1. ODONTOGENIC
KERATOCYST
Keratocystic odontogenic tumor

2. Keratocystic odontogenic tumor
A developmental odontogenic cyst
arises from cell rests of the dental lamina.
a different growth mechanism and biologic behavior
their growth …………..unknown factors inherent in the epithelium itself
or enzymatic activity in the fibrous wall.
Several investigators suggest that odontogenic keratocysts be regarded as benign cystic neoplasms rather than cysts.
Keratocystic odontogenic tumor

3. Clinical Features 3% to 11% of all odontogenic cysts.
60% of all cases are diagnosed in people between 10 and 40 years of age.
a slight male predilection.
60% to 80% of cases, in mandible
the posterior body and ascending ramus

4. Small odontogenic keratocysts are usually asymptomatic
Larger odontogenic keratocysts may be associated with pain, swelling, or drainage
Some extremely large cysts, however, may cause no symptoms.
tend to grow in an anteroposterior direction within the medullary cavity of the bone without causing obvious bone expansion.
(This featuremay be useful in differential clinical and radiographic diagnosis).
Multiple odontogenic keratocysts
Evaluation for the nevoid basal cell carcinoma(Gorlin) syndrome

5. Radiographic Features
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(25% to 40% of cases)
Resorption of the roots of erupted teeth adjacent to odontogenic keratocysts is
less common than dentigerous and radicular cysts.

6. may simulate radiographic findings of
dentigerous cyst (from dental laminarests near an unerupted tooth and has grown to envelop the unerupted tooth)
radicular cyst
residual cyst
lateral periodontal cyst
globulomaxillary cyst
nasopalatine duct cysts(Usually> 70 yrs)
Rare examples of peripheral odontogenic keratocyst

7. Histopathologic Features
a thin, friable wall (often difficult to enucleate from the bone in one piece)
The cystic lumen( may contain a clear liquid that is similar to a transudate of serum, or
a cheesy material)

8. parakeratotic epithelial cells, with corrugated appearance
a uniform layer of stratified squamous epithelium, usually 6 to 8 cells in thickness
a characteristic palisaded layer of hyperchromatic cuboidal or columnar basal cells
fibrous wall is essentially devoid of any inflammatory infiltrate.
The epithelium and connective tissue interface is usually flat

10. the fibrous wall
cords of odontogenic epithelium
Small satellite cysts
islands of odontogenic epithelium

11. The characteristic microscopic features have been lost in the central area of this portion of the cystic lining because of the heavy chronic inflammatory cell infiltrate.

12. Treatment and Prognosis
But often tend to recur after treatment (5% to 62%) more often in mandibular odontogenic keratocysts.
chemical cauterization ……………………Carnoy's solution after cyst removal.
Long-term clinical and radiographic follow-up
Many surgeons recommend peripheral ostectomy of the bony cavity with a bone bur
Complete removal of the cyst in one piece is often difficult
Intraluminal injection of Carnoy's solution
the propensity for an odontogenic keratocyst to undergo malignant alteration is no greater and is possibly less than that for other types of odontogenic cysts.