Odontogenic Keratocyst (OKC / KCOT)
The OKC is a developmental odontogenic cyst notable for its aggressive behaviour and high recurrence. It grows in an antero-posterior direction along the marrow spaces with relatively little bony expansion.
Histopathology (high-yield)
- Parakeratinized stratified squamous epithelium (NOT orthokeratinized).
- Uniform thickness (6–10 cells), with a corrugated/wavy luminal surface.
- Palisaded, hyperchromatic basal cell layer ("tombstone/picket-fence").
- Friable, often separated epithelium; satellite (daughter) cysts in the wall → recurrence.
Clinical & Radiographic
Posterior mandible most common. Well-defined uni- or multilocular radiolucency. Multiple OKCs → think Gorlin–Goltz (nevoid basal cell carcinoma) syndrome.
Treatment
Enucleation with peripheral ostectomy, Carnoy's solution, or marsupialization for large lesions. High recurrence demands long-term follow-up.
Exam Tips ⭐
Parakeratinized + palisaded basal layer + satellite cysts + high recurrence = OKC. Orthokeratinized odontogenic cyst is a separate, less aggressive entity with low recurrence.