Orofacial Cysts PDF

OROFACIAL CYSTS Cyst: is a pathological cavity containg fluid, semifluid, or gas, which is lined by epithelium and surrounded by fibrous capsule. Cyst Pathological Cavity Content Lining Arising from a...

OROFACIAL CYSTS Cyst: is a pathological cavity containg fluid, semifluid, or gas, which is lined by epithelium and surrounded by fibrous capsule. Cyst Pathological Cavity Content Lining Arising from a Arising from a Arising from a pathological process pathological pathological either developmenta Or inflamatory process process either developmenta either developmenta Or inflamatory Or inflamatory TOOTH DEVELOPMENT Teeth are formed by tissued originated from the ectoderm and mesoderm Ectomesenchymal cells migrate from the neural crest to the jaws and settle in areas where teeth are to be formed Stages: A. Growth a) Initiation (Bud stage) b) Proliferation (Cap stage) c) Histodifferentiation (Bell stage) d) Morphodifferentiation (Advanced bell stage) e) Apposition B. Calcification C. Eruption D. Attrition 1. Some progenitor cells remain after tooth development, including: I. Dental lamina in the gingiva → Epithelial rests of Serres II. Hertwig’s epithelial root sheath → Epithelial rests of Malassez III. Reduced enamel epithelium 2. Those can turn into Pathological process and then into cyst. 1 of 17  Cyst Inflammatory Developmental *More common Unknown cause; some caused by specific gene mutations Examples: 1. Periapical radicular cyst 2. Residual periapical radicular cyst Examples: 3. Buccal bifurcation cyst 1. Dentigerous cyst 2. Eruption cyst 3. Odontogenic keratocyst OKC 4. Orthokeratinized odontogenic cyst 5. Gingival cyst of the newborn 6. Gingival cyst of the adult 7. Lateral periodontal cyst 8. Calcifying odontogenic cyst 9. Glandular odontogenic cyst Modes of growth: 1. Hydrostatic Almost all cysts Sources of pressure: 1. Poor lymphatic drainage 2. Semi-permable membrane property of the wall and linning 3. Lumen content of degraded inflammatory protiens and dead linning cells Osmotic pressure → Slow expansion and enlargment (faster in children.Why?) → Bone resorption → Pushes periosteum outward 2. Growth of the wall Less common, Primarly in odontogenic keratocyst Epithellial linning has high mitotic rate + Lumen filled with keratin (resistent to degredation + insoluable) → Osmotic pressure Cyst wall enlarges by growing, budding, and insinuating finger-like processes, or developing outpouchings, extending to adjacent wall Path of least resistance Clinical presentation of the cyst: - Asymptomatic - Painless expansion - Abscess - Discoloration - Effect on teeth (Tipping, Displacment, Resorption, No effect on tooth vitality) 2 of 17  Radiographic features of cysts: A. Sharply defined—> Mostly evenly radiolucent B. Smooth rounded outline Cortication: A distinct white line around the edge of a lesion, as a result of surrounding bone forming a reactive thin cortical or sclerotic layer around any cyst that grows slowly C. Unilocular (one cavity) D. Multilocular (multiple cavities) Scalloped outline Septa dividing the locules from one another RADIOGRAPHIC MIMICKERS Anatomical Structures Giant Cell Lesions Pseudocyst Odontogenic Tumors Large Periapical Granulomas Cherubism Odontogenic cysts are either 1. Cysts of the Jaws : 2. Cysts of the Soft Tissues : a. Radicular cyst a. Eruption cyst b. Paradental cyst b. Gingival cyst of the newborn c. Buccal bifurcation cyst c. Gingival cyst of the adult d. Dentigerous cyst e. Odontogenic keratocyst f. Orthokeratinized odontogenic cyst g. Lateral periodontal cyst h. Calcifying odontogenic cyst i. Glandular odontogenic cyst 1. ODONTOGENIC CYSTS OF THE JAWS A. RADICULAR CYST (Periapical Cyst / Apical Periodontal Cyst - Non-vital Tooth —> Periapical Inflammation (periapical granuloma) —Epithelial Proliferation of the Remnants of the Hertwig’s Root Sheath (Rests of Malassez) Variants 1) Periapical / Apical Periodontal Cyst → Around the apex of tooth 2) Lateral Radicular Cyst → Along the lateral aspect of the root 3) Residual Radicular Cyst → At the site of previously extracted Clinical presentation: o The most common jaw cyst o Always associated with a non-vital tooth o Usually asymptomatic; unless becomes infected or large Treatment options: Root canal treatment Radiographic features: Periapical surgery o Well defined, unilocular, evenly radiolucent lesion Tooth extraction and apical curettage o Associated with a non-vital tooth + Micro. exam Microscopic appearance: o Cystic cavity lined by hyerplastic non- keratinzed stratified squamous epithelium with thick, inflamed fibrous capsule; cholesterol clefts maybe seen 3 of 17 Inflammatory collateral cyst (Paradental & Buccal bifurcation) Rare inflammatory odontogenic cysts adjacent to the cervical area or furcation of molars Poorly understood In both, the associated tooth is vital, but typically shows pericornitis or gingival inflammation Examples: B. Paradental cyst Along the distal or buccal aspect of a partially erupted lower 3rd molar affected w/ pericoronitis When large → Tip the roots lingual, and the crown buccally C. Buccal Bifurcation cyst Found along the buccal aspect of an erupting mandibular 1st or 2nd molar in children, also called “mandibular buccal infected cyst” Miroscopic Appearance: Similar to radicular cyst Treatment: Enucleation of cyst +/- extraction of the involved tooth ============= D. DENTIGROUS CYST (Follicular Cyst) Pathogenesis Developmental fluid accumulation between the reduced enamel epithelium and the crown of an unerupted tooth. (Leading to… Separation of the reduced enamel epithelium from the enamel ( Leading to…. Follicle expansion Clinical presentation: The 2nd most common odontogenic cyst The most common developmental odontogenic cyst Always associated with an unerupted tooth attached at its neck portion, i.e., attached at the CEJ (mostly impacted 3rd molars) Radiographic features: Well-defined, unilocular radiolucency, surrounding the crown of an unerupted tooth Large lesions → Expansion, displacement of the tooth, or resorption of adjacent teeth Microscopic appearance: Cystic cavity lined by a thin layer of cuboidal or stratified squamous epithelium about 2 to 3 layers thick; may include scattered mucous cells; may be hyperplastic if secondarily inflamed Dense or loose fibrous wall; typically, no inflammation Treatment options: Surgical enucleation +/- removal of the associated tooth OR +/- coronectomy (if roots are close to the mandibular nerve) OR +/- orthodontic-assisted tooth eruption (if the tooth is salvageable) Marsupialization for large lesions Prognosis - Pathologic fracture with large lesions Excellent; do not recur after treatment Rare complications: - May undergo neoplastic transformation: a. Ameloblastoma b. Rarely squamous cell carcinoma or. intraosseous mucoepidermoid carcinoma may 4 of 17 arise from dentigerous cyst lining E. ODONTOGENIC KERATOCYST (OKC /Keratocystic Odontogenic Tumor) Origin: Epithelial Rests of Serres Clinical presentation: The 2nd most common developmental odontogenic cyst The 3rd most common odontogenic cyst Has a more aggressive behavior than other odontogenic cysts More in the posterior mandible, 3rd molar & ramus area Expands through bone; Grows extensively through the medullary spaces of bone Causes minimal cortical expansion Remains clinically unnoticed until it is too large Radiographic features: Multilocular or unilocular radiolucency (Often multilocular “soap- bubble” appearance) 30% associated with an impacted tooth Microscopic appearance: Thin and fragial cyst wall; often difficult to enucleate from the bone in one piece Often filled with a thick cheesy material (keratin debris) Lining epithelium is parakeratinized stratified squamous and shows basal palisading 6-8 cell layers thickness Cyst wall may contain daughter or satellite cysts Treatment options: Surgical enucleation and curettage: +/- peripheral ostectomy, +/- chemical cauterization, or +/- cryotherapy Marsupialization for Large lesions Long-term follow-up is mandatory; high recurrence Q: What Syndrome is associated with multiple OKC? (4) - Nevoid Basal Cell Carcinoma Syndrome - Basal Cell Naevus Syndrome - Gorlin’s Syndrome - Gorlin-Goltz Syndrome NEVOID BASAL CELL CARCINOMA SYNDROME Autosomal-dominant condition Mutation of PATCH (PTCH) tumor suppressor gene on chromosome 9 Features: 1. Multiple odontogenic kerato-cysts 2. Multiple nevoid basal cell carcinomas 3. Palmar/plantar pits 4. Bifid ribs 5. Calcification of the falx cerebri 5 of 17 F. ORTHOKERATINZED ODONTOGENIC CYST Clinical presentation: Rare; less common than OKC, Behave like a DC; 70% associated with impacted tooth; much less aggressive than OKC Low recurrence rate Not associated with nevoid basal cell carcinoma syndrome Radiographic features: Unilocular radiolucency, associated with impacted tooth Microscopic appearance: A cystic cavity lined by ortho-keratinized stratified squamous epithelium Treatment: Enucleation G. LATERAL PERIODONTAL CYST Origin: Rests of dental lamina (Epithelial Rests of Serres) Clinical presentation: Uncommon developmental odontogenic cyst Forms in the PDL besides the mid portion of the root Adjacent teeth are vital Often symptomless (Asymptomatic) Adults Radiographic features: Small, well-demarcated, unilocular radiolucency Usually between the roots of two adjacent teeth In the premolar-canine regions (80% in the mandibular canine-premolar region) Microscopic appearance: Cystic cavity lined by a thin (1-3 layer thick) stratified squamous or cuboidal epithelium with focal/rounded thickenings/plaques/epithelial nodules (glycogen-filled clear cells) Dense fibrous wall Treatment: Enucleation; rare recurrence BOTRYOID ODONTOGENIC CYST (Rare polycystic variant of lateral periodontal cyst) Radiographic features: o Multilocular radiolucency (“cluster of grapes”) o Larger than lateral periodontal cyst and can expand bone Microscopic appearance: Similar to Lateral periodontal cyst Treatment: Has tendancy to reocur after enucleation 6 of 17 H. CALCIFYING ODONTOGENIC CYST COC / Gorlin’s Cyst / Calcifying Cystic Odontogenic Tumor Clinical presentation: An uncommon developmental odontogenic cyst Anterior to the first molar in the maxilla or mandible Often causes bony expansion Radiographic features: A well-demarcated radiolucency Often with multiple small, radiopaque, calcified foci 33% found around the crown of an unerupted tooth Microscopic appearance: A cystic cavity lined by odontogenic epithelium Ameloblast-like basal cells: Stellate reticulum-like cells in the upper layers Ghost cells (swollen keratinized cells with shadow of nucleus) Dystrophic calcification Treatment options: Enucleation; few recurrences I. GLANDULAR ODONTOGENIC CYST Sialo-Odontogenic Cyst Clinical presentation: - A rare developmental odontogenic cyst - Adults - Majority in the mandible anterior to molars - Tends to be aggressive and may recur following curettage; may be locally destructive May attain large size Cause bony expansion May cross the midline Displace or resorb teeth Radiographic features: - Unilocular or multilocular radiolucency Microscopic appearance: - Cystic cavity lined by a thin layer of stratified squamous epithelium with glandular features: Duct-like spaces Scattered mucous cells Superficial cuboidal or columnar cells +/- cilia Treatment: Small → Enucleation with curettage Large → Surgical excision 7 of 17 ODONTOGENIC CYSTS OF THE SOFT TISSUES A. ERUPTION CYST (Eruption Hematoma) The soft tissue variant of dentigerous cyst, surrounding the crown of a tooth that has erupted through the bone, but not the soft tissue Clinical presentation: Children Small fluctuant swelling on the alveolar ridge Translucent or blue ('eruption hematoma’) An erupting tooth on radiograph Treatment: o None; rupture spontaneously o Can un-roof cyst to facilitate eruption B. Gingival Cyst: Here’s the text with proper spacing: 1. ADULT The soft-tissue variant of lateral periodontal cyst Clinical presentation: - Adults - Facial gingiva of the mandibular canine-premolar area - Small, dome-shaped, translucent, fluctuant swelling Treatment: Surgical removal; no recurrence 2. NEWBORN Multiple small, nodular, keratin-filled, cystic lesions seen along the alveolar ridge of newborns or young infants Origin:** Odontogenic origin; remnants of dental lamina Clinical presentation: - Newborns or infants - Multiple, small, discrete, white nodules on the alveolar ridge Treatment: None required; rupture spontaneously within days 8 of 17