Oral Pathology I - Chapter 7: Cysts

Study Notes

Cyst Definition: A pathologic cavity lined by epithelium, containing fluid, semifluid, or gaseous material.
Pseudocyst Definition: A pathologic cavity not lined by epithelium.
Jaw Cysts: More prevalent than other bone cysts due to numerous epithelial rests.
Cyst Components: Composed of a lumen (cavity), epithelial lining, and a wall (capsule).
Cyst Frequency: Radicular cyst > Dentigerous cyst > Odontogenic keratocyst > Residual cyst > Paradental cyst.

True Cysts: Odontogenic and non-odontogenic.
Odontogenic: Originate from tooth-forming tissues. Includes periodontal cysts, dentigerous cysts, Gorlin cysts, and others.
Non-Odontogenic: Originate from other tissues. Examples include dermoid, epidermoid cysts, benign lympho-epithelial cysts, and mucous retention cysts.
Pseudocysts: Extraosseous or soft tissue cysts.
Soft Tissue Cysts: Dermoid cysts, epidermoid cysts, traumatic cysts, aneurysmal cysts, and extravasation cysts.

General Features: Usually radiolucent, though some (like Gorlin cysts) are not.
Shape: Often unilocular (single chamber), though some (like OKC and botryoid cysts) can be multilocular.
Location: Usually intraosseous (within the bone), but some are extraosseous.
Common Features: Painless, slowly-growing, hard swellings that might become painful if infected; later, they may soften and become fluctuant and bluish in appearance.

Mechanism: Inflammation initiates the process, triggering epithelial proliferation of rests of Malassez, and followed by a hydrostatic phase which leads to cyst growth.

Clinical Characteristics: Affects adults aged 20-60, predominantly in mandibular premolars and anterior maxilla (jaw). Usually asymptomatic.
Radiographic Features: Well-defined unilocular radiolucency, with a sclerotic margin, commonly lateral to the tooth root.
Histological Characteristics: Glycogen-rich clear cells within the lining.

Definition: A cyst that forms from the separation of the tooth follicle from the unerupted tooth crown following the formation of the enamel.
Origin: Develops by the accumulation of fluid between the reduced enamel epithelium and the crown of the tooth.

Description: A soft tissue cyst commonly found in conjunction with erupting primary or permanent teeth.
Features: Swelling above visible teeth, and the cyst may be unilateral or bilateral.

Description: Soft tissue analogue of the lateral periodontal cyst, originating from dental lamina rests.
Clinical features: Located in the buccal gingiva (most commonly).
Radiographical features: Unlikely to appear on radiographs.

Description: A keratin filled cyst, with developmental origins from dental lamina remnants.
Clinical features: Presents as small, whitish-yellow papules on the alveolar ridge of newborns, which tend to disappear spontaneously.

Origin: Arises from dental lamina or its remnants, or from enamel organ.
Clinical Characteristics: Common in the second and third decades, with no particular sex predilection
Radiographic Features: Well-defined multilocular radiolucency.
Histological Features: Cystic lining composed of keratinized stratified squamous epithelium, potentially containing ghost cells
Aggressive behaviour

Traumatic Bone Cyst: Resulting from trauma & hemorrhage.
Aneurysmal Bone Cyst: Vascular malformation.
**Static Bone Cyst:**Developmental focal concavity of the mandible's lingual cortex.
Mucous Extravasation Cyst: From ruptured minor salivary gland ducts.
Dermoid Cyst: Formed from totipotent cells, capable of producing derivatives from all three germ layers.
Thyroglossal Tract Cyst: A common developmental cyst in the neck, originating near the foramen cecum and migrating during fetal development.
Epidermoid Cyst: Originating from entrapped ectodermal cells, usually found affecting the skin, but occasionally the oral cavity.

Etiology: Obstruction of salivary gland ducts (e.g., by sialoliths or inflammation).
Clinical Features: Asymptomatic swelling typically located on the upper lip, palate, cheeks, or floor of the mouth.