ODONTOGENIC KERATOCYST Keratocystic odontogenic tumor

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

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

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

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.

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

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)

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

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

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.

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.