Odontogenic Cysts and Tumors

Odontogenic Cysts

• A list of 13 types of odontogenic cysts

Odontogenic Tumors

• Tumors of odontogenic mesenchyme: central odontogenic fibroma, peripheral odontogenic fibroma, granular cell odontogenic tumor, odontogenic myxoma, cementoblastoma

Dentigerous Cyst

• AKA follicular cyst
• Second most common odontogenic cyst
• Encloses the crown of an unerupted tooth at the cemento-enamel junction
• Histogenic source is proliferation of enamel organ remnant or reduced enamel epithelium
• Predilection sites are third molars and maxillary canines
• More common in males during the second to third decade
• Most common indication is delayed eruption
• Asymptomatic
• Size ranges from millimeters to centimeters, causing facial asymmetry and compromising jawbone integrity
• Exhibits a well-circumscribed unilocular radiolucency around the crown of an impacted tooth
• Fibrous connective tissue wall with nonkeratinized stratified squamous epithelium lining
• Treatment involves enucleation and removal of the associated tooth, sometimes with orthodontic treatment
• Large cysts are initially treated with marsupialization and later excision
• Complications include transformation into ameloblastoma or carcinoma

Paradental Cyst

• AKA buccal bifurcation cyst
• Variant of dentigerous cysts
• Found at the bifurcation of molar teeth
• Originally seen along the buccal root surface of partially erupted mandibular third molars, now found with fully erupted molars
• Radiographically, shows well-circumscribed radiolucencies in the buccal furcation area

Eruption Cyst

• AKA eruption hematoma
• Soft tissue analogue of the dentigerous cyst
• Develops around the crown of an erupting tooth within the soft tissues overlying the alveolar bone
• Results from fluid accumulation in the follicular space of an erupting tooth
• Commonly seen in the mandibular molar region
• Presents as a soft, smooth-surfaced, reddish-pinkish or bluish-black, translucent, fluctuant swelling on the alveolar ridge
• Can appear purplish or brown if traumatized
• Epithelial lining made of reduced enamel epithelium
• No treatment is required because the cyst ruptures on its own

Primordial Cyst

• Controversial and confusing
• Originates from cystic degeneration of the enamel organ epithelium before dental hard tissue development, taking the place of a tooth
• The term was widely accepted in the mid 1950's
• Referred to as the preferred term in 1972 by the WHO, originally
• In 1992 the WHO preferred the designation Odontogenic Keratocyst

Odontogenic Keratocyst

• Current concept deems these cystic tumours and rejects them being developmental cysts
• Arises from remnants of dental lamina in the mandible and maxilla
• Relatively common jaw cysts
• Peaks in the second and third decades
• 2:1 mandible to maxilla ratio
• In the jaw, it is found in the posterior of the body and ramus, and third molar area
• Asymptomatic when small
• Larger cysts can cause pain, swelling, or drainage, and can grow without obviously expanding the bone
• Well-demarcated area of radiolucency with a scalloped, radiopaque margin
• May be unilocular or multilocular
• Can expand buccally
• The thin lining of epithelium is parakeratinized
• Basal layer contains palisaded cells with uniform nuclei that stain intensely
• May contain keratin debris or serum transudate
• Treated by surgical excision with peripheral osseous curettage or ostectomy
• Can remove pressure surgically or use marsupialization to permit cyst shrinkage and then enucleate
• Prone to recurrence
• Stratified squamous epithelium with an orthokeratotic surface and keratohyaline granules

Orthokeratinized Odontogenic Cyst

• Refers to how the odontogenic cyst looks under a microscope, and is not a particular type of cyst
• In the past, it was considered the orthokeratinized version of odontogenic keratocyst, but looked and behaved differently
• 7%-17% of keratinizing jaw cysts
• Usually apparent in young adults
• Male-to-female ratio of 2:1
• At a ratio of 3:1, mandible is more likely than maxilla to be impacted
• Mandibular third molar frequently implicated
• Size ranges from less than 1 cm to greater than 7 cm
• Only 2/3 presented clinically and radiographically as dentigerous cysts
• Enucleation with curettage
• Rare recurrence (2%)
• A greater risk of malignant transformation

Nevoid Basal Cell Carcinoma Syndrome

• AKA Gorlin syndrome
• Autosomal dominant condition with high penetrance and variable expressivity caused by mutations in PTCH gene on chromosome 9q22.3-q31
• 35%-50% of affected patients have new mutations
• OKCs are one of the most common clinical features , which can lead to early diagnosis
• The prevalence can range from 1 in 19,000 to 1 in 256,000
• OKCs leads to early diagnosis
• Variability exists in components of nevoid basal cell carcinoma syndrome-no single component is present in every single patient
• Frontal and temporoparietal bossing causes the head to be greater than 60cm
• Eyes are widely separated, which is also known as ocular hypertelorism
• Mild mandibular prognathism
• Basal cell carcinomas happen after puberty, or in the second and third decades of life, or in young children
• Can appear on skin unexposed to sunlight
• Punctate lesions or depressed area on the palms or soles
• Multiple OKCs are associated with the crowns of unerupted teeth, and mimic dentigerous cysts
• Anomalies are minor or not life threatening
• Prognosis depends on how basal cell tumors behave, which are triggered by UV radiation from sunlight or radiation therapy
• Jaw cysts are treated as isolated OKCs

Gingival Cyst of the Newborn

• AKA alveolar cyst of the newborn
• Superficial, keratin-filled
• Arise from remnants of the dental lamina
• Common: 50% of all newborns
• Small, multiple whitish papules on the mucosa overlying the alveolar processes of neonates
• 2 to 3 mm in diameter
• More prevalent in the maxilla than mandible
• Thin, flattened epithelial lining with a parakeratotic luminal surface
• Lumen contains keratinaceous debris
• No treatment needed, as it resolves on its own when they rupture

Gingival Cyst of the Adult

• Uncommon lesion
• Soft tissue counterpart of the lateral periodontal cyst
• Derived from rests of the dental lamina
• Site of predilection is mandibular canine and premolar
• When in the maxillary bone, its in the incisor, canine and premolar areas
• Facial gingiva or alveolar mucosa
• 5th-6th decade
• Usually under 0.5cm, and painless and domelike
• Exhibits thin lining with or without cells that contain clear cells
• Excised with a scalpel