients of all ages can be affected, more than half of mucous cyst cases occur in those younger than 30 years. In a large oral pathology series in children and adolescents, mucocele was the most common entity diagnosed (33% of cases), and the lip mucosa was the site most often involved (48%). [8] However, mucocele is uncommon in neonates and infants. [9] Very rarely, congenital onset has been reported. [10]

Mucous retention cysts are more frequent in older persons; conversely, the majority of mucous cysts in younger patients represent the extravasation type. [11]

Mucous cysts of the glands of Blandin-Nuhn (present on the ventral surface of the tongue) appear to be more prominent in young patients. [11]

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Prognosis

Mucous cyst, a benign condition, is self-limited in most cases. Patients with mucous cysts have an excellent prognosis; however, recurrence is common in the absence of resection of the associated salivary gland.

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