A distinctive developmental odontogenic cyst arising from dental lamina remnants.
Most common in the mandible, especially posterior body and ramus.
Typically presents in young adults, often as an asymptomatic radiolucency.
Known for locally aggressive behavior and high recurrence rates.
May occur multifocally in nevoid basal cell carcinoma syndrome (Gorlin syndrome).
Dental lamina remnant → cyst formation → PTCH1 pathway dysregulation → abnormal epithelial turnover → characteristic keratinized lining with satellite cysts
PTCH1 mutations are common in syndromic cases (Gorlin syndrome) and can occur sporadically.
The lining epithelium shows intrinsic high proliferative activity, contributing to recurrence.
Thin, uniform parakeratinized squamous epithelium (usually 6–8 cell layers thick).
Corrugated luminal surface (wavy parakeratin).
Palisaded basal cell layer: tall, hyperchromatic nuclei, often polarized.
Cyst wall is typically fibrous and thin with few inflammatory cells.
Daughter (satellite) cysts or epithelial buds may be present in the wall—important for recurrence.
Inflamed OKC:
Inflammation may obscure classic features; epithelium becomes thicker with loss of palisading—can be a diagnostic pitfall.
Ki-67 may show increased proliferation in epithelial layers (not diagnostic but supportive).
PTCH1 mutations (molecular testing) support diagnosis in syndromic patients but not required.
IHC is otherwise not necessary for routine diagnosis.
Orthokeratinized Odontogenic Cyst (OOC)
Orthokeratin, prominent granular layer, bland basal cells; much lower recurrence.
Dentigerous Cyst
Thin non-keratinizing lining; associated with crown of unerupted tooth; lacks parakeratin and palisading.
Unicystic Ameloblastoma
Palisaded ameloblast-like basal cells, reverse polarity, and stellate-reticulum–like epithelium.
Radicular (Periapical) Cyst
Inflamed lining with arcading squamous hyperplasia; associated with a non-vital tooth.
Lateral Periodontal Cyst
Very thin 1–2 cell–layer lining with focal whorls; along lateral root surface, not crown.