Chapter 30. Odontogenic Cysts and Tumors

Chapter 30.Odontogenic Cysts and Tumors1. Odontogenic cysts and tumors - uncommon lesions in oral and maxillofacial region - odontogenic : derivation from tooth-related apparatus

2. Three major tissue in odontogenesis 1) enamel organ : oral ectoderm origin 2) dental follicle : ectomesenchymal origin 3) dental papilla : ectomesenchymal origin

1. - - : -

2. 1) : 2) : 3) :

23. Odontogenesis 1) dental lamina : apical proliferation from oral mucosa of epithelium 2) bud stage 3) cap stage : enamel organ formation 4) bell stage - degeneration of dental lamina - remained dental lamina : development of several odontogenic cysts and tumors

3. 1) : 2) 3) : 4) - - :

34. Four epithelium of the enamel organ 1) inner enamel epithelium : ameloblastic layer tooth enamel 2) stratum intermedium 3) stellate reticulum 4) outer enamel epithelium4. 1) : 2) 3) 4)

45. Reduced enamel epi. - enamel organ epi. atrophies - accumulation of fluid between reduced enamel epi. and enamel dentigerous or follicular cyst

6. Cell cycle - G1(gap 1) S(DNA synthesis) G2(gap 2) M(mitosis) - G1 S : key step of progression of cyst or tumor

5. - -

6. - G1(1 ) S(DNA ) G2(2 ) M() - G1 S :

57. Odontogenic cysts - epi.-lined cyst in bone : only in the jaws - from odontogenic epi. - two types (Table 30-1) i) developmental : origin unknown ii) inflammatory : result of inflammation

7. - : - - ( 30-1) i) : ii) : 61) Dentigerous Cyst (1) General Features - prevalence in unerupted Mn. 3rd molars - other : Mx. 3rd molars, canines, Mn. 2nd premolars - rare in primary teeth - common in 10~30 years old, male > female, Whites > Blacks - well-defined unilocular radiolucency - epi. lining surrounding crown and root - unilocular processes - central, lateral, circumferential variety - D/D : enlarged dental follicle - noninflamed dentigerous cyst : thin epi. lining - inflamed dentigerous cyst : hyperplastic rete ridges

1) (1) - 3 - : 3, , 2 - - 10~30 , > , > - - - - , , - : - : - :

71) Dentigerous Cyst (1) General Features (2) Treatment and Prognosis - treatment : enucleation, marsupialization(large cyst), removal of tooth, curettage - need for histopathologic examination - prognosis : excellent, rare recurrence

1) (1) (2) - : , ( ), , - - : ,

82) Odontogenic Keratocyst (1) General Features - distinctive form of developmental odontogenic cyst - derived from remnants of dental lamina - sporadic cyst, nevoid basal cell carcinoma associated cyst - need for adequate diagnosis and treatment i) aggressive ii) high recurrence rate iii) association with nevoid basal cell carcinoma - prevalence in 10~40 years old, male > female, posterior mandible and ascending ramus

2) (1) - - - , - i) ii) iii) - 10~40, > ,

92) Odontogenic Keratocyst (1) General features (continued) - multilocular or unilocular - D/D : dentigerous cyst (unilocular radiolucency) - histologic findings i) stratified squamous epi. layer (6~8 cells) ii) thin and orthokeratinized epi. iii) no prominent palisaded basal layer iv) corrugation v) daughter cysts2) (1) () - - : ( ) - i) (6~8 ) ii) iii) iv) v)

102) Odontogenic Keratocyst (1) General Features (2) Treatment and Prognosis - treatment : enucleation(in one piece) and curettage - prognosis : high recurrence rate (2.5~62,5%) - suggested mechanism for recurrence i) remnants of dental lamina within the jaws ii) incomplete removal of cyst iii) remaining rests of dental lamina and satellite cysts - histopathological findings : increased expression of IL-1a, IL-6, PCNA and Ki-67

2) (1) (2) - : ( ) - : (2.5~62.5%) - i) ii) iii) - : IL-1a, IL-6, PCNA Ki-67

113) Nevoid Basal Cell Carcinoma Syndrome (1) General Features - Autosomal dominant inherited condition - Cause: mutation in the PTCH tumor suppressor gene on chromosome 9q22.3-q031 - Frontal & temporoparietal bossing - Hypertelorism - Mandibular prognathism - Bifid ribs & lamellar calcification of the falx cerebri - Tendency to develop multiple basal cell carcinoma - Pitting defects on the palms and soles - 1st manifestation for diagnosis: discovery of multiple odeontogenic keratocysts

3) (1) - - : q22.3-q31 PTCH - - - - - - - - =

123) Nevoid Basal Cell Carcinoma Syndrome(continued) (2) Treatment and Prognosis - Treatment: Marsupialization (desirable) Resection(not recommended) - Prognosis: recurrence is common, due to the retained rests of the dental lamina.

3) () (2) - : () ( ) - :

134) Glandular Odontogenic Cyst (1) General Features - aggressive, recurrent - pluripotentiality in spite of odontogenic origin - most common in middleaged adultsmost common in the anterior Mn region, frequently crossing the midlineeither unilocular or multilocular radiographicallyD/D: mucoepidermoid carcinomaglandular odontogenic cyst : typically thinner epithelial lining mucoepidermoid carcinoma : more solid and microcystic epithelial proliferations

4) (1) - - - : : :

144) Glandular Odontogenic Cyst (continued) (2) Treatment and Progonosis - treatmentenucleation and curettageresection, when considering the recurrence rate of this disease

4) () (2) - ( 155) Calcifying Odontogenic Cyst (1) General features histopathologically diverse and clinically variableclassified as a neoplasm by some authorsoften associated with the odontomaghost cell keratinization & characteristic microscopic featurespredominantly an intraosseous lesionage range : from infant to elderlyCOCs associated with odontomas tend to occur in younger patientsneoplastic variant of the COC tend to occur in elderly patients.radiophically unilocular and well-definedradiopaque structures within the lesion: irregular or toothlike5) (1) :

165) Calcifying Odontogenic Cyst (Continued) (2) Treatment and Prognosis - enucleation and curettage- association with another odontogenic tumor the prognosis tends to be the same as for the associated tumor5) () (2) - -

172. Odontogenic Tumors- inductive interactions between odontogenic epithelium and odontogenic ectomesenchymesubclassification by the tissue origin (Table 30-3)geographically diverse frequency (Table 30-4)

2. ( 30-3) ( 30-4): 18Ameloblastoma(1) General featuresthe most common clinically significant and potentially lethal odontogenic tumororigin: rests of dental lamina, epithelial lining of an odontogenic cyst, or basal cells of oral mucosa3 different variants: solid/multicystic(92%), unicystic(6%), and peripheral(2%) i) Solid or Multicystic Ameloblastomapatients over a wide age range, with no gender predilectiona painless expansion of the jawslow growth leading to facial disfigurement when untreatedmutilocular radiolucency on radiographresorption of adjacent tooth rootshistologic patterns : follicular; plexiform; acanthomatous; granular cell; desmoplastic; basal cell

(1) : , , 3 : /(92%), (6%), (2%) i) / , : , , , , ,

19i) Solid or Multicystic Ameloblastoma (continued)proliferative capacityrecurrence high number of PCNA-positive cells and previously unoperated ameloblastomasaggressive behavior overexpression of BCL2, BCLX and expression of IL-1, IL-6Treatment and prognosishighly aggressive and curablenumerous treatment recommendatoins: simple enucleation, curettage, resectionInfiltrating feature likely to be recurrent and persistentresection with 1.0cm linear bony margins is recommendedany less aggressive treatment postoperative persistence

i) / () : PCNA- , BCL2, BCLX IL-1, IL-6 : , , 1.0cm

20ii) Unicystic Ameloblastoma- Histologic alterations associated with neoplastic transformation of ameloblastomatous epithelium Histologic changesHyperchromatism of basal cell nuclei of the epithelium lining the cystic cavities.Palisading and polarization of basal cell nuclei of the epithelium lining the cystic cavities. Cytoplasmic vacuolization, particularly of basal cells of cystic linings. ii) - - (1) (2) (3)

21ii) Unicystic Ameloblastoma (continued)Pattern of epithelial proliferation described in dentigerous cysts of the jaw that does not exhibit the histologic criteria for ameloblastoma. It may be treated more conservatively than the solid or multicystic ameloblastoma in many cases.The average age of patients with unicystic ameloblastomas has been reported as 22.1 years.More than 90% are found in mandible(usually in the molar/ramus region).ii) () - . - . - 22.1 - 90%

22ii) Unicystic Ameloblastoma (continued)

Radiograph: unilocular radiolucency, mimicking a dentigerous cyst Three histopathologic variants luminal unicystic ameloblastoma confined to the luminal surface of the cyst consists of a fibrous cyst wall with a lining that consists totally or partially of ameloblastic epithelium. intraluminal unicystic ameloblastoma one or more nodules of ameloblastoma projecting from the cystic lining into the lumen of the cyst mural unicystic ameloblastoma the fibrous wall of the cyst is infiltrated by typical follicular or plexi- form ameloblastoma.

ii) ( ) - : , - 1. - - 2. - 3. -

23ii) Unicystic Ameloblastoma (continued)Treatment and PrognosisOpen a cystic lesion and look for luminal proliferation of tumor Histopathologic examination (This is particularly impor- tant when dealing with large cysts. )Subclassify the variant of unicystic ameloblastoma When confined to the lumen of the cyst with or without intraluminal tumor extension, the enucleation has probably been curative treatment When the cyst wall has been violated by the tumor as in a mural variant of unicystic ameloblastoma, the most appropriate surgical management is quite controversial

ii) ( )- . ( ) , , , .24Luminal or intraluminal variant : enucleation and curettage Recurrence rate : 10-20% following enucleation and curettage When recurrence arise:recurrent unicystic ameloblastoma : more aggressive resection. mural ameloblastoma : more aggressive than the luminal and intraluminal variants owing to the presence of tumor in the cyst wall and therefore closer to the surrounding bone. very large tumors with significant expansion : resection

10-20% .:1. : 2. : . .3. :

25iii) Peripheral Ameloblastoma Most rare variant of the ameloblastoma. Probably arises from rests of dental lamina or the basal epithelial cells of the surface epithelium Shows the same features of the intraosseous form of the tumor Clinically, nonulcerated sessile or pedunculated gingival lesionsMost 50 years of age and typically occur in the mandible Dentigerous cysts can undergo glandular metaplasia

iii) - - - -5 30-40%- .- 50 - .

32iv) Clear Cell Odontogenic Carcinoma Although putative odontogenic origin, histologic similarities to the developing tooth germ are lacking in many instances Differnential diagnosis: metastasis from a distant site, especially the kidney. Chief entity to consider: clear cell variant of renal cell carcinomaGenerally in elderly women, equally in Mx and Mn.iv) - , .-: - -

33v) Malignant Epithelial Odontogenic Ghost Cell Tumor Also known as dentinogenic ghost cell tumor Solid variant of the calcifying odontogenic cyst Both epithelial and ectomesenchymal odontogenic elements are present Only the epithelial component shows cytologic features of malignancy.

v) - - -

343) Ameloblastic fibroma

The epithelial and mesenchymal tissues are both neoplastic.Occur in young patients in the first two decades 70% 0f cases : post. Mn.Radiogaraph: unilocular or multilocular lesion Treatment and Prognosisenucleation and curettage surgery Resection: recurrent lesions

3) - -20 - : - :

354) Ameloblastic Fibro-odontoma Probably represents a hamartoma Only a stage in the development of an odontoma and does not represent a separate entity. Occurs more frequently in the posterior regions of the jaws Commonly asymptomaticWell circumscribed and appear as mixed radiopaque/radiolucent masses.Treatment and PrognosisEnucleation and curettage surgery Recurrence after this approach is very rare

4) -- .- - - /-

365) Odontoma The most frequently occurring odontogenic tumors Hamartomas Two forms Compoundmultiple small toothlike structurespredominantly seen in the anterior maxilla Complexirregular masses of dentin and enamelno anatomic resemblance to a tooth typically seen in the posterior maxilla or mandible Treatment and Prognosissimple enucleation and curettage

5) - -- 1) 2) -

376) Odontogenic Myxoma An uncommon benign neoplasm of the jawsDerived from ectomesenchymeHistologically resembles the dental papilla of the developing tooth Slow growing with a potential for aggressive behaviorHigh recurrence rate after subtherapeutic removal Occur over a wide age range but seem to occur most commonly in the third decade of life The posterior mandible is most common location

6) - - - - - 30 -

386) Odontogenic Myxoma (continued)

Histologically: haphazardly arranged stellate, spindle-shaped, and round cells in an abundant loose myxoid stroma.Radiographically: unilocular or multilocular radiolucency that may displace or cause root resorption of teeth in the area of the tumorPathogenetically: the proliferation and aggressive behavior(related to overexpression of antiapoptotic cytokines BCL2 and BCLX). Treatment and Prognosisresection with 1.0 cm bony linear margins not encapsulated and tend to infiltrate the surrounding bone

6) ( )-, , , -, .-, , BCL2 BCLX - 1cm

397) Calcifying Epithelial Odontogenic Tumor - Also known as the Pindborg tumor - An uncommon lesion ( < 1% of all odontogenic tumors)

7) -Pindborg - ( 1% )

407) Calcifying Epithelial Odontogenic Tumor (continued)

Most patients between 30 and 50 years of age Two-thirds of these neoplasms occur in the mandible A painless slow-growing mass Radiographically: mixed radiopaque/radiolucent lesion (frequently associated with an impacted tooth) Histologically: Discrete islands, strands, or sheets of polyhedral epithelial cells in a fibrous stroma Large areas of amorphous eosinophilic hyalinized (amyloid-like) material Calcifications: develop within the amyloid-like material and form concentric rings, known as Liesegang rings The precise nature of the amyloid-like material is unknown Amyloid-like material: stained with Congo red or thioflavine T. (apple-green)

Treatment and PrognosisPindborg tumor is highly infiltrative and destructive and is capable of aggressive behavior. Recommended to be treated identically to the ameloblastoma and odontogenic myxoma, with 1.0 cm bony linear margins

7) ( )- 30 50 - 2/3 - -, ( )-: , , ( ): Liesegang rings : - Pindborg .1cm , 418) Adenomatoid Odontogenic Tumor Hamartoma Uncommon odontogenic lesion (3 to 7% of all odontogenic tumors)Once believed to be a variant of ameloblastoma and was previously designated adenoameloblastoma Limited to young patients (2/3 of all cases are diagnosed in the second decade)Extremely uncommon (in patients > 30 years)Predilection:anterior region of the jawstwice as often in the maxilla than in the mandible Females are affected about twice as often as males

8) -- ( 3~7%)- - ( 2/3 20 )-30 - 2 2

428) Adenomatoid Odontogenic Tumor (continued)

Small, rarely exceeding 3 cm in diameterA well-circumscribed unilocular radiolucency that involves the crown of an erupted tooth, frequently a canine. Histologically: Well-defined lesion (usually surrounded by a thick fibrous capsule) Central portion of the tumor: essentially solid or varying degrees of cystic change with intraluminal proliferation of tissue. Spindle-shaped epithelial cells that form sheets, strands, or whorled masses of cells in a scant fibrous stromaThe epithelial cells may form rosette-like structures about a central space Tubular or duct-like structures A layer of columnar or cuboidal epithelial cells whose nuclei exhibit reverse polarization

Treatment and PrognosisEnucleation and curettage surgery

) ( )-, 3 - , .- ( ) : , .-

43