Cysts of the Jaw Notes

Definition of a Cyst

• A pathological body cavity, usually lined by epithelium, containing fluid (gas) or semi-solid substances other than pus.
  • Frequently, but not always, lined by epithelium.

Classification of Cysts

• Intraosseous:
  • Odontogenic (Developmental & Inflammatory)
  • Non-odontogenic (Developmental)
  • Non-epithelium lined bone cysts
• Soft Tissue Cysts

Odontogenic Cysts: Developmental

• Derived from:
  • Dental Lamina (Rests of Serres):
    • Odontogenic Keratocysts
    • Calcifying Odontogenic Cyst
    • Glandular odontogenic Cyst
    • Orthokeratinised odontogenic cyst
    • Lateral Periodontal Cysts
    • Gingival Cysts of Adults / Newborns
  • Reduced Enamel Epithelium:
    • Dentigerous Cyst
    • Eruption cyst

Odontogenic Cysts: Inflammatory

• Derived from:
  • Epithelial Rests of Malassez:
    • Periapical/Radicular Cyst
    • Residual cyst
    • Inflammatory collateral cyst (paradental cyst)

Relative Frequency of Jaw Cysts

• Odontogenic Cysts:
  • Radicular: 65%
  • Dentigerous: 20%
• Non-odontogenic Cysts: ~5%
  • Nasopalatine
• Others (combined): 5%

General Symptoms of Cysts

• Asymptomatic (especially if small)
• Pain/swelling (infected cysts)
• Foul taste (discharge)
• Impacted tooth (Dentigerous cyst)
• Missing tooth (keratocyst)
• Pathological fracture
• Displacement/loosening of teeth
• Discoloration of teeth
• Discomfort under denture(s)

General Signs of Cysts

• Swelling & Jaw Expansion
• Soft Tissue Changes
• Tooth Involvement:
  • Missing Teeth
  • Loss of Vitality
  • Loosening, displacement or malalignment
  • Resorption of teeth (dentigerous/radicular cysts)
• Nerve Involvement
• Evidence of Fluctuance
• Presence of a Sinus
• Signs of Maxillary Sinusitis
• Distortion of the Nostril

Diagnosis of Cysts: Radiography

• Most valuable tool for:
  • Outlining the extent & morphology of the lesion
  • Relationship of the lesion with teeth
  • Relationship of lesion to other anatomical structures
• Techniques:
  • Periapical
  • OPG
  • Occlusal
  • CBCT/CT

Diagnosis of Cysts: Aspiration

• Possible aspirates:
  • Pus
  • Blood
  • Air
  • Straw colored fluid
  • White sludgy fluid
  • No aspirate
• If infection suspected: Culture & Sensitivity

Diagnosis of Cysts: Biochemistry

• Keratocysts: Soluble Protein Estimation >5 g/dl
• Other cysts & cystic tumors: Soluble Protein Estimation < 4g/dl

Diagnosis of Cysts: Biopsy

• Most definitive tool
• Incisional biopsy indicated for:
  • Lesions in the mandibular ramus / angle area
  • Extensive lesions
  • Suspected neoplastic lesion
• Excisional biopsy: Entire lesion removed sent for histology

Radicular Cysts

• Most common jaw cysts (>50%)
• Inflammatory in origin from chronic infection/trauma
• Histology: Stratified squamous epithelium
• More common in males; Located in the anterior maxilla
• Radiographic features: Unilocular, well-defined, corticated
• May cause expansion, mobility, displacement, infection
• Histopathology:
  • Uniform layer of SSE
  • Epithelium desquamates, filling lumen with necrotic debris and protein-rich fluid
  • Fibrous connective tissue wall with mixed inflammatory cell infiltrate
  • May show Rushton bodies (linear arch-shaped calcifications)

Radicular Cyst: Histopathology

• Lumen/wall may contain:
  • Dystrophic calcifications
  • Cholesterol clefts
  • RBC hemosiderin pigmentation

Dental Radicular Cysts: Treatment

• Endodontic treatment
• Extraction
• Apicectomy
• Marsupialisation
• Enucleation

Surgical Enucleation Technique

• Flap and expose bony margins
• Create bony window for access
• Aspiration-decompression
• Dissection – blunt +/- extraction / apicectomy +/- adjunct
• +/- bone grafting / reconstruction plate
• Histology
• Primary closure

Dentigerous Cysts

• ~20% of jaw cysts
• Arise from reduced enamel epithelium; encloses crown at CEJ
• Associated with failure of eruption
• Radiographic features:
  • Unilocular
  • Displacement of teeth
• Histology: Cuboidal or low columnar epithelium

Dentigerous Cyst: Radiography

• Unilocular radiolucent area associated with crown of unerupted tooth
• Large cyst may show pseudo multilocularity (persistence of bone trabeculae)
• Well-defined & often sclerotic border, but infected cyst may show ill-defined borders
• Displacement/resorption of adjacent teeth
• Envelopment of adjacent teeth by cyst

Dentigerous Cyst: Histopathology

• 2-4 layers of cuboidal epithelium
• Flat epithelial – connective tissue interface
• Fibrous wall (loosely arranged loose CT)
• Small islands of inactive-appearing odontogenic epithelial rests may be present.

Dentigerous Cyst: Histopathology (Inflammation)

• Increased collagenisation of CT wall
• Infiltration of chronic inflammatory cells
• Epithelial hyperplasia, development & squamous features of rete ridges

Dentigerous Cysts: Treatment

• Surgical extraction
• Enucleation
• Coronectomy
• Marsupialisation / decompression

Marsupialisation Technique

• Create surgical window for decompression
• Obtain Histology
• Suture cyst lining to mucosa – create fistula
• Pack with ribbon gauze
• Use obturator/modified denture
• Irrigation / Quill
• Surgically simple but lengthy follow up

Eruption Cyst

• Soft tissue analogue of dentigerous cyst
• Develops due to separation of dental follicle from crown of erupting tooth within soft tissues

Odontogenic Keratocysts (OKC)

• Origin: Dental lamina remnants
• Features:
  • Para/ortho keratinised epithelium
  • Fragile capsule/satellite/daughter cysts
  • Rapid growth
  • High recurrence rate
• Radiographic: Multilocular, often in ramus of mandible

Keratocyst: Histopathology

• Thin, friable wall, difficult to enucleate
• Uniform layer of SSE, 6 - 8 cells in thickness
• E - CT interface flat; Inconspicuous rete ridges
• Luminal surface shows parakeratotic epithelium
• Basal layer shows basal palisading
• Satellite Cysts (7 to 26% cases)
• Lumen contains a clear liquid (Transudate of serum, Cheesy material (keratinaceous debris))

Gorlin Goltz Syndrome

• Inherited as an autosomal dominant trait
• Features:
  • Multiple BCC of skin
  • Jaw cysts (Keratocysts)
  • Rib anomalies
  • Vertebral anomalies
  • Intracranial calcifications

Odontogenic Keratocysts: Treatment

• Surgical Enucleation +/- Cryotherapy +/- Carnoy’s solution
• 10-year follow up due to local recurrence (daughter cysts & friable lining)
• Associated with Naevoid basal cell carcinoma syndrome (Gorlin – Goltz)

Lateral Periodontal Cyst & Botryoid Odontogenic Cyst

• Arise from epithelial remnants of dental lamina
• Lateral root surface/between roots of erupted teeth
• BOC multi cystic variant
• Well defined corticated radiolucency's lateral tooth
• Adjacent teeth displaced not resorbed
• 1% odontogenic cysts

Gingival Cyst

• Alveolar mucosa adults and children
• Arise from remnants dental lamina or rest cells of Serres
• Multiple small nodules/painless dome blister
• Not usually evident on radiography
• In adults 0.5% odontogenic cysts

Glandular Odontogenic Cyst

• Rare (0.5% odontogenic cysts); Unique glandular differentiation
• Locally aggressive behaviour
• Arise from remnants of dental lamina
• Unilocular/multilocular/teeth displacement
• Features overlap with those of mucoepidermoid carcinoma

Nasopalatine Duct Cysts

• Arise from Embryonic duct remnants
• >male > 20 to 60 yr
• Round/pear/heart shaped lucency in incisive canal
• Swelling ant midline palate

Solitary Bone Cyst

• Also known as: Haemorrhagic / simple / traumatic bone cyst
• Pseudocyst non-epithelialized; Contains blood-stained fluid/gas
• ~1% intraosseous cysts; commonly in young adults (<20yrs)
• Asymptomatic/Vital teeth/incidental
• Surgical exploration is curative

Stafne's Bone Cavity

• Salivary gland inclusion (lingual defect)
• Developmental; Well-circumscribed lucency below IDN, occupied by lobule of SMG
• Asymptomatic

Signs and Symptoms: Benign vs. Suspicious for Malignancy

• Benign:
  • Usually slow onset
  • Swelling
  • Regular Corticated outline
  • Tenderness
  • Slow-growing
• Suspicious Malignancy:
  • Rapid growth
  • Resorption teeth
  • Pain
  • Irregular erosive outline