Cysts of the jaws

Definition:

A cyst is a pathological cavity with fluid, semi-fluid or gaseous contents, which is not created by accumulation of pus. It is frequently lined by epithelium.

Typical features of jaw cysts

Most jaw cysts behave similarly—they grow slowly and expansively. They differ mainly in relationship to teeth and radiographic features. They form sharply-defined radiolucencies with smooth borders and are frequently a chance radiographic finding.

Clinical Features

Noticeable swelling: initally smooth bony hard lump with normal overlying mucosa, but as bone thins through resorption, cyst may show through as bluish fluctuant swelling (compressible)

Discharge into mouth

Pain due to secondary infection

Fluid may be aspirated and thin-walled cysts may be transilluminated

 

Classification of cysts of the jaws

Odontogenic cysts

¨ Developmental

                          -Gingival cyst of infants (arise from remnants of dental lamina)

                          -Dentigerous (follicular) cyst (arise in bone around crown of unerupted tooth)

                          -Eruption cyst (often burst spontaneously, rarely require excision)

-Odontogenic keratocyst (see radiograph on left, arise from dental lamina, multilocular, 60% recur, Gorlin-Goltz syndrome)

                          -Gingival cyst of adults (arise from epithelial rests in gingivae)

 

¨ Inflammatory (55% of all cysts – epithelial rests of Malassez)

Radicular cyst (= apex of non-vital tooth, see radiograph on right)

Lateral Periodontal cyst (= lateral aspect of vital tooth)

Residual cyst (cyst remains following removal of non-vital tooth)

¨ Neoplastic

-Ameloblastoma (locally malignant, often multilocular, excision with wide margin of normal tissue, see radiograph below)

                          -Calcifying epithelial odontogenic (Pindborg, mixed radiolucency, locally invasive)

 

 

 

 

 

Non-odontogenic cysts

Nasopalatine duct (incisive canal) cyst (Care not to confuse with anterior palatine fossa on x-ray, see picture on right)

Nasolabial cyst (nasolabial fold swelling – distorts nostril)

Median palatine, median mandibular cysts

 

Cysts without epithelial lining

-Solitary (simple) bone cyst (arches up between roots of teeth, Rx.=allow bleeding into cavity)

-Aneurysmal bone cyst (multilocular, 10-20yrs, very expansile, blood-filled spaces, giant cells)

 

Diagnostic tests

¨ Radiographs—intra and extra-oral views

¨ Vitality testing of associated teeth

¨ Aspiration and analysis of fluid contents

¨ Straw-coloured fluid containing cholesterol crystal from most Radicular cysts

¨ Air, some blood or serosanguious fluid from Solitary Bone cysts

¨ Blood from Aneurysmal Bone cyst

¨ Pus from infected cyst

¨ Pale, yellow fluid containing keratin from Odontogenic Keratocyst

¨ Biopsy of lining, provides definitive diagnosis

 

Management

1. Enucleation with primary closure is most common, and generally the treatment of choice. It consists of removing the cyst lining from the bony walls of the cavity and repositioning the access flap. Any relevant dental pathology is treated at the same time.

2. Enucleation with packing and delayed closure is used when badly infected cysts, particularly very large ones, are unsuitable for primary closure. Pack with Whitehead’s varnish.

3. Enucleation with primary bone grafting

4. Marsupialization—opening of the cyst to allow continuity with the oral mucosa. Healing is slower than with enucleation and a cavity persists for some time.

 

Always submit the whole specimen for histopathology

Cysts are usually painless when small and can cause significant bone loss before presenting clinically. Cysts arising from odontogenic origin (odontogenic epithelium) account for most cysts of the jaws.