Non-Odontogenic Cysts Quiz

Non-Odontogenic Cysts

• These cysts are derived from ectodermal remnants, lacking the potential to form teeth.
• Examples include nasopalatine duct cyst (incisive duct cyst) and nasolabial cyst.

Nasopalatine Duct Cyst (Incisive Duct Cyst)

• Develops from epithelial remnants of the nasopalatine duct in the embryo.
• It's the most common cyst in this group.
• More prevalent in the 5th decade.
• An incisive papilla cyst develops without bone involvement.
• It exhibits a radiolucent area between central tooth roots, appearing round or oval (sometimes heart-shaped).
• The foramen incisivum (6mm widest diameter) can be confused with a small cyst.
• Symptoms typically include a lack of large dimensions, posterior mucosal swelling of central teeth, and vital teeth.
• A sense of a salty taste is sometimes observed.

Nasolabial Cyst (Nasal-Alveolar Cyst)

• Thought to originate from epithelial remnants of the medial and lateral nasal extensions or the nasolacrimal duct.
• It's a soft tissue cyst, not always apparent on radiographs, sometimes visible as a depression in the bone.
• Common age range is 40-60 years old and occasionally bilateral.

Inflammatory Cysts

• These cysts are categorized as inflammatory and odontogenic.
• Examples include radicular cysts (apical and lateral) and residual cysts.

Radicular Cyst

• Develops in the apical or lateral area of non-vital teeth's roots.
• Includes Malassez epithelial remnants.
• Factors driving cyst development include epithelium proliferation, fluid hydrostatic pressure and surrounding bone resorption (prostoglandinII-I).
• Common amongst age groups between 20 and 60 years old with a male/female ratio of 2:1.
• Frequently observed in the maxilla (3/1) or mandible (1/1).
• Occurs in anterior and posterior regions.
• Typically asymptomatic, presenting symptoms only during infection.

Radicular Cyst - Radiology

• Appears as a round radiolucency at the tooth apex with a fine radiopaque border.
• Small lesions can be indistinguishable from periapical granulomas.
• Root resorption is possible in large cysts.

Radicular Cyst - Differential Diagnosis

• Periapical granuloma
• Periapical scar
• Periapical cemento-osseous dysplasia

Radicular Cyst - Histology

• Lined with multilayered squamous epithelium.
• Walls contain hyperplastic connective tissue with multiple blood vessels.
• Includes PMN leucocytes, lymphocytes, plasma cells, and Russell bodies.
• Cyst fluid might contain cholesterol crystals.

Radicular Cyst - Treatment

• Small cysts and anterior teeth treatments involve apical resection and enucleation.
• Large cysts are better treated with tooth extraction followed by enucleation, with emphasis on complete removal to prevent residual cysts.

Collateral Inflammatory Cyst

• A subset of inflammatory cysts excluding radicular cysts.
• "Paradental cysts" are found among younger people (under 20).
• Buccal bifurcation cysts are collateral inflammatory cysts found on the buccal surface of first and second molars.

Residual Cysts

• A cyst remaining at the site of a previously extracted tooth.
• Potential differential diagnoses include haemangioma, unicystic ameloblastoma, adenomatoid odontogenic tumour, and neurilemmoma.
• Treated by enucleation.

Epithelial Jaw Cysts (Pseudocysts/False Cysts)

• Classified as solitary bone cysts (traumatic bone cysts, simple bone cysts, hemorrhagic bone cysts), Stafne bone cysts, and aneurysmal bone cysts.

Traumatic Bone Cysts

• Though trauma is suspected, the precise cause isn't known.
• It involves a level of trauma below the threshold for fractures.
• Normally painless and asymptomatic.
• Aspiration reveals air.
• A radiolucent area between the roots is observed, and there's no tooth root resorption.
• Treatment involves ventilation.
• It's not a true cyst but mimics one due to haemorrhage accumulation and clot organization after trauma, causing a cavity.

Soft Tissue Cysts Around the Mouth

• Includes eruption, gingival, nasolabial cysts, dermoid cysts, thyroglossal cysts, and branchial cysts, and salivary gland cysts.

Dermoid Cysts

• Embryonic skin (epidermis or dermis) elements are positioned between tissues.
• The cyst wall consists of skin tissue folds and is filled with yellowish, sludge-like material.
• Usually located on the cheek or under the chin (between the genioglossus, geniohyoid, and mylohyoid muscles).
• Typically characterized by slow growth and unilateral occurrence, sometimes appearing in patients over 40.
• In children, it can be easily detected by a painless, movable, rubbery swelling inside the mouth and under the jaw.
• Treatment involves extirpation through extraoral incisions.

Thyroglossal Duct Cysts and Fistulas

• Originates from remnants of the ductus thyroglossus which forms part of the thyroid gland.
• Located in the midline of the neck, between the foramen cecum and the sternum (occasionally off-center).
• Typically present at birth as a single mass.
• May move during swallowing and often causes difficulties in swallowing when the cyst is closely associated with the tongue.
• Possible infection and pain.
• Frequent treatment method is surgical excision of the cyst and fistula and removal of part of the hyoid bone to prevent recurrence.
• Thyroid tissue is maintained during surgery to prevent myxoedema.

Branchial Cysts

• Arises from branchial arch epithelium during embryonic development.
• Located under the angle of the jaw and along the sternocleidomastoid muscle.
• May cause a soft, fluctuating swelling.
• Can become infected after an upper respiratory tract infection, developing pain.
• Typically requires surgical treatment.

Salivary Gland Cysts: Mucous Extravasation Cysts

• Includes mucocele/ranula subtypes.
• Result from minor salivary gland duct ruptures.
• No epithelial lining.
• Located on the lower lip, tongue, or cheek.
• Primarily found in children and younger adults.
• Treatment depends on the specific cyst.

Salivary Gland Cysts: Mucous Retention Cysts

• Characterized by an epithelial lining (true cyst).
• Develops from duct dilation, caused by obstruction or cystic changes in the duct epithelium.
• Impacts minor and major salivary gland ducts.
• Predominantly occurs in adults.
• Less common than mucoceles.
• Treated by cyst removal.

Cyst Treatment: Enucleation

• Advantages include microscopic examination of the entire cyst and no postoperative monitoring required.
• Disadvantages include clot infection in the cavity, recurrence if complete removal is not performed, and potential trauma to neighboring structures (teeth, blood vessels, nerves, sinus, or jaw).

Cyst Treatment: Marsupialization

• Combining cyst and oral cavity through a window opening along the cyst's equator.
• Cyst epithelium is not completely removed.
• Indications include situations needing to preserve neighboring tissues, large cysts, elderly patients, complications from jaw fractures or anatomical structures, and surgical transport difficulties.
• Disadvantages include continuous physician visits, inability to examine the complete cyst microscopically, and needing a second surgical procedure for keratocysts.

Cyst Treatment: Fenestration

• Initiates bone regeneration by opening and maintaining a cyst-opening to reduce cyst size.
• Non-definitive auxiliary treatment.
• Preserves neighboring teeth and mandibular canals via new bone formation.
• Requires a second surgical procedure.

Follow-up After Cyst Surgery

• Post-operative examination, typically after 6 months or until complete bone regeneration, is needed for enucleation surgeries.
• Keratocysts require a 6-to-10-year follow-up.
• Fixed prostheses should be delayed until confirmed bone healing.
• Need for long-term patient follow-up should be discussed.