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2013-02-10 14:10:05
osd5 odontogenic tumors

osd 5 odontogenic tumors
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  1. What is a DENTIGEROUS CYST?
    • 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
  3. What should patients with multiple OKCs be evaluated for?
    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.
    • 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
    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+
  14. What H&N pathology is associated with Gardner's syndrome?
    • 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.
  15. What is Gardner's syndrome?
    multiple osteomas, dense bone islands(endostosis, supernumery teeth, epidermoid cysts, SubQ dermoid tumors & polyps of intestine.