Cysts of the Jaws and Oral Cavity

Cysts of the Jaws and Oral Cavity

• A cyst is a pathological cavity containing fluid or semi-fluid, not pus. Most cysts are lined wholly or partly by epithelium.
• Key features of jaw cysts include sharply defined radiolucencies with smooth borders, fluid that can be aspirated, slow growth, and rarely large enough to cause a fracture. They may be symptomless unless infected.
• Cysts are categorized as odontogenic or non-odontogenic based on the source of the lining epithelium.
• Odontogenic cysts originate from the tooth-forming organ's epithelial residues, and can be further separated into inflammatory and developmental types, based on their etiology.
• Non-odontogenic cysts are derived from sources other than the tooth-forming organ.

Classification of Cysts of the Jaws

• Epithelial Cysts:

  • Odontogenic Cysts:

    • Inflammatory Cysts: Apical cyst, lateral radicular cyst, residual cyst, paradental cyst.
    • Developmental Cysts: Dentigerous cyst, eruption cyst, odontogenic keratocyst, gingival cyst, lateral periodontal cyst, glandular odontogenic cyst, calcifying odontogenic cyst.

  • Non-Odontogenic Cysts: Nasopalatine duct cyst, naso-labial cyst, globulomaxillary cyst, median cyst.

• Non-Epithelialized Primary Bone Cysts: Solitary bone cyst, aneurysmal bone cyst, Stafne's idiopathic bone cavity.

• Soft Tissue Cysts: Branchial cyst, dermoid cyst, thyroglossal duct cyst, salivary gland cysts.

Relative Frequency of Jaw Cysts

• Radicular (periodontal) cysts: 65-70%
• Dentigerous cysts: 15-18%
• Odontogenic keratocysts: 3-5%
• Nasopalatine cysts: 5-10%
• Lateral periodontal cysts: <1%
• Paradental cysts: <1%

Pathogenesis of Odontogenic Cysts

• Epithelial Rests of Serres: Persisting after dissolution of the dental lamina, give rise to odontogenic keratocysts, developmental lateral periodontal cysts, and gingival cysts.
• Reduced Enamel Epithelium: Derived from the enamel organ, covers the crown of the unerupted tooth, gives rise to dentigerous cysts, eruption cysts, and inflammatory paradental cysts.
• Rests of Malassez: Formed from fragmentation of the epithelial root sheath of Hertwig, source of all radicular cysts.

1- Radicular Apical Cysts

• Commonly associated with non-vital teeth.
• Usually small, discovered during routine radiographic examinations.
• As they enlarge, may cause alveolar bone expansion.
• Pain is seldom a feature unless there's an acute exacerbation, usually seen in any age, but rare in deciduous teeth.
• Can occur in any tooth, although maxillary anterior teeth are involved in 60% and mandibular cysts are usually posterior to the canine.
• Radiographically, they present as round or ovoid radiolucencies at the root apex.

2-Residual Radicular Cysts

• Persist after extraction of the causative tooth.
• Common cause of swelling in older individuals.
• Lining may be thinner with mild inflammation.

3-Lateral Inflammatory Periodontal Cysts

• Form on the side of a non-vital tooth, resulting from the opening of a lateral branch of the root canal
• Distinguish from developmental cysts.

4-Paradental Cysts

• Occasionally result from inflammation around partially erupted teeth, commonly mandibular third molars.
• Typically occur in individuals aged 20-25 years old.
• The affected tooth is usually vital, but shows pericoronitis.
• Histologically, lining is similar to that of radicular cysts with more intense inflammatory infiltrate in the wall.

4-Developmental Odontogenic Cysts

• Dentigerous Cysts: Surround the unerupted tooth's crown. A dilation of the follicle prevents eruption.
• Largest developmental odontogenic cyst.

1-Nasopalatine Canal Cysts

• Most common non-odontogenic cysts.
• Also known as incisive canal cysts or palatine papilla cysts.
• Embryologically arise from remnants of the nasopalatine duct.
• Commonly found in midline of maxilla. Middle-aged adults.
• Usually asymptomatic (unless infected) or discovered on routine exam, showing pseudo-locuation.

2- Nasolabial Cysts

• Rare lesion arising in the upper lip (below ala of nose).
• Likely related to remnants of nasolacrimal duct.
• Clinically slow growing, obliterating the nasolabial fold.
• Symptoms may be bilateral. Most common in females.

3- Globulomaxillary Cysts

• Very rare, occurring between roots of the maxillary lateral incisor and canine teeth.
• Possibly a special type of lateral periodontal cyst.

4-Median Cysts

• Rare
• Arise from epithelial remnants entrapped in the fusion of the lateral palatine shelves, usually during the early embryonic development of the mandible.

1-Solitary Bone Cysts

• Often seen in children and adolescents.
• Commonly seen in the premolar and molar areas of the mandible.
• No definite sex predilection.
• Asymptomatic but frequently found incidentally on X-rays.
• Radiolucency of variable size and irregular outline, often scalloped around and between teeth roots.

2-Aneurysmal Bone Cysts

• Rare in the jaw.
• Usually in the mandible, posterior part.
• Occur in children and young adults.
• Presents with a firm painless swelling.
• Often unilocular or multilocular, expansile radiolucency with ballooned-out appearance, due to cortical expansion.
• Microscopically: non-endothelial-lined blood spaces, cellular fibrous tissue, multinucleated giant cells, traces of old and recent hemorrhage, trabecula of osteoid and woven bone.

3- Stafne's Idiopathic Bone Cavity

• Uncommon developmental anomaly of the mandible.
• Symptomless, often discovered incidentally.
• Radiographically: well-demarcated, round or oval radiolucency located between premolar region and angle of mandible, often beneath inferior dental canal.
• Usually bilateral. Saucer-shaped depression in the lingual aspect of the mandible.

IV- Soft Tissue Cysts

• 1-Branchial Cysts: Rare, deep to or along the anterior border of the sternomastoid muscle near the angle of the mandible; possible epithelial remnants from branchial clefts (embryonic development).
• 2-Dermoid Cysts: Uncommon, arise within the floor of the mouth, midline; often submental or sublingual. Embryonic origin, incomplete fusion of branchial arches.
• 3-Thyroglossal Duct Cysts: Most common developmental neck cyst, arise from thyroglossal duct remnants (during development). May be seen in the neck or midline of the posterior region of the tongue.

5- Palatal Cysts (of neonates)

• Common in neonates.
• Thought to be from proliferations of epithelial rests of Serres.
• Appear as small cysts in palate and referred to as "Bohn's nodules" or "Epstein's pearls".
• Most resolve spontaneously.

6- Calcifying Odontogenic Cysts (Gorlin Cysts)

• Uncommon
• May be grouped with other odontogenic tumors like odontomes or ameloblastomas.
• Usually happens before age 40. Usually found in mandible (75% of cases)
• May be related to inflammatory or trauma.

Explore the types, features, and classifications of cysts found in the jaws and oral cavity. This quiz focuses on understanding the differences between odontogenic and non-odontogenic cysts, as well as the specific types of each category. Test your knowledge on the nature and implications of these dental conditions.