odotogenic.txt

• Background:
• separation of the follicle from around the crown of an unerupted tooth
• Most common developmental cyst (20%)
• encloses crown of an unerupted tooth
• attached to the tooth at the CEJ
• Fluid accumulation between the reduced enamel epithelium and the tooth crown
• may develop around the crown of an unerupted permanent tooth as a result of periapical inflammation from an overlying primary tooth
• Paradental cyst→ sometimes this term is applied to this lesion
• Clinical & Radiographic features:
• any unerupted tooth, but most involve mandibular 3rd molars
• Rarely deciduous teeth
• sometimes infection, pain, swelling
• infections from partially erupted tooth or extension from a periapical or peridontal lesion that affects an adjacent tooth
• Unilocular radiolucent area that is associated with the crown of an unerupted tooth
• Well-defined and sclerotic border
• Infected cyst may show ill-defined borders
• large ones appear multilocular process because of the persistence of bone
• trabeculae within the radiolucency
• sometimes resorb roots and displace teeth
• radiolucent space surrounding the tooth crown should be at least 3-4mm in diamter
• Radiographic features are not diagnostic for a dentigerous cyst, because other things may have similar features:
• OKC, Unilocular ameloblastoma
• Histopathologic Features:
• Non-inflamed:
• Thin, nonkeratinized epithelial lining (2-4 layers of flattened cells)
• Fibrous CT wall is loosely arranged
• Small islands or cords of inactive-appearing odontogenic epithelial rests may be present in the fibrous wall
• Inflamed:
• Thicker epithelial lining
• Hyperplastic rete ridges
• Fibrous cyst capsule shows diffuse chronic inflammatory infiltrate
• Treatment & Prognosis:
• Enucleation of the cyst and removal of the unerupted tooth
• If eruption of the involved tooth is considered possible, the tooth may be left in place after partial reomval of the cyst wall→ patients may need ortho to assist eruption
• Large cysts may be treated by marsupialization
• Permits decompression of the cyst, with a resulting reduction in the size of the bone defect
• Cyst can be excised at a later date with a less extensive surgical procedure
• Prognosis is usually excellent and recurrence is uncommon after complete removal
• Lining of the cyst can undergo neoplastic transformation to an ameloblastoma
• Squamous cell carcinoma may arise in the lining of the cyst
• Intraosseous mucoepidermoid carcinomas develop from mucous cells in the lining of a dentigerous cyst

• Background: Soft tissue analogue of the dentigerous cyst
• Clinical & Radiographic features: Soft gingival swelling contains considerable blood and can also be designated as an eruption hematoma
• Histopathologic features:
• Cystic epithelial cavity can be seen below the mucosal surface
• Upper epithelial layer is atop a lamina propria with variable inflammatory cell infiltrate
• Roof of the cyst shows a thin layer of nonkeratinizing squamous epithelium
• Treatment & Prognosis: Treatment may not be required because the cyst usually erupts spontaneously, permitting the tooth to erupt

nevoid basal cell carcinoma (Gorlin syndrome)

• Background: Arises from cell rests of the dental lamina
• May be related to inherent factors of the epithelium itself or enzymatic activity in the fibrous wall
• (unlike dentigerous and radicular cysts that enlarge because of osmotic pressure within the lumen)
• Clinical & Radiographic features:
• Small OKCs are usually asymptomatic and discovered only upon x-ray
• Larger OKCs may be associated with pain, swelling or drainage (some may cause no symptoms
• Anteroposterior direction tendency within the medullary cavity of the bone without causing obvious bone expansion
• Multiple OKCs may be present, and such patients should be evaluated for other manifestations of the nevoid basal cell carcinoma (Gorlin) syndrome
• Demonstrate a well-defined radiolucent area with smooth and often corticated margins
• Can radiographically resemble other lesions
• Histopathologic features:
• many have small satellite cysts
• Small satellite cysts, cords or islands of odontogenic epithelium may be seen within the fibrous wall
• Epithelial lining is 6-8 cells thick, with a hyperchromatic and palisaded basal cell layer
• Corrugated parakeratotic surface
• May show heavy chronic inflammatory cell infiltrate
• Treatment & Prognosis:
• Histopathologic confirmation is required for diagnosis
• Treated by enucleation and curettage
• Complete removal of the cyst in one piece is often difficult because of the thin, friable nature of the cyst wall
• OKCs tend to recur after treatment (unlike other odontogenic cysts)
• May be due to fragments of the original cyst that were not removed at time of operation or a new cyst that has developed from dental lamina rests in the general area
• Recurrence occurs more often in mandible
• Long-term clinical and radiographic follow-up is necessary
• Overall prognosis for an OKC is good
• Patients should be evaluated for manifestations of the nevoid basal cell carcinoma syndrome

• Background: Odontogenic cyst that microscopically has an orthokeratinized epithelial lining
• Clinical & Radiographic features:
• Small, unilocular radiolucency
• May be associated with an impacted tooth
• Histopathologic features:
• Thin epithelial lining
• NO palisading
• Keratohyaline granules present
• Thick layer of orthokeratin is seen on the luminal surface
• Treatment & Prognosis:
• Enucleation with curettage is the usual treatment
• Recurrence is rare.

• (GORLIN SYNDROME)
• Background:
• Chief components:
• a) Multiple basal cell carcinomas of the skin
• b) Odontogenic keratocysts
• c) Intracranial calcification
• d) Rib and vertebral anomalies
• Clinical & Radiographic features:
• Major clinical features→ 50% or greater frequency
• 1)Multiple basal cell carcinomas
• Major component of the syndrome
• Syndromic basal cell carcinomas have less aggressive biological behavior than the non-syndromic types
• Usually begin to appear at puberty or in the second to third decades of life, but can also develop in young children
• Odontogenic keratocysts
• Epidermal cysts of the skin
• Palmar/plantar pits→focally depressed area because of thinned keratin layerd Present in 65-80% of patientsi)
• Present in most affected patients
• Calcified falx cerebri
• Enlarged head circumference
• Rib anomalies(splayed, fused, partially missing, bifid)
• Most common skeletal anomaly is a bifid rib or splayed ribs
• May involve several ribs and may be bilateral
• Mild ocular hypertelorism
• Spina bifida occulta of cervical or thoracic vertebrae
• Kyphoscoliosis has been observed in about 30-40% of patients, and a number of other anmalies, such as spina bifida occulta and shortened metacarpals
• Histopathologic features:
• Basal cell tumors of the skin cannot be distinguished from ordinary basal cell carcinomas
• Treatment & Prognosis:
• Most of the anomalies in nevoid basal cell carcinoma syndrome are minor and usually not life threatening
• Prognosis depends on the behavior of the skin tumors
• Radiation therapy should be avoided if at all possible
• Jaw cysts are treated by enucleation, but in may patients, additional cysts will continue to develop
• Genetic counseling is appropriate for affected individuals

• Background:
• Small, superficial, keratin-filled cysts that are found on the alveolar mucosa of infants
• Cysts arise from remnants of the dental lamina
• Common lesions (50% of all newborns)
• Disappear spontaneously by rupture into the oral cavity→ no biopsy needed
• Similar inclusion cysts (Epstein's pearls and Bohn's nodules) are also found in the midline of the palate or laterally on the hard and soft palate
• Clinical & Radiographic features:
• Multiple whitish papules on the mucosa overlying the alveolar ridge of a newborn
• Treatment & Prognosis:
• No treatment is indicated because the lesions spontaneously involute as a result of the rupture of the cysts and resultant contact with the oral mucosal surface
• Lesions are rarely seen after 3 months of age

• Background: Represents the soft tissue counterpart to lateral periodontal cyst
• Clinical & Radiographic features:
• Bluish or blue-gray
• Cyst may cause a superficial "cupping out" of the alveolar bone, which is usually not detected on radiograph but is apparent when the cyst is excised
• Histopathologic features:
• Thin, flattened epithelial lining, with or without focal plaques that contain clear cells (represent rests of the dental lamina)
• May see a plaque-like thickening of the epithelial lining
• Treatment & Prognosis:
• Responds well to surgical excision
• Prognosis is excellent

• Background:
• Uncommon type of developmental odontogenic cyst
• Typically occurs along the lateral root surface of a tooth
• Clinical & Radiographic features:
• 75-80% of cases occur in the mandibular premolar-canine-lateral incisor area
• Well-circumscribed radiolucent area located laterally to the root or roots of vital teeth
• Larger lesions may cause root displacement/divergence
• Clinically may look like a grapelike cluster (multiple cavities)
• Radiographic features are NOT diagnostic
• OKC between roots of teeth may look identical
• Inflammatory radicular cyst that occurs laterally to a root in relation to an accessory foramen or a cyst that arises from a periodontal inflammation also may simulate a lateral periodontal cyst radiographically
• Histopathologic features:
• Thin epithelial lining with focal nodular thickenings, composed chiefly of clear cells
• Thickenings often show a swirling of the cells
• Treatment & Prognosis:
• Can usually be accomplished without damage to the adjacent teeth
• Conservative enucleation= treatment of choice
• Recurrence is unusual

• Background:
• Uncommon
• Innocuous clinical behavior
• Widely recognized historic categorization of the lesion as a cyst
• Clinical & Radiographic features:
• Predominantly intraosseous lesion
• Radiolucent lesion containing calcified structures
• Causes expansion
• Histopathologic features:
• Cyst lining shows ameloblastoma-like epithelial cells, with a columnar basal layer
• Large eosinophilic GHOST CELLS are present within the epithelial lining
• Prognosis for a patient with a calcifying odontogenic cyst is good

• GLANDULAR ODONTOGENIC CYST
• Background: Rare type of developmental odontogenic cyst that can show aggressive behavior

• Background
• uncommon inflammatory odontogenic cyst that develops on the buccal aspect of the mandibular first permanent molar
• Some of these lesions have been associated with teeth that demonstrate buccal enamel extensions into the bifurcation area
• Such extensions may predispose teeth to buccal pocket formation, which could then enlarge to form a cyst in response to periocoronitis
• When the tooth erupts, an inflammatory response may occur in the surrounding follicular tissues that stimulates cyst formation
• Clinical & Radiographic features:
• Typically occurs in children 5-13 years old
• Slight-to-moderate tenderness on the buccal aspect of the mandibular first molar, which may be in the process of erupting
• Associated with swelling and a foul -tasting discharge
• Periodontal probing usually reveals a pocket formation on the buccal aspect of the involved tooth
• 1/3 of patients have bilateral involvement of the first molars
• Radiographs typically show a well-circumscribed unilocular radiolucency involving the buccal bifurcation and root area of the involved tooth
• Lesion may cause lingual displacement of the roots of the first permanent molar
• Histopathologic features:
• Microscopic features are nonspecific and show a cyst that is lined by nonkeratinizing stratified squamous
• epithelium with areas of hyperplasia
• Treatment & Prognosis:
• Enucleation= common tx
• Extraction not necessary
• Within 1 year of surgery, there is usually complete healing with normalization of periodontal probing depths and radiographic evidence of bone fill

• Background:
• Carcinoma arising within bone is a rare lesion that is essentially limited to the jaws
• Because of the putative source of the epithelium giving rise to the carcinoma is odontogenic, these intraosseous jaw carcinomas are collectively known as odontogenic carcinomas
• Some intraosseous mucoepidermoid carcinomas also may arise from mucous cells lining a dentigerous cyst

• schwannoma: benign.
• Left: "Antoni A" with palisading nuclei surrounding pink areas (Verocay bodies).
• Right: "Antoni B" pattern with a looser stroma, fewer cells, and myxoid change.
• S-100+

• Osteoma: tx for esthetics mainly
• periosteal or endosteal
• compact, cancellous
• skull, face, sinuses (frontal)
• mandible>>maxilla
• painless bony hard swellking
• well-definied opacity(density dependent on composition), exophytic or in sinus

Gardner's syndrome: multiple osteomas, dense bone islands(endostosis, supernumery teeth, epidermoid cysts, SubQ dermoid tumors & polyps of intestine.

multiple osteomas, dense bone islands(endostosis, supernumery teeth, epidermoid cysts, SubQ dermoid tumors & polyps of intestine.