Histologic or Microscopic Features of Odontogenic Keratocyst

It is a developmental Odontogenic Cyst that has characteristic histological features and high rate of recurrence. Initially these lesions are asymptomatic and do not produce any symptoms until the size of the lesion increases and overlap on the adjacent structures. Symptoms of Odontogenic Keratocyst includes Swelling of Jaw, Displacement of Teeth, Pain if Secondarily infected and Pathologic fracture in later stages.

Histopathology of Odontogenic Keratocyst (OKC):

• Lining Epithelium of OKC is characterized by regular parakeratinized stratified squamous epithelium
• The Parakeratinized stratified squamous epithelium is 5-8 cell layers in thickness
• Rete pegs are absent in this epithelium
• Basal cell layer of epithelium is quite distinct with columnar cells which are having a palisading arrangement of nuclei with polarization (nuclei of all cells are away from the basement membrane) which is described as “Tombstone” or “Picket fence” appearance
• The Superficial para keratin layer shows characteristic corrugations. Epithelium may show infolding into the connective tissue capsule and may be separated from capsule in some areas.
• Connective Tissue capsule comprises mainly of parallerly arranged collagen fibers with few cells and blood vessels.
• Satellite Cysts or Proliferating Odontogenic Cell rests may be present in the capsule.
• Cystic lumen contains fluid with low protein level.

 Characteristic Features or Important Features of OKC:

1. Keratinizing lining Epithelium of 5-8 cell layers thick
2. “Tombstone or Picket Fence” appearance of Basal Cells
3. Corrugated parakeratin layer
4. Satellite cysts in Cystic Capsule

Odontogenic Keratocyst treatment involves removing the Cyst using Enucleation or Marsupilisation of the Cyst depending on the size of the lesion. With OKC the most common problem is the recurrence, which is estimated to be around 30% recurrence rate. Most patients who have undergone treatment are expected to get back the lesion within 5 years and in some cases it is seen up to 10 years.

Recurrence is seen due to Satellite Cysts which might have been left out during treatment and in some cases an entirely new cyst is seen from the lamina rests.