Dermatologic Manifestations of Mucocele (Mucous Cyst) Workup

Updated: Mar 27, 2019
  • Author: Christopher R Shea, MD; Chief Editor: William D James, MD  more...
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Imaging Studies

Consider the additional studies described below to evaluate the anatomical extension of a deep mucocele (mucous cyst).

Plain radiographs show nonspecific soft-tissue density.

Ultrasonograms show a rounded or lobulated, hypoechoic mass with well-defined borders.

CT scans frequently demonstrate a circumscribed, water-density mass.

MRI shows a homogeneous, low-intensity lesion on T1-weighted images. T2-weighted images reveal an increased signal and sharp borders.


Other Tests

Fine-needle aspiration is commonly used in the evaluation of deep lesions. The aspirate smears usually show sparsely cellular mucoid material with a few histiocytes and inflammatory cells.


Histologic Findings

The specimens show collections of eosinophilic mucus admixed with some inflammatory cells in the upper portion or deep submucosa (see the image below). The mucus is periodic acid-Schiff (PAS) positive, diastase resistant, positive for colloidal iron and Alcian blue (pH 2.5), and hyaluronidase resistant. These properties of staining indicate a nonsulfated acid mucopolysaccharide, such as sialomucin. [17] The mucus has an epithelial rather than a fibroblastic origin.

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

Granulation tissue with an acute inflammatory infiltrate mainly forms the wall of the cystlike cavity (see the image below). [17] In time, the wall surrounding the cavity contains a variable number of fibrocytes and chronic inflammatory cells. An epithelial lining, most likely derived from the minor salivary ducts, is rarely identified in these biopsy specimens. The associated salivary gland is usually seen deeper in the connective tissue. This lesion may have lymphocytic infiltrates, ductal distention, degeneration of acini, and variable fibrosis.

The wall of the lesion is usually formed by connec The wall of the lesion is usually formed by connective tissue, inflammatory cells, foamy macrophages (lower left corner), and salivary gland acini (upper right corner).

Early in mucocele development, dilated lymphatics may be present at the periphery of the area where mucus is retained. [3]

Secondary changes (eg, parakeratosis, acanthosis, atrophy) may occur in the epidermis or squamous mucosa. Clear-cell change with signet-ring cell formation has been reported. [18] Transmucosal elimination of mucus has been reported. The superficial mucocele is a subepithelial blister. The roof of the lesion is formed by attenuated mucosa, while the floor consists of corium with sparse inflammatory infiltrates.

Some lesions appear to be intraepithelial blisters due to the regeneration of epithelium across the denuded base. The content of the lesion consists of variable amounts of eosinophilic mucus admixed with polymorphonuclear cells. Salivary gland ducts may open into the floor of the blister, and salivary gland lobules may be identified in deeper tissues.

Rare histologic variants of oral mucocele include those with features of myxoglobulosis (globular structures with intraluminal eosinophilic, lamellar, amorphous, or fibrillary material), papillary synovial metaplasia–like change, superficial mucocele presenting as a mucus-containing subepithelial blister, and a form exhibiting extensive clear cytoplasm and signet-ring alterations. [19]