CYSTS OF ORAL CAVITY

INTRODUCTION

Fluid filled epithelial lined pathological cavity

regardless of origin, once cysts develop in oral and maxillofacial

region it tends to slowly increase in size

It may happen so, possibly in response to a slightly elevated

hydrostatic luminal pressure .

Depending upon the tissue of origin it could be either

Odontogenic Cyst

Non – odontogenic Cyst

RADICULAR CYST

A true cyst & most commonly occurring cyst of the oral cavity

52% to 68% of all the cysts affecting the human jaws

Their prevalence is highest among patients in their third decade of life, and

higher among men than women

seen in association with non vital tooth.

Pathogenesis

Develops due to inflammatory response in the periapical tissue .

Inflammation resorption of bone formation of granulation

tissue acute and chronic inflammatory cell infiltration.

Epithelial lining of the cyst derived from the cell of Rest of Malassez

Histologically it is squamous epithelial lined cystic lumen surrounded by

inflammed fibrous connective tissue.

Most of them are asymptomatic and discovered on routine radiographs.

Patient often complains of slowly enlarging swellings.

At first the enlargement is bony hard but as the cyst increases in size, the covering

one becomes very thin despite subperiosteal bone deposition and the swelling then

exhibits 'springiness‘

when the cyst has completely eroded the bone, there will be fluctuation

Patient may also complains of pain when the cyst get infected

RADIOGRAPHIC FINDINGS Well defined radiolucency at the periapical region or sometimes lateral to the

root.

The cysts may displace adjacent teeth or cause mild root resorption.

Radiographically, it is indistinguishable from periapical granuloma.

But it has been observed that if the lesion larger than 2 cm is more likely to be a

cyst

Treatment

Endodontic therapy

Apicectomy

Extraction and curettage of the periapical tissue

RESIDUAL CYST

When the offending tooth is removed but the radicular cyst was

left behind completely in the socket

Radiographically appear as well defined radiolucency at the site of

previously extracted teeth.

Conservative surgical excision is the treatment of choice

DENTIGEROUS CYST

A dentigerous cyst encloses a crown of an unerupted tooth by its

follicle and is attached to the neck of the tooth.

They may be of developmental or inflammatory origin.

Dentigerous cyst is the most common developmental odontogenic

cyst.

Other developmental cysts of oral cavity are odontogenic

keratocyst, primordial cyst, Gorlin cyst, lateral periodontal cyst,

eruption cyst, and gingival cyst,

ETIOPATHOGENESIS Still poorly understood

It seems to develop due to alteration of reduced enamel epithelium

after completion of amelogenesis.

Fluid accumulation between the epithelium and tooth crown

The cause of this alteration could be inflammatory or some

unknown reason.

Non vital tooth Inflammation Dental follicle

Development of cyst

Development of radicular cyst in non vital primary tooth

Permanent tooth erupt through the radicular cyst

Development of dentigerous cyst of extrafollicular origin

Diagnosed in the first and early part of second decade.

If asymptomatic than on routine radiographic examination or

Sometimes patient may complains of swelling and pain.

.

In order of decreasing frequency, dentigerous cyst associated with

Mandibular third molars,

Maxillary canines,

Mandibular second premolars,

Maxillary third molars,

Mandibular first premolar,

Maxillary second premolar

and Mandibular canine.

Radiographically, there are three variants of dentigerous cysts.

Central,

Lateral and

Circumferential

These variants invariably demonstrate a unilocular radiolucency with sclerotic

borders surrounding the crown of the tooth

A large dentigerous cyst may appear multilocular radiographically due to the

persistence of bone trabeculae within the radiolucency.

Have potential attend large with root resorption of the adjacent tooth

Chances of neoplastic changes and development of carcinoma

Differential Diagnosis

Radicular Cyst

Ameloblastoma

Adenmatoid odontogenic tumour

OKC

Treatment

Wide excision of the lesion and removal of associated teeth

Histopatholpogical examination to exclude neoplastic changes

ERUPTION CYST /HEMATOMA

Soft tissue analog of dentigerous cyst with no bony involvement

appears as a soft, translucent, dome shaped bluish gray swelling

filled with blood or a clear fluid overlying the crown of an

erupting tooth.

Most common teeth involved are permanent molars and maxillary

incisors.

Treatment

Excision of the wedge of mucosa to expose the crown

KERATOCYSTIC ODONTOGENIC TUMOR

The first description of OKC was published by Philipsen in 1956 for all the

cysts that showed keratinization histologically

In 1992, WHO reported that OKC was the preferred terminology for cysts with

keratinized lining.

It is believed to arise from cell rests of the dental lamina

In 2005 WHO has reclassified OKC as Keratocystic odontogenic tumor and

defined it

“a benign uni- or multicystic intraosseous tumor of odontogenic origin, with a

characteristic lining of parakeratinized stratified squamous epithelium and

potentially aggressive, infiltrative behavior.

.

Reasons to reclassify it as tumor

Aggressive clinical course

Tendency for recurrence

Its association with certain genetic abnormality

Its association with Nevoid Basal Cell Carcinoma

It has unique histological feature

Lumen lined by 8-10 cell thick epithelium and surfaced by

parakeratin

CLINICAL FEATURE

Most common in posterior mandible region. But it may be present

at any site of maxilla and mandible

But cyst present in mandible has more chance of recurrence

May present as painless swelling.

Displacement of adjacent teeth may be present

Pain due to secondary infection may be present in some cases

RADIOGRAPHIC FEATURES

Radiographically it may be present as a small unilocular radiolucency or larger

lesion may be multilocular pattern with distinctly corticated, often scalloped,

borders.

Minimal expansion, especially toward the lingual (medial) side and growth

along the length of the mandible.

A radiolucent lumen is seen which can have a hazy appearance in conventional

radiography. This hazy appearance or high attenuation is suggestive of a dense

proteinaceous material such as keratin.

Displacement of developing teeth and/or separation or rarely resorption of the

roots of erupted teeth and extrusion of erupted teeth

DIFFERENTIAL DIAGNOSIS

Must be differentiated from

Dentigerous cysts,

Ameloblastomas,

Radicular cysts,

Simple bone cysts, and

Central giant cell granulomas

NEVOID BASAL CELL CARCINOMA Inherited as autosomal dominate trait with high penetration rate

Associated with mutation of PCTH1 gene

Development of basal cell carcinoma at early age on non –sun exposed skin.

Multiple OKC

Mild hypertelorism

Enlarged calvarium

Calcification of falx cerebri

Rib abnomalities

Pitting of sole and palms

Treatment of OKC

Simple curettage/marsupilzation

IMAGES OF OKC

LATRERAL PERIODONTAL CYST Its named so because of its location.

It has a distinct and characteristic histological features.

Histologically characterized by thin lining of stratified squamous epithelium

with focal epithelial thickening.

Present as unilocular radiolucency on lateral aspect of vital mandibular cuspid

or premolar tooth.

May cause displacement of adjacent teeth

The multilocular variant is known as Botryoid Odontogenic Cyst.

Must be treated with conservative surgical excision

IMAGES OF LATERAL PERIODONTAL CYST

CALCIFYING ODOTONOGENIC CYST

It was categorized as a single entity by Gorlin et al. in 1960

It is a rare developmental odontogenic cyst.

Non aggressive cystic lesion lined by odontogenic epithelium that

resembles ameloblastoma but with characteristic ghost cell keratinization

and calcification.

There is no consensus regarding the classification and terminology of

COC.

This benign lesion is categorized as either a cyst or neoplasm.

.

In the cystic variant, three different types may be found:

Simple unicystic type,

Unicystic odontoma-associated type

Unicystic ameloblastomatous proliferating type

According to Shear it accounts for about 1% of all odontogenic cyst and

represents about <6% of all odontogenic lesions.

it may develop at any age from the second to the eighth decade of life

either in the mandible or in the maxilla,

Most common site of occurrence is between incisors and canines.

RADIOGRAPHIC FEATURE

Radiographically, the lesion appears as a unilocular or multilocular well-

defined radiolucency

It may contain small irregular calcified bodies of varying sizes

It may be associated with an odontoma or an unerupted tooth

It has been noted in association with impacted teeth in about 10--32% of the

cases.

Displacement of teeth and resorption of the roots of the adjacent teeth are

frequent findings

NEOPLASTIC VARIANT/CALCIFYING CYSTIC

ODONTOGENIC TUMOR

A rare, locally invasive, epithelial odontogenic neoplasm characterized by the presence

of amyloid material that may become calcified and known as Pindborg tumor)

It account for less than 1% of odontogenic tumors

Mandible > maxilla (2 : 1), specifically premolar/molar region

There is equal sex distribution with most common age group is between 20 and 60 year

It present as slowly enlarging painless mass of the jaw

Radiographic Features

Well-circumscribed unilocular or multilocular radiolucencies with variable opaque

flecks. Calcifications described as “driven snow” or “plowed snow”

Up to 60% associated with crown of unerupted tooth

IMAGES OF COC

PINDBORG TUMOR

GLANDULAR ODONTOGENIC CYST

It is a developmental cyst of jaw that histologically resembles the botryoid

odontogenic cyst.

It is a cyst with an unpredictable, potentially aggressive behavior, and has the

propensity to grow in large size with relatively high recurrence rate.

Affects middle aged individual with no sex predilection.

Anterior mandible is the most commonly affected site

Patient is either asymptomatic or complains of painless swelling of the jaw.

MAJOR AND MINOR HSITOPATHOLOGICAL

CRITERIA FOR DIAGNOSIS (Kalpan et al)

Major Criteria Squamous epithelial lining with a flat interface with the connective

tissue wall , lacking basal palisading

Epithelium showing variation in thickness along the cystic lining with or without epithelial spheres or whorls or focal luminal proliferation.

Cuboidal eosinophillic cells.

Mucous cell with intraepithelial mucous pools with or without crypts lined by mucous producing cells.

Intraepithelial glandular, micro cystic or duct like structure

Minor Criteria Papillary projection of the lining epithelium

Ciliated cells

Multicystic architecture

Clear cells in basal or spinous layer

Radiographic Features

It may present as unilocular or multilocular pattern.

They have well defined borders, which may be sclerotic .

Scalloped pattern is also present in some cases.

Incase of large lesion perforation of the jaw margin may also be present

(aggressive pattern)

Association of this cyst with unerupted teeth is very unlikely.

Displacement of teeth and root resorptions are also present

Differential diagnosis

Botryoid Cysts,

Central mucoepidermoid carcinoma (CMEC)

Ameloblastoma.

Keratocysts,

Residual cysts

BUCCAL BIFURCATION CYST Buccal bifurcation cyst (BBC) is an uncommon inflammatory odontogenic cyst

of pediatric age group.

It was first reported in 1983 by Stoneman and Worth.

Exact etiology is not known but the tooth breaks the oral mucosa during

eruption, thereby causing inflammation and activating the proliferation of

epithelial cells, which ultimately forms a cyst.

It is also speculated that the tilted mesiobuccal cusp and deep periodontal

pockets may be the origin of the inflammation

Other local predisposing factors include enamel projections from the cemento-

enamel junction into the furcation and covered by reduced enamel epithelium

that lead to cyst formation

Clinical features

Most common age of occurrence is in children between 4 and 14 years

and predominantly affects the mandibular first molar.

Occasionally, the mandibular second molar may be the involved tooth.

Delayed tooth eruption and swelling at the affected area is commonly

observed.

In some cases, partial tooth eruption with crown buccal tilting and deep

periodontal pockets may be present.

It is often asymptomatic but in case of infection drainage of pus, and

pain can be present

RADIOGRAPHIC FEATURES OF THE BUCCAL BIFURCATION CYST

Fine radiopaque concave line as lower limit, producing a U-shaped radiolucent

lesion that appears superimposed over the roots.

Intact periodontal ligament space and lamina dura.

Increased prominence of lingual cusps due to tilting.

Apices tilted toward lingual cortex.

Differential Diagnosis

Dentigerous cyst

Paradental cyst

NON ODONTOGENIC CYST Nasopalatine canal cyst

The nasopalatine cyst also known as incisive canal cyst is the most common

epithelial and non odontogenic cyst of the maxilla.

The cyst originates from epithelial remnants from the nasopalatine duct.

Although aetiology of this lesion is still uncertain, the NPDC most likely

represents a spontaneous cystic degeneration of remnants of the nasopalatine

duct

There may be some genetic factor that may play role.

Clinical Features

Develop in the midline of anterior maxilla near the incisive foramen.

Most common age of occurrence is between 4th to 6th decades of life.

More common in males than females.

Usually asymptomatic and diagnosed on routine radiographs.

Sometimes it becomes symptomatic due to secondary infection and

present clinically as swelling, drainage and pain.

Radiographic Features The periphery of the cyst is well-defined and corticated. It is circular or oval in

shape.

The shadow of the nasal spine sometimes is superimposed on the cyst, giving it

a heart shape.

Diversion of root of central incisors with occasional root resorption may be

present.

Differential Diagnosis

Large incisive foramen.

Radicular cyst

Primordal cyst arising from mesiodense

Treatment

Surgical excision and enucleation

NASOALVEOLAR CYST

Uncertain pathogenesis with no alveolar bone.

Seen in older individual with female predeliction(4:1).

They generally present as facial swellings or asymmetry like elevation of the ala

of the nose, inferior turbinate or upper lip, with obliteration of the nasolabial

fold.

Generally painless and are undetected by routine dental radiography because

they are present entirely in the soft tissues.

Contrast enhanced CT image provide better image.

DIFFERENTIAL DIAGNOSIS ▸ Periapical cyst

▸ Lipoma

▸ Salivary gland neoplasm

▸ Epidermoid cyst

Treatment

Complete enucleation is usually curative

SIMPLE BONE CYST/HEMORRHAGIC BONE CYST The traumatic bone cyst (TBC) is an uncommon nonepithelial lined cavity of

the jaws.

The lesion is mainly diagnosed in young patients most frequently during the

second decade of life.

The majority of TBCs are located in the mandibular body between the canine

and the third molar.

Clinically, the lesion is asymptomatic in the majority of cases

It is often accidentally discovered on routine radiological examination usually

as an unilocular radiolucent area with scalloping margin around the roots of the

teeth.

Surgical intervention reveals void within the bone