Calcifying odontogenic cyst(Gorlin cyst).

8)Calcifying odontogenic cyst(Gorlin cyst).

Calcifying odontogenic cyst is as un common lesion which is widely considered to represent a cyst. Some invetigators classify it as a neoplasm (the solid variant) {Dentinogenic ghost cell tumor} .WHO groups calcifying odontogenic cyst with all its variants (ghost cell tumor, malignant ghost cell carcinoma with cytologic atypia & calcifying odontogenic cyst ) as a neoplasm rather than cyst.

Origin,

Epithelial rests of serres (rests of dental lamina) either in soft tissue or bone.

Clinical features,

-Site of this cyst is predominanrly intraosseous,but 25% occurs occasionally in soft tissue of the gingiva (extra-osseous) or (peripheral).Mostly occurs anterior to first molar in incisors and canine region,it affects mandible and maxilla.

-Below 40 years old.

-Symptomless.

-Extraosseous or peripheral lesions appear as localized gingival mass resemble fibromas, gingival cysts and peripheral giant cell granulomas.

Radiographic picture,

Well-defined unilocular radiolucent area or multilocular containing varying amounts of radiopaque calcified materials.

N.B: Some authors say that 30% of gorlin cysts are associated with crown of uneupted teeth, some exhibit that gorlin cyst is of priomordial origin and develops from rests of serres and so it is not associated with crown of impacted tooth and that all gorlin cysts occurs between 2 teeth.

Histopathological features,
-Basal cell layer lining is of cuboidal or columnar cells resembles ameloblasts (ameloblasts-like), the overlyning layer of loosly arranged stellate reticulum -like cells.

-The most characteristic hidtopathological feature of calcifing odontogenic cyst is the presence of Ghost cells, which are eosinophilic altered epithelial cells characterize by loss of nuclei with preservation of cell outline.

-These ghost cells undergo keratinization and calcification, they appear first as basophilic granules (keratinized ghost cells) then it may increase in size to form calcified materials (calcified ghost cells), these calcified ghost cells is the feature which is responsible for radiopacities in the radiographic picture.

-In some cases epithelial lining ,ghost cells, proliferate into lumen so that the lumen is largely filled with masses of calcified ghost cells and the lesion becomes solid (solid ghost cell tumor variant), and as a result of contact between ghost cells and connective tissue ,a foregin body reaction may be elicited due to their exudation of keratin so multinucleated giant cells may be seen.

multi nucleated giant cells

-Areas of aneosinophilic materials may be present that is considered by some authors to represent dysplastic dentin [dentinoid] as a result of inductive effect by odontogenic epithelium into mesenchymal tissues.

-About 20% of these cysts seen with the conjucation of odontomas.

-Some ameloblastomas have ghost cell differentiations giving rise to the concept that calcifying odontogenic cyst may be associated with ameloblastoma ,still Query?

The solid variant

The cystic variant

Treatment,
Enucleation.

Sum up:

Calcifying odontogenic cyst or Gorlin cyst is a developmental cyst develops in bone between 2 teeth or may in soft tissue and has 2 solid variants: odontogenic ghost cell tumor and odontogenic ghost cell carcinoma .

N.B: Calcifying epithelioma of malherbe is a cutaneous counterpart of calcifying odontogenic cyst.

Glandular odontogenic cyst

7)Glandular odontogenic cyst{Sialo-odontogenic cyst}

It's a rare developmental cyst and represents one of 3 possibilities:

1] may be a true cyst of glandular origin from either entrapped salivary gland tissues or epithelial rests that differentiate into glandular epithelium.

2]or may be odontogenic in origin cyst in which epithelial lining undergoes metaplasia into glandular epithelium.

3] A low grade mucoepidermoid carcinoma that forms a single cystic space instead of the usual multicystic spaces.

Clinically,

occurs mainly in middle-aged adults,common in mandibular anterior region of the jaw,painless.

Radiographically,

Unilocular or more common multilocular radiolucent area.

Histopathological features,

-Lining is stratified squamous epitheluim ,superficial layer tends to be columnar or cuboidal epithelial cells.

-Interface between epithelium and fibrous tissue is flat ,fibrous capsule is devoid from inflammatory cells.

-Cilia covering luminal surface may be noted.

-amucous cells may be found within lining with pools of mucin.

-Crypts(cyst-like spaces) may be found within lining.

-Focal thickness may be sen as in lateral periodontal cyst.

Treatment,

Enucleation, this cyst shows a tendency for recurrence.

Gingival cyst of the adult

B] Gingival cyst of the adult.

-It's uncommon cyst and considers to be the soft tissue counter part of the lateral periodontal cyst.

Origin,

Dental lamina rests.

Clininal & radiographic picture,

-As lateral periodontal cyst , it develops mainly in mandibular bucccal gingiva of alveolar mucosa in canine & premolar areas.

-Painlaess dome-like swelling less than 1 Cm in diameter or more, bluish or bluish grey in color due to thinning of alveolar mucosa.

-occrs mainly over age of 40 years.

-If long standing: may cause a superficial "cupping out " of the alveolar mucsa which is usually not detected in radiographic x-ray but apparent when the cyst is excised and if more bone is missing, it may be in this case a lateral periodontal cyst which erodes bone to gingival soft tissue rather than gingival cyst which originated in the mucosa.

Histologically,
Lining of thin flat stratified squamous epithelium with focal plaques & clear cells very similar to lateral periodontal cyst.

Treatment,

Excision.

Gingival cyst of the newborn

6) Gingival cyst.

A] Gingival cyst of the newborn.

B] Gingiva cyst of dult.

A] Gingival cyst of the newborn.

-Also known as (Alveolar cyst), (Dental lamina cysts) .

-They are small supeficial multiple whitish keratin -filled papules present on maxillary alveolus (edentulous ridge of infants).

-These cysts arise from rests of dental lamina , they are common lesions appear in 50% to 80% of neonates.

Histopathology,

The lining is thin flattened epithelium of parakeratotic surface , the lumen contains keratin.

Treatment,

No treatment is required, most lesions involute or resolve spontaneously by 3 months of age as aresult of rupture of these cysts.

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Similar scenario may occur in the midline of palate where similar inclusion cysts ( Epstein's pearls ) or ( Bohn's nodules) also found in the midline of soft or hard palate.

-Origin of the two cyst has been theorized that may arise in one of the two ways :

1} May from Epithelial cell entrapment during fusion of palatal shelves.
2} Or may from epithelial remnants derived from development of minor salivary glands of palate.

-These cysts are similar to gingival cysts of neonates clinically, histopathologically and in treatment and the only difference that they develop in the palate not alveolar ridge.

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Botryoid odontogenic cyst

5) Botryoid odontogenic cyst

-It's avariant of and even rarer than lateral periodontal cyst.

-Like lateral periodontal cyst ,it affects mandibular canine and premolar region more.

-This lesion may be polycystic and subsequently ,it appears multilocular radiographically but may appears uniloclar radiolucent area.

-Grossly, it resembles a bunch of grapes ( grape-like clusters) and so the name botryoid.

-Has apotential for recurrence.

Lateral periodontal cyst

5)Lateral periodontal cyst.

-Lateral periodontal cyst is adevelopmental cyst occurs at lateral root surface of avital tooth, it represents the intrabony counterpart of the gingival cyst of the adult.

-Lateral periodontal cyst has adistinctive clinical and microscopic features that distinguish it from lateral radicular cyst and odontogenic keratocyst that occurs or may occur in the same region.

Origin,

-It arises from rests of dental lamina (epithelial rests of serres).

Clinical features,

-It's an asymptomatic cyst.

-Occurs in middle age.
- Most common in canine and premolar region & incisors.

-Affects mandible mainly and also in maxilla.

-Associated with vital tooth.

Radiographic picture,

-Well-circumscribed unilocular radiolucent area lateral to root surface of a vital tooth.

-Mainly tear -drop shaped radiographic picture and may be rounded.

Histological picture,

-Epithelial lining is non-keratinized stratified squamous epithelium and may be cuboidal with no inflammation.

-Focal nodular thickenings of epithelial lining may occur i.e thickenings or plaques may be seen within lining.

-Clear cells rich in glycogen may be found within plaques or elsewhere in the lining.

See focal plaque epithelial thickness

Clear cells contain
glycogen

Treatment,

Enucleation with no recurrence.

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Orthokeratininzed odontogenic cyst

4) Orthokeratininzed odontogenic cyst

Orthokeratinized odontogenic cysts were called the orthokeratinized variants of odontogenic keratocyst but , it's now accepted that these lesions are different totally from parakeratinized odontogenic keratocysts. so it is disscused in aseparate category.

Clinical features,

- this lesion occurs predominantly in young adults.

-male to female ratio is 2:1.

- more in mandible than maxilla.

-this lesion has no clinical features that differentiate it from other inflammatory and deveopmental cysts.

Radiographic picture,
Also this lesion has no radiographic features that differentiate it from other odontogenic cysts, it appears unilocular or multilocular radiolucent area, may be associated with unerupted tooth ,may be small or large radiolucency.

Histological features,

Lining is composed of stratified squamous epithelium shows orthokeratinized surface with prominent granular cell layer below it, no basal cell palisading and lining is usually flat and no corrugation.

Treatment,

-Enucleation with curretage.

-Rarely recur.

-Not associate with nevvoid basal cell carcinoma syndrome as kertocyst.

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Odontogenic keratocyst

3) Odontogenic keratocyst.

-Odontogenic cyst , or as some authers call primordial cyst, is adevelopmental cyst characterized by unusual growth pattern and high tendency to recur.

-It represents 10 % of all odontogenic cyst.

-Several investigators suggest that odontogenic keratocyst be regarded as benign cystic neoplasm (Keratinizing cystic odontogenic tumor) rather than cyst.

Origin,

Mostly arises from epitelial rests of serres ( rests of dental primordium "dental lamina") Or arises from extension of the basal cell layer of oral epithelium.

Cinical features,

-Keratocyst occurs at any age and have apeak incidence within second and third decades.
-There is male predilection.

-It may occur at any region of the jaw ,but 70% to 80% of cases occur in mandibule especially posterior mandible and ascending ramus.

-Keratocysts are usually asymptomatic ,but some large keratocysts may be associated with pain and swelling as large cysts may rupture and leak keratin into the surrounding tissues provoking inflammatory response that causes pain and swelling.

-This cyst grows in an anterior posterior direction and can reach large size without causing facial asymmetry or bone expansion,this feature may be useful in clinical differential diagnosis as dentigerous and radicular cyst usually associated with bone expansion.

-Multiple odontogenic keratocyst may present and such patient should be evaluated for other manifestations of the nevoid basal cell carcinoma (Gorlin-goltz syndrome ).

Radiographic picture,

-Well defined unilocular or multilocular radiolucent area appears surrounded by radiopaque margin, it may resemble dentigerous cyst associated with unerupted 3rd molar but crown of the tooth is usually separated from cystic cavity.

-Keratocyst may present in jaws of edentulous patients and in this case it cannot be diferentiated radiographically from residual radicular cyst.

-Keratocyst may develop between two teeth an in this case it gives the radiologic picture of lateral periodontal cyst.

-Keratocyst may develop in the midline of maxilla and in this case it mimics ( mimicking ) naso palatine duct cyst.

Odontogenic keratocyst between two teeth resemble lateral periodontal cyst

Histopathological features,

-The epithelial lining shows regular continous layer of parakeratinized stratified squamous epithelium, 6 to 8 layers in thickness.

-Basal cell layer consists of palisaded columar or cuboidal cells with hyperchromatic nuclei that make mitosis for expansion and growth.

-The luminal surface ,which shows parakeratotic surface, exhibits wavy or corrugated appearance.

-the fibrous wall is thin and free from inflammatory cells,epithelial lining is weakely attached to the fibrous wall i.e there is separation of lining from C.T wall.

-The interface between lining and C.T is flat with no epithelial rete ridges.

-Additional histologic feature that may occasionally be encountered is the presence of satellite cyst or daghter cyst in C.T as aresult of budding of basal cell layer into connective tissue.

Palisaded basal cell layer

See separation of lining from C.T capsule

-If the cyst is secondarily inflammed , the typical features of odontogenic keratocyst may be altered , the parakeratininzed luminal surface will disappear, rete ridges may be formed with the loss of characteristic palisaded basal cell layer and then resembles inflammatory radicular cysts, and becomes indistinguishable.

Inflammed keratocyst with loss of characteristic features

N.B1: the term odontogenic keratocyst must not be used to describe any odontogenic cyst producing keratin as there are other odontogenic cysts as radicular and dentigerous cysts may rarely produce keratin by squamous metaplasia.

N.B2: some investigators recognize orthokeratinized variant of keratocyst but it loses most typical characteristic features of keratocyst as palisading and it is more logical to discuss orthokeratininzing cysts separately.

Growth & expansion,

Keratocyst tends to expand in an anteroposterior direction, growth of this cyst occurs mainly by mitosis which characterize keratocyst than other odontogenic cysts,this mitotic activity that responsible for corrugation or folding in the cyst lining and projections of the cyst into cancellous spaces resulting in multicentric pattern of growth.Keratocyst also can grow by osmosis & bone resorping factors.

Treatment & prognosis,

-The treatment of keratocyst is variable , most keratocysts are removed by enucleation and curretage, many surgeons recommend ostectomy of the bony cavity to reduce recurrence, others advocate chemical cauterization of the bony cavity by carnoy's solution to free the cyst from bony cavity, some introduce another method by insertion of apolyethylene drainage tube to allow decompression and reduction of size of cystic cavity.

-Keratocyst has ahigh tendency for recurrence and this may be due to thin fragile lining which is difficult to enucleate, or from finger like extension into cancellous spaces ,may due to satellite (daughter ) cyst left after treatment inside the bone, or may due to remnants of dental lamina producing another new cyst ( pseudorecurrence).

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