Cystofjaw rkv

1

Good Afternoon....

2

Cysts Of The Oral AndMaxillofacial Region

Presented by,Dr Ravikumar V,Dept Of Oral Pathology,Govt Dental College,Kottyam

Brushing up…

• Definition• True cysts and pseudocysts

CLASSIFICATION

I. Cysts of the jaws

1. Developmental Origin• (a) Odontogenic

i. Gingival cyst of infantsii. Odontogenic keratocystiii. Dentigerous cystiv. Eruption cystv. Gingival cyst of adultsvi. Developmental lateral periodontal

cystvii. Botryoid odontogenic cystviii. Glandular odontogenic cystix. Calcifying odontogenic cyst

• b) Non-odontogenic

i. Midpalatal raphé cyst of infantsii. Nasopalatine duct cystiii. Nasolabial cyst

A. EPITHELIAL-LINED CYSTS

I. Cysts of the jaws

2 .INFLAMMATORY ORIGINi. Radicular cyst, apical and lateralii. Residual cystiii. Paradental cyst and juvenile paradental cystiv. Inflammatory collateral cyst

• B. NON-EPITHELIAL-LINED CYSTS1. Solitary bone cyst2. Aneurysmal bone cyst

II. Cysts of the soft tissues of the mouth, face and neck

1. Dermoid and epidermoid cysts2. Lymphoepithelial (branchial) cyst3. Thyroglossal duct cyst4. Anterior median lingual cyst (intralingual cyst of foregut origin)5. Oral cysts with gastric or intestinal epithelium (oral alimentary tract cyst)6. Cystic hygroma7. Nasopharyngeal cyst8. Thymic cyst9. Cysts of the salivary glands: mucous extravasation cyst; mucous retention

cyst; ranula; polycystic (dysgenetic) disease of the parotid10.Parasitic cysts: hydatid cyst; Cysticercus cellulosae; trichinosis

PATHOGENESIS

• TWO STAGES

1. Cyst initiation2. Cyst enlargement or

expansion

a. Initiation b. Formationc. Enlargement

CYST INITIATION

• Initiation results in the proliferation of the epithelial cells and the formation of small cavity.

• a. Cell Rests of Malassez : Remanants of Hertwigs epithelial root sheath in the PDL after the root formation is completed.

• b. Reduced Enamel Epithelium : Residual epithelial cells surrounds the crown of the tooth after enamel formation is complete.

• c. Cell Rests of Serres (Dental Lamina) : Islands of epithelial cells that originate from the oral epithelium and remain in the tissue after inducing tooth development.

11

a

b

c

Frequency of Epithelial Cysts of Jaws

52.30%

18.10%

11.60%

8.00%

5.60%

4.20% SHEAR 2006Radicular cyst

Dentigerous cyst

Odontogenic keratocyst

Residual cyst

Paradental cyst

Unclassified odontogenic cysts

DENTIGEROUS CYST

• The dentigerous cyst is defined as a cyst that originatesby the separation of the follicle from around the crownof an unerupted tooth

• The dentigerous cyst encloses the crown of an unerupted tooth and is attached to the tooth at the cementoenamel junction

• It develops by accumulation of fluid between the reduced enamel epithelium and the tooth crown.

Dentigerous cystGross specimen of a dentigerous cyst. Cyst encloses the crown of the tooth and is attached to its neck

CLINICAL FEATURES

• AGE : 1st to 3rd decades.• GENDER : more frequently in males than in females.• SITE : • 2/3rd associated with unerupted mandibular 3rd molar• Maxillary canine• Mandibular premolar• Maxillary 3rd Molar• Supernumerary tooth also can be involved

Signs & symptoms

• Most cysts grow to a large size before being discovered accidentally while observing a dental x ray to detect the cause of an unerupted tooth.

• Large lesions can cause cortical expansion, leading to facial asymmetry, teeth displacement, root resorption, even pain, if infected.

RADIOLOGICAL FEATURES

• Manifests as unilocular, well defined, ‘lucency with sclerotic margins, associated with crown of impacted / unerupted tooth.

• A large DC may show persistence of boney trabeculae, giving the appearance of multilocularity.

RADIOLOGICAL FEATURES

• CENTRAL TYPE:

• LATERAL TYPE :

• CIRCUMFERENTIAL TYPE :

Radiographic features

A central type of dentigerous cyst. Note resorption of the root of the first mandibular molar

NON INFLAMMED TYPENON INFLAMED dentigerous cyst shows a thin nonkeratinized epithelial lining.

HISTOLOGICAL FEATURES

A. NON INFLAMMED TYPE:

• Lining derived from reduced dental epithelium, consists of 2-4 cell layers of non keratinized epithelium, without rete ridges.

• Wall composed of thin fibrous connective tissue appearing immature, as it is derived from the dental papilla.

INFLAMED TYPEINFLAMED DENTIGEROUS CYST, shows a thicker epitheliallining with hyperplastic rete ridges. The fibrous cyst capsule shows a diffuse chronic inflammatory infiltrate

HISTOLOGICAL FEATURES

A. INFLAMED TYPE :

• Lining shows varying degrees of hyperplasia with rete ridges and occasionally even keratinization.

• Wall is composed of mature connective tissue which shows infiltration by chronic inflammatory cells.

• Focal areas of mucous cells can be seen in the lining. Small odontogenic epithelial islands can be seen in the wall.

DIFFERENTIAL DIAGNOSIS

Although it presents a unique feature, yet some lesions must be considered in its differential diagnosis :

1. Unicystic ameloblastoma2. Adenomatoid odontogenic tumor.

COMPLICATIONS

1. Recurrence 2. Development of

ameloblastoma.3. Development of

squamous cell carcinoma.

4. Development of mucoepidermoid carcinoma from mucus secreting cells in the lining.

ODONTOGENIC KERATOCYST / KCOT..???

• OKC’s arises from cell rests of the dental lamina. • Have a different growth mechanism and biologic behavior from

the more common dentigerous cyst and radicular cyst.• Several investigators suggest that odontogenic keratocysts be

regarded as benign cystic neoplasms rather than cysts

CLINICAL FEATURES

• AGE : In most series there has been a pronounced frequency in the second and third decades.

• GENDER : more in males than in females.• SITE : The mandible is involved far more frequently• 50% cases occur in angle region and extend to

ascending ramus and forwards to body of mandible.

siTE diSTRIbuTION

Relative distribution ofodontogenic keratocysts in the jaws.

CLINICAL FEATURES

• Pain, swelling or discharge.• Occasionally, paraesthesia of the lower lip or teeth. • Some are unaware of the lesions until they develop

pathological fractures.• In many instances, patients are remarkably free of symptoms

until the cysts have reached a large size, involving the maxillary sinus and the entire ascending ramus, including the condylar and coronoid processes.

• occurs because the OKC tends to extend in the medullary cavity and clinically observable expansion of the bone occurs late.

• GORLIN-GOLTZ syndrome, characterized by

• Multiple nevoid basal cell epitheliomas• Odontogenic Keratocyst of the jaws• Bifid ribs– sixth rib• Plantar & palmar pits• Occular hypertelorism• Frontal bossing• Ectopic calcifications

RADIOGRAPHIC FEATURES

• OKC demonstrate a well-defined radiolucent area with smooth and often corticated margins.

• Large lesions, particularly in the posterior body and ascending ramus of the mandible, may appear multilocular

• An unerupted tooth is involved in the lesion in 25% to 40% of cases; in such instances, the radiographic features suggest the diagnosis of dentigerous cyst

RADIOGRAPHIC FEATURESRadiograph of a small odontogenic keratocyst.

RADIOGRAPHIC FEATURESRadiograph of an odontogenic keratocyst with scallopedmargins.

RADIOGRAPHIC FEATURESRadiograph of a multilocular odontogenic keratocyst.

RADIOGRAPHIC FEATURES

Radiograph of an odontogenic keratocyst that has enveloped an unerupted tooth to produce a ‘dentigerous’ appearance.

HISTOLOGIC FEATURES

• The epithelial lining is composed of a uniform layer of stratified squamous epithelium,usually six to eight cells in thickness.

• The epithelium and connective tissue interface is usually flat, and rete ridge formation is inconspicuous.

• The basal cell layer has columnar / cuboidal cells with reversely polarized nuclei, imparting a “picket fence” or “tombstone” appearance.

• The luminal surface shows flattened parakeratotic epithelial cells, which exhibit a wavy or corrugated appearance.

• Small satellite cysts, cords, or islands of odontogenic epithelium may be seen within the fibrous wall .

okcEpithelial lining is 6 to 8 cells thick, with a hyperchromatic and palisaded basal cell layer. Note the corrugated parakeratotic surface.

Satellite microcysts

Satellite microcysts in the wall of an odontogenic keratocyst that appear to be arising directly from an active dental lamina.

DIFFERENTIAL DIAGNOSIS

• In case of unilocular ‘lucencies – Dentigerous cyst, Eruption cyst, COC, AOT, Unicystic ameloblastoma etc.

• In case of multilocular ‘lucencies – Conventional ameloblastoma, CEOT, Central giant cell granuloma, Aneurysmal bone cyst etc.

• COMPLICATIONS IN OKC :

1. Malignant transformation of cyst lining rare, but has been reported.

2. Recurrence – high rate of recurrence.

• REASONS FOR RECURRENCE :

1. Thin, fragile lining is very difficult to remove completely.2. New cysts develop from satellite cysts left behind.3. Some cysts may be left behind in cases of Gorlin – Gotz

syndrome.4. New cysts can also develop from basal cells of overlying oral

epithelium, especially in ramus – 3rd molar region.

ERUPTION CYST

ERUPTION CYST

• Typical c/f of an eruption cyst. Note a bluish colored, dome shaped swelling over the unerupted molar.

• The dentigerous cyst develops around the crown of an unerupted tooth lying in the bone,

• The eruption cyst occurs when a tooth is impeded in its eruption within the soft tissues overlying the bone. Eruption cysts involving the maxillary permanent

incisors.

PATHOGENESIS

The circumscribed cavity contains blood (due to surface trauma on biting with opposite tooth )

It imparts purple / deep blue color

Hence known as

• ERUPTION HEMATOMA

CLINICAL FEATURES

AGE : found in children of different ages, and occasionallyin adults if there is delayed eruption

SITE : most commonly associated with the first permanentmolars and the maxillary incisors

Radiological features

• The cyst may throw a soft-tissue shadow, but there isusually no bone involvement except that the dilated andopen crypt may be seen on the radiograph.

HISTOLOGICAL FEATURES

• Show surface oral epithelium on the superior aspect. The underlying lamina propria shows a variable inflammatory cell infiltrate.

• The deep portion of the specimen, which represents the roof of the cyst, shows a thin layer of nonkeratinizing squamous epithelium

A cystic epithelial cavity can be seen below the mucosal surface.

GINGIVAL CYST OF ADULTS

Pathogenesis

• A number of suggestions have been made about the pathogenesis of the gingival cyst in adults.

• It was originally proposed that they may arise from odontogenic epithelial cell rests; or by traumatic implantation of surface epithelium; or by cystic degeneration of deep projections of surface epithelium

Clinical features

• Signs and symptoms:• Slowly enlarging, well

circumscribed painless swelling.

• Invariably occurs on facial aspect of free / attached gingiva.

• Surface of lesion is smooth and of normal color.

• Fluctuant lesion, adjacent teeth are vital

Clinical photograph of a gingival cyst of an adult

AGE : 5th – 6th decade of life

SITE : mand. canine and Pre Molar area; attached gingiva or I/D papilla

Radiological features

Radiograph of a gingival cyst in an adult. There is a faint radiographic shadow (marked with arrows) indicative of superficial bone erosion.

Histology

• H/p features identical to Lateral periodontal cyst.

• Some cysts lined by thin, flattened stratified squamous epithelium.

• Sometimes, focal thickenings (Plaques) may be found within the lining.

The epithelial lining of a gingival cyst of the adult (G) lying contiguous to the junctional epithelium (J) of an adjacent tooth.

G

J

J

54

Low-power photomicrograph of a gingival cyst of the adult, showing a very narrow epithelial cyst lining (bottom) deep to the gingival epithelium.

Narrow epithelial lining of a gingival cyst of the adult. It resembles the reduced enamel epithelium found in dentigerouscysts.

LATERAL PERIODONTAL CYST

LATERAL PERIODONTAL CYST• Uncommon, but well recognized type of odontogenic cyst.• The designation ‘lateral periodontal cyst’ is confined to those cysts

that occur in the lateral periodontal position and in which an inflammatory etiology and a diagnosis of collateral OKC have been excluded on clinical and histological grounds.

• (Shear and Pindborg, 1975).

CLINICAL FEATURES

• Age : 20 – 60 years, peak in 6th decade.

• Sex : Male predilection.

• Site : Lateral PDL regions of mandibular premolars, followed by anterior maxilla

Signs & symptoms• Usually asymptomatic as it occurs on the lateral aspect of root of tooth.

• Occasionally pain and swelling may occur.• Associated teeth are vital, unless otherwise affected.• Cysts rarely > 1cm in size, except for BOTRYOID VARIETY which

is larger and also a multilocular lesion.

Radiological features

• Round to ovoid ‘lucency with sclerotic margins.

• Cyst can be present anywhere between cervical margin to root apex.

• Radiographically, it can be confused with collateral OKC.

Radiograph of a lateral periodontal cyst lying between the mandibular premolar teeth. The margins are well corticated, indicative of slow enlargement.

Radiological features

Lateral periodontal cyst. Radiolucent lesionbetween the roots of a vital mandibular canine and first premolar.

Lateral periodontal cyst. A larger lesion causingroot divergence.

HISTOLOGICAL FEATURES

Lateral periodontal cyst which in part has a thin, nonkeratinised stratified squamous epithelial lining resembling reduced enamel epithelium. Two epithelial plaques are seen. The one on the right is convoluted

HISTOLOGICAL FEATURES

• The lateral periodontal cysts were lined by a thin, non-keratinising layer of squamous or cuboidal epithelium usually ranging from 1 to 5 cell layers wide, which resembled the reduced enamel epithelium

• The epithelial cells were sometimes separated by intercellular fluid. Their nuclei were small and pyknotic.

• An interesting feature seen in many of the lateral periodontal cysts was the presence of what appear to be localised plaques or thickenings of the epithelial lining

• Small epithelial nests may be seen in connective tissue wall, which may show signs of mild inflammation.

Diagram illustrating the possible mode of formation of epithelial plaques by localised proliferation of cells. (a) Cyst lined by thin epithelium resembling reduced enamel epithelium. (b) Early epithelial thickening by basal cell proliferation. (c) Basal cells continue to proliferate. Superficial cells swell by accumulation of intracellular fluid. (d) and (e) Basal proliferation ceases or slows down. Superficial cells are waterlogged and swollen. Plaque protrudes into cyst cavity and cyst wall where it can undermine and raise adjacent cyst lining. (f) Epithelial plaque can form convolutions. Protrusions into cyst wall as in (c–f) may be ‘pinched off’ and develop into daughter cysts, leading to the formation of the botryoid variety of lateral periodontal cyst.

64

CALCIFYING ODONTOGENIC CYST

• Also called as Odontogenic ghost cell cyst or Gorlin cyst.• In the latest WHO publication on odontogenic tumours

(Prætorius and Ledesma-Montes, 2005) it was classified as a benign odontogenic tumour and was renamed calcifying cystic odontogenic tumour (CCOT).

Clinical FeAtures

• Age : Wide range, peak in 2nd decade.

• Sex : Equal.

• Site : Anterior segment of both jaws

Classification and Pathogenesis

• COC is a unicystic process and develops from the reduced dental epithelium or remnants of dental lamina.

• The cyst lining has the potential to induce formation of dentinoid or even odontoma in adjacent CT wall.

Signs & symptoms

• Swelling is the commonest complaint, seldom associated with pain.

• Intraosseous lesions can cause hard bony expansion and resulting facial asymmetry.

• Displacement of teeth can also occur.

RADIOLOGICAL FEATURES• Intraosseous lesions produce

well defined ‘lucency which is usually unilocular.

• Irregular calcified masses of varying sizes may be seen within the lucency.

• Displacement of root/roots with or without root resorption and expansion of cortical plates also seen

Radiograph of a calcifying odontogenic cyst of the maxilla. There is a well-demarcated margin and calcifications suggestive of tooth material.

RADIOLOGICAL FEATURES

Radiograph of a calcifying odontogenic cyst with well-demarcated margins extending from the right to the left premolar regions of the mandible. Numerous calcifications are present, some suggestive of small denticles.

Histological features

• Lining is usually thin about 6 – 8 cell thick, may be thickened in other areas.

• Lining shows characteristic odontogenic features with reversely polarized basal cell layer.

• TYPICALLY – GHOST CELLS may be seen in thicker areas of lining.

• Ghost cells are enlarged, ballooned, ovoid, eosinophilic cells with well defined cell boundaries.

• Some times many cells may fuse.• They represent abnormal keratinization and frequently calcify.• Tubular dentinoid and even complex odontome may be found

in connective tissue wall close to epithelial lining.

Histological featuresHistological features of a calcifying odontogenic cyst with clusters of fusiform ghost cells and focal calcifications, lying in a stratified squamous epithelium.

Histological features

In this calcifying odontogenic cyst, there are sheets of ghost cells and a focal area in which there has been induction of a strip of dysplastic dentine (dentinoid).

DIFFERENTIAL DIAGNOSIS

• Based on radiographic appearance, following lesions must be included in the provisional diagnosis –• Ameloblastoma• CEOT• AOT• Ameloblastic fibro odontoma

75

Nasopalatine duct Cyst / Incisive canal cyst

Nasopalatine Duct (Incisive Canal) Cyst

• Also classified as “FISSURAL CYSTS”.

• Believed to be derived from epithelial remnants included during closure of embryonic facial processes.

• Controversy – actual “closure” of embryonic processes does not occur. Grooves between processes is smoothed by proliferation of underlying mesenchyme.

• Usually occurs within the nasopalatine canal or in soft tissue of palate at the opening of canal.

CLINICAL FEATURES

• Age : 4th, 5th & 6th decades.

• Sex : More in females

• Frequency: Commonest non odontogenic developmental cyst

PATHOGENESIS• In lower animals, the NP duct concerned with olfactory sensation – in humans only vestigial remnants persist in incisive canal in form of epithelial islands, ducts, cords etc.

• These nests can show central degenration to form cysts. Etiology for cyst transformation is yet unclear.

• Some believe, it may arise spontaneously like an OKC.

Signs & symptoms

• Commonest symptom is swelling, usually in anterior region of mid palate.

• Swelling can also occur in midline on labial aspect of alveolar ridge.

• If pressure on NP nerves – pain

• Exclude possibility of periapical cyst by testing vitality of incisors.

Nasopalatine Duct (Incisive Canal) Cyst

Small nasopalatine cyst presenting as a soft ovoidswelling in the midline of the maxilla, posterior to the central incisor teeth.

Large nasopalatine duct cyst extending laterally andposteriorly to involve much of the hard palate.

RADIOLOGICAL FEATURES

• Seen as lucency usually in incisive canal – DIFFICULT TO DISTINGUISH FROM A NATURALLY LARGE INCISIVE CANAL.

• Lucency with AP dimension upto 10 mm considered as enlarged incisive canal, but if lucency < 14 mm, then NP duct cyst.

• The lucency appears well defined with sclerotic borders, in midline of palate between roots of incisors.

RADIOLOGICAL FEATURES

Radiograph of a nasopalatine duct cyst showing a pear-shaped radiolucency in the anterior maxilla. The lamina dura on the left is intact although the apex appears to be in the cyst.

Histological features

• Lining epithelium extremely variable, consisting of stratified squamous, pseudo stratified columnar, simple columnar or cuboidal epithelium.

• Most commonly lining is stratified squamous followed by pseudo stratified columnar.

• A useful diagnostic aid – presence of large nerve and vascular bundles in connective tissue wall.

Histological features

Neurovascular bundle in the wall of a nasopalatine duct cyst.

DIFFERENTIAL DIAGNOSIS

• Radicular cyst, if it is associated with a pulpally involved tooth.

• Large incisive canal.

NASOLABIAL CYST

NASOLABIAL CYST

• The nasolabial cyst occurs outside the bone in the nasolabial folds below the alae nasi.

• It is traditionally regarded as a jaw cyst although strictly speaking it should be classified as a soft tissue cyst.

Clinical features

• Age : Peak incidence in 4th & 5th decades.

• Sex : More in females.

• Frequency: Rare in occurrence.

Signs & symptoms

• Commonest complaint – slowly growing swelling and occasionally, pain and difficulty in nasal breathing.

• Extra orally – filling out of nasolabial fold and may lift ala nasi.

• Intra orally – bulge in labial sulcus.

• Fluctuant lesion.Nasolabial cyst producing a swelling of the right upper lip, forming a bulge in the labial sulcus.

PATHOGENESIS

• Believed to develop from lower anterior portion of nasolacrimal duct.

• When margins of lateral and maxillary processes fuse, ectoderm along boundary between them gives rise to solid cellular rod which first develops as a linear surface elevation (Nasolacrimal ridge) and then sinks into underlying mesenchyme.

• This solid rod canalizes to form NL duct.• The NL cysts are located such that it is possible that they develop

from embryonic remnants of NL duct.• Importantly, a mature NL duct is lined by pseudo stratified

columnar epithelium, which is also the lining of NL cyst.

RADIOLOGICAL FEATURES

• Difficult to interpret on radiograph.

• May be seen as localized increased lucency of alveolar process above apices of incisors.

• Lucency results from pressure resorption on labial surface of maxilla.

Standard occlusal radiograph of a patient with a nasolabial cyst. There is a posterior convexity of the left half of the radiopaque line that forms the bony border of the nasal aperture.

HISTOLOGICAL FEATURES

• Cyst lined by non ciliated pseudo stratified columnar epithelium.

• Goblet cells also seen in some cases.

• Occasionally, part of lining may be cuboidal / flat squamous.

• Conncetive tissue wall is fibrous, relatively acellular with fibers arranged loosely or compactly.

Nasolabial cyst lined by a pseudostratified columnar epithelium containing many goblet cells. In the example illustrated here, mucous glands are present in the wall.

RADICULAR CYST

RADICULAR CYST

• Also called APICAL PERIODONTAL CYST• Radicular cysts are the most common inflammatory cysts and

arise from the epithelial residues in the periodontal ligament as a result of periapical periodontitis following death and necrosis of the pulp.

• Quite often a radicular cyst remains behind in the jaws after removal of the offending tooth and this is referred to as a residual cyst.

CLINICAL FEATURES

• Age : peak in 3rd, 4th and 5th decades.

• Sex : Slightly more in males.

• Site : Maxillary anterior region.

• Frequency: Commonest cystic lesion of jaws.

Signs & symptoms

• Primarily symptom less.• Discovered accidentally during routine dental X ray exam.• Slowly enlarging hard bony swelling initially. Later, if cysts

breaks through cortical plates, lesion becomes fluctuant.• Diagnostic criteria – associated teeth are non vital• Rare in deciduous teeth.

RADIOLOGICAL FEATURES

• Classically presents as round / ovoid lucency with sclerotic borders and associated with pulpally affected tooth / teeth.

• If infection supervenes, the margins become indistinct, making it impossible to distinguish it from a peripaical granuloma.

Radiograph of a radicular cyst. The lesion is a well defined radiolucency associated with the apex of a non-vital root filled tooth.

98

HISTOLOGICAL FEATURES

• Lined partly / completely by non keratinized epithelium of varying thickness.

• Epithelium usually shows arcading around the connective tissue.

• The connective tissue wall shows inflammatory infiltrate

mainly in the form of lymphocytes and plasma cells.• Hyaline / Rushton bodies are found in epithelium and rarely in

connective tissue wall.• These are curved or linear structure with eosinophilic staining

properties

HISTOLOGICAL FEATURES

• Cholesterol crystals in from of clefts are often seen in the connective tissue wall, inciting a foreign body giant cell reaction.

• Originate from disintegrating RBC’s in presence of inflammation.

• Different types of dystrophic calcification are also seen in connective tissue wall.

• Mucus cell metaplasia as well as respiratory cells may be seen in the epithelial lining.

• Keratinization if found is due to metaplasia and must not be confused with an OKC.

HISTOLOGICAL FEATURES

Quiescent epithelium lining a mature, long-standing radicular cyst (H & E).

Mucous cells in the surface layer of the stratified squamous epithelial lining of a radicular cyst (H & E).

HISTOLOGICAL FEATURES

Hyaline bodies in the epithelial lining of a radicularcyst (H & E).

Mural nodule of cholesterol-containing granulationtissue fungating into the cavity of a radicular cyst (H & E).

103

Residual Cysts

Residual cysts

• Radiographic appearance of a large residual cyst left behind after extraction of 1st mandibular molar.

• The histopathological features of the residual cyst are similar to those described above for conventional radicular cysts. However, because the cause of the cyst has been removed, residual cysts may progressively become less inflamed so that eventually the cyst wall is composed of uninflamed

• The epithelial lining may be thin and regular and indistinguishable from a developmental cyst such as a dentigerous cyst or lateral periodontal cyst.

DIFFERENTIAL DIAGNOSIS:

• Following lesions must be distinguished from other periapical radiolucencies–

•1. Periapical granuloma2. Peripaical cemento – osseous dysplasia (early lesions)

Paradental Cysts

Paradental Cysts

• A cyst of inflammatory origin- occurring on lateral aspect of root of partially erupted mandibular 3rd molar with an associated history of pericoronitis

• Age : 20-40 years

• Tooth is vital

• Facial swelling

• Facial sinus in some cases

Radiographic features

• Affected tooth is tilted • Well demarcated

RadioLucency distal to partially erupted tooth

• Lamina Dura is intact• New bone may be laid

down

a

b

(a,b) Two cases of bilateral paradental cysts associated with erupting mandibular third molar teeth. The cysts are distal and buccal to the involved teeth. Note that the periodontal ligament space is not widened and that the distal part of the cyst is separate from the distinct distal follicular space.

Histological features

• The cysts are lined by a hyperplastic, non-keratinised, stratified squamous epithelium which may be spongiotic and of varying thickness.

• An intense inflammatory cell infiltrate was present associated with the hyperplastic epithelium and in the adjacent fibrous capsule is the seat of an intense chronic or mixed inflammatory cell infiltrate. fibrous capsule

Paradental cyst adjacent to the root of an impacted mandibular third molar. The cyst is lined by non-keratinised stratified squamous epithelium of variable thickness and showing areas of proliferation (H & E).

Aneurysmal Bone Cyst

Aneurysmal Bone Cyst

• Uncommon cyst, found mostly in long bones and spine.

• CLINICAL FEATURES: -1. Age : First 3 decades.2. Sex : Mainly females.3. Site : molar regions of mandible & maxilla.

• Signs & symptoms: • Hard, rapidly growing swelling which can cause malocclusion. • If lesion perforates cortical plates, can cause “egg shell

crackling”.

PATHOGENESIS

• Controversy whether lesion arises de novo or from a vascular disturbance in the form of sudden venous occlusion or development of an AV shunt occurring secondarily in a pre existing lesion like central giant cell granuloma, Osteosarcoma etc.

• Due to the malformation, change in hemodynamic forces occurs which can lead to ABC.

RADIOLOGICAL FEATURES

• Classically seen as a unilocular, ovoid / fusiform lucency which balloons the cortical plates.

• Teeth displacement and root resorption also observed.

• Lesions are usually unilocular but longer-standing lesions may show a ‘soap-bubble’ appearance and may become progressively calcified

Radiograph of an aneurysmal bone cyst involving the angle and ascending ramus of the mandible. There is a ballooning expansion of the cortex.

Histological features

• It consist of many capillaries and blood-filled spaces of varying size lined by flat spindle cells and separated by delicate loose-textured fibrous tissue

• Most lesions contain small multinucleate cells and scattered trabeculae of osteoid and woven bone.

• In some of the solid areas, sheets of vascular tissue, containing large numbers of multinucleate giant cells, fibroblasts, haemorrhage and haemosiderin, look very much like giant cell granuloma of the jaws

• The diagnosis is made primarily on the basis of the clinical and radiological features because histologically such solid lesions may be indistinguishable from giant cell granuloma.

Histological features

Aneurysmal bone cyst in which the solid areas have histological features identical to those of the central giant cell granuloma of the jaws (H & E).

Aneurysmal bone cyst of the mandible. The solid areas show the features of cemento-ossifying fibroma and a portion of one of the many cystic spaces is present at the top of the photomicrograph(H & E).

DIFFERENTIAL DIAGNOSIS

• Conventional ameloblastoma• CEOT• Central giant cell granuloma

Solitary Bone Cyst

Solitary Bone Cyst

• Also called as Hemorrhagic bone cyst, or Traumatic bone cyst.

• Commonly seen in mandible, rare in maxilla.

• Identical to solitary bone cyst of humerus in children and adolescents.

CLINICAL FEATURES

• Age : Young individuals

• Sex : Equal

• Site : Body and symphysis menti of mandible.

PATHOGENESIS

• Numerous theories have been proposed.

• First theory – cyst may follow trauma to bone which causes intra medullary hemorrhage which fails to organize. This clot subsequently liquefies - CYST.

• Recent theory osteogenic cells fail to differentiate locally and thus instead of bone, the undifferentiated cells form synovial tissue.

Signs & symptoms

• Asymptomatic.

• Rarely, swelling and pain may be seen.

• Half of all patients give a history of trauma to the area.

RADIOLOGICAL FEATURES

• Appears as a lucency with irregular but well defined edges and slight cortication.

• On occlusal view the ‘lucency is seen to extend along cancellous bone.

Radiograph of a solitary bone cyst involving anextensive area in the right body of the mandible. Thisexample has a well-defined margin with cortication.Interradicular scalloping is a prominent feature.

HISTOLOGICAL FEATURES

• Lumen not lined by any epithelium (Pseudo cyst).

• Wall shows loose fibro vascular connective tissue.

• Hemorrhage and hemosiderin pigment usually present.

• Multinucleated giant cells scattered within the connective tissue.

• Adjacent bone shows osteoclastic resorption on inner surface.

A solitary bone cyst of the jaw. The lining is composed of loose vascular fibrous tissue with osteoclastic activity on the surface of the adjacent bone (H & E).

DIAGNOSIS

• RADIOLOGY

a. Periapical x-raysb. Occlusal view x-raysc. Lateral oblique view x-raysd. Panoramic x-rayse. P.A view x-raysf. Sinus view x-rays• C.T.SCAN• RADIOPAQUE DYES• ASPIRATION• BIOPSY

Various Aspirates PATHOLOGY ASPIRATE Other Findings of Aspirates

Dentigerous Cyst Clear, pale straw colour fluid

Cholesterol crystals. Total protein in excess 4 g / 100ml. Resembles serum

Odontogenic Keratocyst Dirty, creamy white viscoid suspension

Para keratinized squames. Total protein less than 4 g /100ml. Mostly albumin

Periodontal Cyst Clear, pale yellow straw colour fluid

Cholesterol crystals. Total protein 5 — 11g / 100ml

Infected Cyst Pus, brownish fluid Polymorphonuclear leukocytes, ,Cholesterol clefts

Mucocele, Ranula Mucus -----

Gingival Cysts Clear fluid -----

Various Aspirates

PATHOLOGY ASPIRATE Other Findings of Aspirates

Solitary Bone Cyst Serous fluid, blood or empty cavity

Necrotic blood clot

Stafne’s Bone Cyst Empty cavity – yield air ---

Dermoid Cyst Thick sebaceous material ---

Fissural Cyst Mucoid fluid ----

Treatment• Cysts of the jaws are treated in one of the following four basic

methods:

(1) Enucleation, (2) Marsupialization, (3) A staged combination of the two procedures, and (4) Enucleation with curettage.

129

Pictorial Conclusion...

130

Pictorial Review...

131

The biopsy report is as good as the tissue

specimen….

• References :

1. Cysts of Oral and maxillofacial region, Shear.2. Contemporary Oral and Maxillofacial Pathology, Sapp,

Eversole, Wysoki.3. Shafer’s Textbook of Oral Pathology.