odontogenic keratocyst a developmental cyst

Odontogenic keratocyst is one the aggressive developmental cyst of oral cavity. It's a true cyst .

1. Odontogenic keratocyst Sayyed Jani BDS

2. Introduction: It is a developmental odontogenic cyst which is distinguished by its characteristic histological features, high rate of reoccurrance and aggressive behaviour . Term ‘ odontogenic keratocyst ‘ was frist used by Philipsen in 1956. Pindborg and Hansen in 1963 described the external features of cyst.

3. Pathogenesis: This cyst is derived from (a) Cell rests of Serre (b) Basal layer of oral epithelium (c) liquefaction degeneration of stellate reticulum

4. Demographs : Gender prediction: Males > females Age prediction: 2 nd to 3 rd decade of life Site prediction: Mandible ( ramus region> thrid molar> 2 nd and 1 st molar area ) > Maxilla ( thrid molar area > cuspid region) origin: Developmental odontogenic cyst

5. Types: There are two types of odontogenic keratocyst based on type of keratinization. They are (a) Parakeratinized odontogenic keratocyst (b) orthokeratinized odontogenic keratocyst

6. Clinical features: Pain Soft tissue swelling expansion of bone Drainage Various neurological manifestations like paresthesia of lip or teeth Multiple lesions of okc are seen in children with Naevoid Basal Cell Carcinoma Syndrome. On aspiration we can see straw coloured chessy Material . Maxillary lesion tends to be secondarily infected with greater frequency than mandibular one due to its vicinity to Maxillary sinus.

7. Radiographic features: Seen as unilocular ( 80%) or multilocular ( 20%) radiolucent areas with scalloping of border. Multilocular apperance is due to satellite cyst which may mimic Ameloblastoma . Unilocular associated with impacted tooth may mimic Dentigerous cyst . Little cortical plates expansion is seen Root resorption and tooth displacement is seen Sometimes neovascular bundle is displaced .

8. Histological features: Lining epithelium may be Parakeratinized ( 83%) or orthokeratinized (10%) or both ( 7%) Parakeratinized okc : Lining epithelium is parakeratinized stratified squamous epithelium with 5 to 8 layers of cell Rete pegs are absent Basal layer of cells are palisaded , polarized; shows “Picket fence or Tomb stone appearance” Connective tissue shows satellite cysts or islands of epithelium; collagen fibres ; blood vessels lumen contains straw coloured cheesy fluid with keratin content .

9. Treatment and prognosis: Surgical excision