Odontogenic Keratocyst

Etiology • A benign, aggressive developmental odontogenic cyst; may be
associated with mutation of PTCH tumor suppressor gene
Clinical Presentation • 5 to 15% of odontogenic cysts • Usually occurs sporadically as an isolated finding • Approximately 5% are associated with nevoid basal cell
carcinoma. • 5% of patients have multiple odontogenic keratocysts (OKCs)
and no syndrome

Radiographic Findings • Can occur in any area of maxilla or mandible • Rarely may arise in gingival soft tissue only (peripheral) • Mandible is preferred site in 65 to 78% of cases • Often (40%) seen in a dentigerous relationship • Discrete radiolucency, usually in relation to teeth (apical, lateral
radicular, pericoronal to impacted tooth) • May be unilocular to multilocular
Microscopic Findings • Thin, parakeratinized epithelial lining (6–10 cells thick) • Wavy, corrugated surface configuration • Prominent, palisaded, cuboidal to low-columnar basal cell layer • Basal layer “budding” into fibrous stroma is seen occasionally • Satellite or daughter cyst formation noted frequently
Diagnosis • Radiographic features • Microscopic findings
Differential Diagnosis • Odontogenic cysts: dentigerous, radicular, lateral periodontal,
or glandular odontogenic • Nonodontogenic cyst: nasopalatine duct • Odontogenic tumors: ameloblastoma, myxoma

• Giant cell granuloma • Central mucoepidermoid carcinoma
Treatment • Excision with curettage of bony confines
Prognosis • The recurrence rate varies from 10 to 30% (solitary OKCs). • Recurrence rates are greatest in patients with a syndrome.