Odontogenic Pathology PDF

Odontogenic pathology Cysts Tumors Developmental (dysontogenic) Inflammatory...

Odontogenic pathology Cysts Tumors Developmental (dysontogenic) Inflammatory Benign Malignant 1-Dentigerous cyst 1- Periapical (radicular) cyst Benign Epithelial Benign Mixed Benign mesenchymal 1. Sclerosing odontogenic carcinoma 2-Eruption cyst 2-Residual periapical (radicular) cyst (Epithelial+mesenchymal) 2. Ameloblastic carcinoma 3-Odontogenic keratocyst (OKC) 3-Buccal bifurcation cyst 3. Clear cell odontogenic carcinoma 4-Orthokeratinized odontogenic cyst 4. Ghost cell odontogenic carcinoma 5-Gingival (alveolar) cyst of the newborn 1-Adenomatoid odontogenic tumor 1.odontogenic fibroma 5. Primary intraosseous carcinoma, NOS 6- Gingival cyst of the adult 2-Squamous odontogenic tumor 1- Odontoma 2.Cementoblastoma 6. Odontogenic carcinosarcoma 7-Lateral periodontal cyst 3-Calcifying epithelial odontogenic tumor 2- Primordial odontogenic tumor 3.Cemento-ossifying fibroma 7. Odontogenic sarcoma 8-Calcifying odontogenic cyst 4-Ameloblastoma, unicystic type 3- Ameloblastic fibroma 4.Odontogenic myxoma / 9-Glandular odontogenic cyst 5-Ameloblastoma, extraosseous / peripheral 4- Dentinogenic ghost cell tumor myxofibroma type 6-Metastasizing ameloblastoma 7-Adenoid ameloblastoma  WHO classifications of cysts: Cysts are the following: 1. Inflammatory Cysts (radical cyst). The most common cyst 2. Mandibular Buccal Bifurcation Cyst. 3. Paradental cyst. 4. Dentigerous (follicular) Cyst. 2ed most common after radicular 5. Eruption cyst. 6. Odontogenic keratocyst (OKC). 7. Orthokeratinized odontogenic cyst. 8. Gingival Cyst of the Adult. 9. Lateral Periodontal Cyst. 10. Botryoid Odontogenic Cyst. 11. Calcifying Odontogenic Cyst. 12. Dentinogenic ghost cell tumor. 13. Glandular Odontogenic Cyst. Pathogenesis of cysts in general : -The tooth develops from ingrowth of the lining of the primitive stomodeum called the dental lamina. The dental lamina forms tooth buds for the primary and the permanent dentition And after odontogenesis, remnant epithelium are left behind as rests. - The epithelium of odontogenic cysts is thought to arise from stimulation of such residual odontogenic rests (e.g., rests of Serres in the gingiva or rests of Malassez around the tooth roots in the jawbones). Inflammatory cysts Etiology & Pathogenesis: result of an inflammatory reaction. Inflammatory cysts might present as the following: Periapical (radicular) cyst. Most common Residual periapical (radicular) cyst Buccal bifurcation cyst Periapical Cyst (Radicular Cyst;Apical Periodontal Cyst): Etiology & Pathogenesis: -Epithelium at the apex of a nonvital tooth presumably can be stimulated by inflammation to form a true epithelium lined cyst. - The source of the epithelium is usually a rest of Malassez. - When the cyst and root are removed totally, two variations of periapical cyst have been described: 1-Periapical pocket cysts are characterized by an incomplete epithelial lining because of extension of the apical portion of the tooth into the cyst lumen. 2-Periapical true cysts form a complete epithelium-lined baglike structure that is adjacent to, but separated from, the tooth apex. Clinical Features: - Most periapical cysts grow slowly and do not attain a large size. -No symptoms unless there is an acute inflammatory exacerbation. -if the cyst reaches a large size, then swelling and mild sensitivity may be noted. -Movement and mobility of adjacent teeth are possible as the cyst enlarges. The tooth from which the cyst originated does not respond to thermal and electric pulp testing. -The radiographic pattern is identical to that of a periapical granuloma. -Cysts may develop even in small periapical radiolucencies, and the radiographic size cannot be used for the definitive diagnosis. -Root resorption is common.  -A loss of the lamina dura is seen along the adjacent root, and a rounded radiolucency encircles the affected tooth apex. with enlargement, the radiolucency often flattens out as it approaches adjacent teeth. Significant growth is possible, and lesions occupying an entire quadrant have been noted. -periapical granuloma radiographically resemble periapical cyst. How to differentiate? -Although cysts more frequently achieve greater size than granulomas, neither the size nor the shape of the lesion can be considered a definitive diagnostic criteria. -Periapical cysts also are known to involve deciduous teeth. These are most frequently associated with molar teeth and appear as a radiolucent zone that surrounds the roots and fills the interradicular space at the bifurcation. - A periapical cyst is treated in the same manner as a periapical granuloma: either to extract tooth or RCT. - They are different in their histopathology: periapical granuloma comprises inflamed granulation tissue, while a periapical cyst represents an epithelium-lined cavity with an inflamed fibrovascular connective tissue wall. lateral radicular cyst: -appear along the lateral aspect of the root. -arises from rests of Malassez, and the source of inflammation may be periodontal disease or pulpal necrosis with spread through a lateral foramen. -Radiographically, these cysts mimic developmental lateral periodontal cysts. - Histopathologically, they are consistent with cysts of inflammatory origin. - Lateral radicular cysts appear as discrete radiolucencies along the lateral aspect of the root -Loss of lamina dura and an obvious source of inflammation may not be detected without a high index of suspicion. -Before surgical exploration of laterally positioned radiolucencies, a thorough evaluation of the periodontal status and vitality of adjacent teeth should be performed. Residual Periapical Cyst -The residual periapical cyst appears as a round-to-oval radiolucency of variable size within the alveolar ridge at the site of a previous tooth extraction -As the cyst ages, degeneration of the cellular contents within the lumen occasionally leads to dystrophic calcification and central luminal radiopacity. Histopathological Features: -The histopathologic features of all three types of inflammatory cysts are similar. - The cyst lining consists of nonkeratinized stratified squamous epithelium, which may demonstrate hyperplasia with marked spongiosis and neutrophilic exocytosis. - scattered mucous cells or areas of ciliated pseudostratified columnar epithelium may be noted in periapical cysts (Fig. 3- 29). -The ability of odontogenic epithelium to demonstrate such specialized differentiation represents an example of prosoplasia (forward metaplasia) and highlights the diverse potential of odontogenic epithelium. - The cyst lumen may be filled with fluid and cellular debris. - On occasion, the lining epithelium may demonstrate linear or arch-shaped calcifications known as Rushton bodies (Fig. 3- 30). - The wall of the cyst consists of dense fibrous connective tissue—often with an inflammatory infiltrate containing lymphocytes variably intermixed with neutrophils, plasma cells, histiocytes, and (rarely) mast cells and eosinophils. - Due to the inability of macrophages and giant cells to remove cholesterol, its presence may be partially responsible for failure of healing of cysts in which the original focus of infection was treated appropriately. - Occasionally, the walls of inflammatory cysts will contain scattered hyaline bodies (pulse granuloma, giant-cell hyaline angiopathy). These bodies appear as small, circumscribed pools of eosinophilic material that surrounded by lymphocytes and multinucleated giant cells (Fig. 3-31). these bodies have been shown to represent pools of inflammatory exudate that ultimately undergoes fibrosis and occasionally dystrophic calcification. -The multinucleated giant cells are drawn to the site for rem oval of insoluble hemosiderin granules. -Hyaline bodies may be found in any area of chronic intraosseous inflammation, especially periapical inflammatory disease. Treatment - Non-surgical root canal treatment. - periapical surgery (surgical endo) typically is performed for lesions exceeding 2 cm. - Extraction of tooth. - Biopsy is indicated to rule out other possible pathologic processes if radiolucency fail to resolve. Mandibular Buccal Bifurcation Cyst Etiology & Pathogenesis: The pathogenesis of this cyst is uncertain. -Some of these lesions have been associated with teeth that demonstrate buccal enamel extensions into the bifurcation area -Such extensions may predispose these teeth to buccal pocket formation, which could then enlarge to form a cyst in response to pericoronitis. Clinical Features: -uncommon inflammatory odontogenic cyst -characteristically develops on the buccal aspect of the mandibular first permanent molar. Swelling and pain in the area of the first permanent molar -Children in the first decade (mean age of 7 years) -38% bilateral -Radiolucency around a vital first molar that extends from the furcation (where roots diverge) to the apex of the tooth causing tilting of the roots lingually (best seen on occlusal radiograph) -Periosteal reaction usually present -The paradental cyst is an odontogenic lesion of inflammatory origin (distal or buccal) of mandibular third molar with history of pericoronitis Histological Features: The microscopic features are nonspecific and show a cyst that is lined by nonkeratinizing stratified squamous epithelium with areas of hyperplasia. A prominent chronic inflammatory cell infiltrate is present in the surrounding connective tissue wall. Treatment -Enucleation of the cyst without extraction of the tooth is curative for the buccal bifurcation cyst. -Extraction of the tooth and enucleation of the paradental cyst associated with the third molar is curative Dentigerous (follicular) Cyst Etiology & Pathogenesis: -The dentigerous cyst is defined as a cyst that originates by the separation of the follicle from around the crown of an unerupted tooth attached to the tooth at the cementoenamel junction - The pathogenesis of this cyst is uncertain, but apparently it develops by accumulation of fluid between the reduced enamel epithelium and the tooth crown. -Although most dentigerous cysts are considered to be developmental in origin, there are some examples that appear to have an inflammatory pathogenesis such as: * develop around the crown of an unerupted permanent tooth as a result of periapical inflammation from an overlying primary tooth. * Or partially erupted mandibular third molar Clinical Features: -The most common type of developmental odontogenic cyst. * Usually detected in young adults -Most common sites – mand. 3rd molar region and max. canine region then mand 2nd premolar - causes resorption of adjacent tooth roots. -. Occasionally, they are associated with supernumerary teeth or odontomas. - There is a slight male predilection, and the prevalence is higher for whites than for blacks. - asymptomatic and are discovered only on a routine radiographic examination. - Extensive lesions may result in facial asymmetry. -Dentigerous cysts may become infected and be associated with pain and swelling. - Radiographically: well defined corticated border unilocular radiolucent area associated with the crown of an unerupted tooth. - Radiographic findings are not diagnostic for a dentigerous cyst -The cyst-to-crown relationship shows several radiographic variations.. Histopathological Features: -The histopathologic features of dentigerous cysts vary, depending on whether the cyst is inflamed or not inflamed. -In the noninflamed dentigerous cyst: * cyst us lined with Thin, non-keratinized stratified squamous epithelial lining *The fibrous connective tissue wall is loosely arranged * Scattered mucin-producing cells are present within the epithelial lining. In the inflamed dentigerous cyst, *the fibrous wall is more collagenized, *variable infiltration of chronic inflammatory cells. *The epithelial lining may show varying amounts of hyperplasia with the development of rete ridges and more definite squamous features (Fig. 15-7). *Focal areas of mucous cells may be found in the epithelial lining of dentigerous cysts (Fig. 15-8 *One or several areas of nodular thickening on the luminal surface. These areas must be examined microscopically to rule out the presence of early neoplastic change. *The most important consideration is ensuring that the lesion does not represent a more significant pathologic process (e.g., OKC or ameloblastoma). Treatment: - careful enucleation of the cyst together with removal of the unerupted tooth. - If eruption of the involved tooth is considered feasible, then the tooth may be left in place after partial removal of the cyst wall. - Large dentigerous cysts: mar supialization. - Prognosis is excellent – minimal tendency to recur - Tissue should be submitted for microscopic examination to rule out OKC, central mucoepidermoid carcinoma or ameloblastoma Eruption Cyst Etiology & Pathogenesis: -Essentially represents a dentigerous cyst that forms in the soft tissue overlying the crown of an erupting tooth -The cyst develops as a result of separation of the dental follicle from around the crown of an erupting tooth that is within the soft tissues overlying the alveolar bone. Clinical Features: - soft, often translucent swelling in the gingival mucosa overlying the crown of an erupting deciduous or permanent tooth. -seen in children younger than age 10. -most commonly the first permanent molars, and the deciduous maxillary incisors. -Surface trauma may result in a considerable amount of blood in the cystic fluid, which imparts a blue to purplebrown color (Bluish swelling). eruption hematomas. Histopathological Features: - Intact eruption cysts seldom are submitted to the oral and maxillofacial pathology laboratory, and most examples consist of the excised roof of the cyst, which has been removed to facilitate tooth eruption. - These show surface oral epithelium on the superior aspect. - The underlying lamina propria shows a variable inflammatory cell infiltrate. The deep portion of the specimen, which represents the roof of the cyst, shows a thin layer of nonkeratinizing squamous epithelium. Treatment - Treatment may not be required because the cyst usually ruptures spontaneously, permitting the tooth to erupt. - If this does not occur, then simple excision of the roof of the cyst generally permits speedy eruption of the tooth. Odontogenic keratocyst Etiology & Pathogenesis: -Developmental cyst that arises from cell rests of the dental lamina. -KOC growth related to genetic factors inherent in the epithelium itself or enzymatic activity in the fibrous wall. -OKC regarded as a benign cystic neoplasm rather than a cyst, and in the latest WHO monograph on head and neck tumors, this lesion has been given the name keratocystic odontogenic tumor (KCOT). -These lesions are significant for three reasons: 1. Greater growth potential than most other odontogenic cysts 2. Higher recurrence rate 3. Possible association with the nevoid basal cell carcinoma syndrome Clinical Features -% 3-11of all odontogenic cysts -Affects a wide age range, beginning in the second decade of life( about 60% of all cases are diagnosed in people between 10 and 40 years of age) -There is a slight male predilection. -Asymptomatic until swelling develops, Larger OKCs may be associated with pain, swelling, or drainage. -Most commonly seen in the posterior mandible, but any segment of the jaws can be affected -clinically and radiographically may mimic a wide variety of jaw cysts - well-defined corticated Unilocular radiolucency when small -Multilocular appearance often develops as the lesion enlarges -root Resorption is less than that noted with dentigerous and radicular cysts - OKCs of the anterior midline maxillary region can mimic nasopalatine duct cysts. For unknown reasons, this particular subset of keratocyst usually occurs in older individuals with a mean age of nearly 70 years. -OKCs grow in an anteroposterior direction.This feature may be useful in differential clinical and radiographic diagnosis because dentigerous and radicular cysts of comparable size are usually associated with bony expansion. -Multiple OKCs may be present, and such patients should be evaluated for other manifestations of the nevoid basal cell carcinoma (Gorlin) syndrome. -The diagnosis of OKC is based on the histopathologic features not radiographs.  Histopathological Features: -The OKC typically shows a thin, friable wall, which is often difficult to enucleate from the bone in one piece. -The cystic lumen may contain a clear liquid that is similar to a transudate of serum, or it may be filled with a cheesy material that, consists of keratinaceous debris can be seen when aspiration is done. -The epithelial lining is composed of a uniform layer of stratified squamous epithelium, usually six to eight cells in thickness. -The epithelium and connective tissue interface is usually flat. -Detachment of portions of the cyst-lining epithelium from the fibrous wall is commonly observed. -The luminal surface shows flattened parakeratotic epithelial cells, which exhibit a wavy or corrugated appearance (Fig. 15-17). -The basal epithelial layer is composed of a palisaded layer of cuboidal or columnar epithelial cells, which are often hyperchromatic. -Small satellite cysts, cords, or islands of odontogenic epithelium may be seen within the fibrous wall. Treatment -Depends on extent of lesion -If Small: simple enucleation, complete removal of cyst wall -If Larger: enucleation with/without peripheral ostectomy -Carnoy’s solution after cyst removal (chemical cauterization) -Long term follow-up required (5-10 years) 30% recurrence rate overall -With occurrence in the first decade, or with multiple OKC’s, the nevoid basal cell carcinoma syndrome should be considered Orthokeratinized odontogenic cyst Etiology & Pathogenesis: -Clinically pathologically different than OKC -The designation orthokeratinized odontogenic cyst does not denote a specific clinical type of odontogenic cyst but refers only to an odontogenic cyst that microscopically has an orthokeratinized epithelial lining. -Orthokeratinized odontogenic cysts represent 7% to 17% of all keratinizing jaw cysts. Clinical Features - Orthokeratinized odontogenic cyst. The epithelium produces orthokeratin with an associated granular cell layer. In contrast to odontogenic keratocysts, the basilar cells do not exhibit a palisaded arrangement. -occur predominantly in young adults -2 : 1 male-to-female ratio. Common in mandible than the maxilla with a tendency to involve the posterior areas. -They have no clinical or radiographic features that differentiate them from other inflammatory or developmental odontogenic cysts. -The lesion usually appears as a unilocular radiolucency, but occasional examples have been multilocular. -most often involve an unerupted mandibular third molar tooth. -The size can vary from less than 1 cm to large lesions greater than 7 cm in diameter. Histopathological Features: -The cyst lining is composed of stratified squamous epithelium, which shows an orthokeratotic surface of varying thickness. -Keratohyaline granules may be prominent in the superficial epithelial layer subjacent to the orthokeratin. - The epithelial lining may be relatively thin, and a prominent palisaded basal layer, characteristic of the OKC, is not present (Fig. 15-22). Treatment -Enucleation with curettage -Recurrence is rare 2% - cysts with an orthokeratinized surface may be at slightly greater risk for malignant transformation. -Not associated with nevoid basal cell carcinoma syndrome. Gingival Cyst of the Adult Etiology & Pathogenesis: - an uncommon lesion. -represent the soft tissue counterpart of the lateral periodontal cyst -derived from rests of the dental lamina (rests of Serres). -The diagnosis of gingival cyst of the adult should be restricted to lesions with the same might -arise after gingival graft represent epithelial inclusion cysts that are a result of the surgical procedure. Clinical Features -occur in the mandibular canine and premolar area -most commonly found in middle aged patients in the (5th-6th decades). -They are almost invariably located on the facial gingiva or alveolar mucosa. -Maxillary gingival cysts are usually found in the incisor, canine, and premolar areas. -painless, domelike swellings, usually less than 0.5 cm in diameter. -They are often bluish or blue-gray in color. -In some instances, the cyst may cause a superficial “cupping out” of the alveolar bone, which is usually not detected on a radiograph but is apparent when the cyst is excised. Histopathologi cal Features: Treatment -Conservative excision -Excellent prognosis  Lateral Periodontal Cyst Etiology & Pathogenesis: -an uncommon type of developmental odontogenic cyst. -typically occurs along the lateral root surface of a tooth. - represents the intrabony counterpart of the gingival cyst of the adult. - Derived from dental lamina rests. Clinical Features - asymptomatic -occurs in patients in the fifth through the seventh decades of life. -occur in the mandibular premolar-canine-lateral incisor area. -Maxillary examples also usually involve this same tooth region. -Radiographically, wellcircumscribed radiolucent area located laterally to the root or roots of vital teeth. -less than 1.0 cm in greatest diameter. -lesion may have a polycystic appearance; such examples have been termed botryoid odontogenic cysts. Grossly and microscopically, they show a grapelike cluster of small individual cysts. These lesions are generally considered to represent a variant of the lateral periodontal cyst, possibly the result of cystic degeneration and subsequent fusion of adjacent foci of dental lamina rests. The botryoid variant often shows a multilocular radiographic appearance, but it also may appear unilocular. -OKC that develops between the roots of adjacent teeth may show identical radiographic findings. - An inflammatory radicular cyst that occurs laterally to a root in relation to an accessory foramen or a cyst that arises from periodontal inflammation also may simulate a lateral periodontal cyst radiographically. Histopathological Features: -The lateral periodontal cyst has a thin, noninflamed, fibrous wall. -This epithelium lining consists of flattened squamous cells. -Foci of glycogen-rich clear cells may be interspersed among the lining epithelial cells. -Some cysts show focal nodular thickenings of the liningepithelium, which are composed chiefly of clear cells (Fig. 15-40). -Clear cell epithelial rests sometimes are seen within the fibrous wall. Rarely, lateral periodontal cysts exhibit focal areas that histopathologically are suggestive of the glandular odontogenic cyst. Treatment * Curettage, conservative enucleation * Excellent prognosis Botryoid Odontogenic Cyst Represents variant of lateral periodontal cyst * Similar clinical setting; middle-aged to older adults, mandibular canine and premolar region * Multilocular radiolucency, “grape-like” (botryoid) Treatment : * Conservative surgical excision with curettage * Slight recurrence potential Calcifying Odontogenic Cyst Etiology & Pathogenesis: - Also known as the Gorlin cyst -Most common in 2nd-3rd decades, but wide age range seen -characterized by odontogenic epithelium containing “ghost cells,” which then may undergo calcification. -Although most examples grow in a cystic fashion, some lesions occur as solid tumorlike growths (dentinogenic ghost cell tumor) -The calcifying odontogenic cyst may be associated with other recognized odontogenic tumors, - most commonly odontomas. -adenomatoid odontogenic tumors and ameloblastomas have also been associated with calcifying odontogenic cysts. Clinical Features -Anterior portions of jaw, found in the incisor and canine areas (65%) - occur with equal frequency in the maxilla and mandible. -Usually intrabony, but peripheral lesions make up 13- 30% -The mean age is 30 years, and most cases are diagnosed in the second to fourth decades of life - 1/3rd present with imp acted tooth - 20% present with odontoma - Radiographically: defined unilocular well-defined radiolucency +/- variable radiopacities (irregular calcifications or toothlike densities) - Resorption and divergence of adjacent roots often seen - In approximately one-third of cases, associated with an unerupted canine. -Most calcifying odontogenic cysts are between 2.0 and 4.0 cm in greatest diameter, but lesions as large as 12.0 cm have been noted. Extraosseous examples appearing as localized sessile or pedunculated gingival masses with no distinctive clinical features (Fig. 15-44). -They can resemble common gingival fibromas, gingival cysts, or peripheral giant cell granulomas. -Peripheral examples tend to occur later in life, with peak prevalence during the sixth to eighth decades. Histopathological Features: - well-defined cystic lesion with a fibrous capsule and a lining of odontogenic epithelium. -The basal cells of the epithelial lining may be cuboidal or columnar and are similar to ameloblasts. -The overlying layer of loosely arranged epithelium may resemble the stellate reticulum of an ameloblastoma. -The most characteristic histopathologic feature of the calcifying odontogenic cyst is the presence of variable numbers of “ghost cells” within the epithelial component. These eosinophilic ghost cells are altered epithelial cells that are characterized by the loss of nuclei with preservation of the basic cell outline (Fig. 15-45). -Masses of ghost cells may fuse to form large sheets of amorphous, acellular material. Calcification within the ghost cells is common. Areas of an eosinophilic matrix material represent dysplastic dentin (dentinoid) also may be present adjacent to the epithelial component. Several variants: 1- unifocal or multifocal epithelial proliferation of the cyst lining into the lumen may resemble ameloblastoma : 2- Multiple daughter cysts may be present within the fibrous wall 3- associated with odontomas. This variant is usually a unicystic lesion that shows the features of a calcifying odontogenic cyst together with those of a small complex or compound odontoma. occur intraosseously or extraosseously. The extraosseous: -more common. - show varying-sized islands of odontogenic epithelium in a fibrous stroma. -The epithelial islands show peripheral palisaded columnar cells and central stellate reticulum, which resemble ameloblastoma. -Nests of ghost cells present within the epithelium, and juxtaepithelial dentinoid is commonly present. These features differentiate this lesion from the peripheral ameloblastoma. The intraosseous: -rare. -solid tumor that consists of ameloblastoma-like strands and islands of odontogenic epithelium in a mature fibrous connective tissue stroma. Variable numbers of ghost cells and juxtaepithelial dentinoid are present.  Treatment -Enucleation with curettage for intraosseous lesions, simple excision for peripheral lesions -Recurrences have been documented for both the cystic and the solid variant BUT few. If the lesion is combined with an ameloblastoma, this latter component dictates the most appropriate therapy. Dentinogenic ghost cell tumor. -Dentinogenic ghost cell tumor (DGCT) is a rare tumorous (solid) form of calcifying odontogenic cyst and only a small number of cases have been described. -NO cyst and my be infiltrative or even malignant. -This lesion combines the of an ameloblastoma with intra-epithelial and stromal ghost cells with a dentin-like material. Glandular Odontogenic Cyst. Etiology & Pathogenesis: -The glandular odontogenic cyst is a rare type of developmental odontogenic cyst that can show aggressive behavior. -shows glandular or sal ivary features that presumably are an indication of the pluripotentiality of odontogenic epithelium. Clinical Features -most commonly in middle-aged adults, with a mean age of 46 to 51 years. Common in the mandible. -The cyst has a strong predilection for the anterior region of the jaws, and many mandibular lesions will cross the midline. -vary from small lesions less than 1 cm in diameter to large destructive lesions that may involve most of the jaw. Small cysts may be asymptomatic; however, large cysts often produce clinical expansion, which sometimes can be associated with pain or paresthesia. -Radiographically, the lesion presents as either a unilocular or multilocular radiolucency. -The margins of the radiolucency are usually well defined with a corticated rim. Histopathologist cal Features: Treatment: -Nucleation/Curettage -30% Recurrence -En block resection (multilocular): Because of its potentially aggressive nature and tendency for recurrence, some authors have advocated en bloc resection, particularly for multilocular lesions.  Epithelial odontogenic Tumors are the following: 1. Amelobastoma 2. Ameloblastic carcinoma 3. Adenomatoid odontogenic tumor 4. Calcifying epithelial odontogenic tumor 5. Squamous odntogenic Composed only of odontogenic epithelium without participation of odontogenic ectomesenchyme Benign mixed epithelial+ mesenchymal Odontogenic Tumors are the following: 1. Ameloblastic fibroma 2. Ameloblastic fibroodontoma 3. Odontoma Benign mesenchymal odontogenic tumors are the following : 1. Odontogenic fibroma 2. Odontogenic Myxoma 3. Cementoblastoma Although odontogenic epithelium is present in these lesions, it does not play important role in their pathogenesis Odontogenic tumors in general: Definition: Constitute a group of heterogenous diseases that range from hamartomatous or none neoplastic tissue proliferations to benign neoplsm to malignant tumors with metastatic potential. -They are related to the teeth and teeth producing tissues so dentists should know about them. ‫سمعتها بصوت الدكتورة‬ -Some of the lesions may arise instead of a tooth, be associated with an unerupted tooth, or prevent tooth eruption -They can be misdiagnosed as infection related lesions by some dentists - Some of them can have aggressive growth characteristics and give rise to jaw expansion, and pathological fracture. Glandular Odontogenic Cyst. Etiology & Pathogenesis: - 2nd most common odontogenic tumor. - Tumors of odontogenic epithelial origin. - Arise from rests of dental lamina, from a developing enamel organ, from the epithelial lining of an odontogenic cyst, or from the basal cells of the oral mucosa. -Slow-growing, locally invasive tumors that run a benign course in most cases. They three different clinicoradiographic presentations: 1. Conventional solid or multicystic (about 75% to 86% of all cases) 2. Unicystic (about 13% to 21% of all cases) 3. Peripheral (extraosseous) (about 1% to 4% of all cases) Conventional solid or multicystic intraosseous ameloblastoma Clinical Features: -asymptomatic, -smaller lesions are detected only during a radiographic examination. -painless swelling or expansion of the jaw -rare in children younger than age 10 -equal prevalence in the third to seventh decades of life. -no significant sex predilection. -Some studies indicate a greater frequency in blacks -occur in the mandible, most often in the molar-ascending ramus area. -About 15% to 20% of ameloblastomas occur in the maxilla, usually in the posterior regions. -Pain and paresthesia are uncommon, even with large tumors. -radiographically: multilocular radiolucent lesion, having a “soap bubble” a ppearance (when the radiolucent loculations are large) or being “honeycombed” (when the loculations are small). -Buccal and lingual cortical expansion is frequently present. -Resorption of the roots of teeth adjacent to the tumor is common. -Solid ameloblastomas may radiographically appear as unilocular radiolucent defects, which may resemble any type of cystic lesion. The margins of these radiolucent lesions, however, often show irregular scalloping. -The desmoplastic ameloblastoma occur in the anterior regions of the jaws, with equal distribution between the mandible and the maxilla. Radiographically, these tumors resemble a fibro-osseous lesion because of their mixed radiolucent and radiopaque appearance. This mixed radiographic appearance is due to osseous metaplasia within the dense fibrous septa that characterize the lesion. Histopathological Features: -show a remarkable tendency to undergo cystic change -most tumors have varying combinations of cystic and solid features. -Several microscopic subtypes of conventional ameloblastoma are recognized, but these microscopic -patterns generally have little bearing on the behavior of the tumor. -The follicular and plexiform patterns are the most common. -Less common histopathologic patterns include the acanthomatous, granular cell, desmoplastic, and basal cell types. Follicular Pattern -Islands of epithelium resemble enamel organ epithelium in a mature fibrous connective tissue stroma. -A single layer of tall columnar ameloblastlike cells surrounds this central core. -The nuclei of these cells are located at the opposite pole to the basement membrane (reversed polarity). -cyst formation is common. -If an incisional biopsy is taken from such an area, an inappropriate diagnosis of “unicystic ameloblastoma” may be rendered by the pathologist. Plexiform Pattern -long, anastomosing cords or larger sheets of odontogenic epithelium. -Loosely arranged epithelial cells. -Supporting stroma tends to be loosely arranged and vascular. -Cyst formation is uncommon Acanthomatous Pattern -associated with keratin formation -does not indicate a more aggressive course for the lesion -such a lesion may be confused with squamous cell carcinoma or squamous odontogenic tumor Granular Cell Pattern -transformation of groups of lesional epithelial cells to granular cells. Desmoplastic Pattern -shown increased production of the cytokine known as transforming growth factor-β (TGF-β) Basal Cell Pattern -least common type – contains basaloid cells  Treatment: -Marginal resection (15% recurrence) -Curettage (50%-90% recurrence) Unicystic ameloblastoma Etiology & Pathogenesis: -this lesion might behave in a less aggressive fashion, recent reports have disputed this concept. -Unicystic ameloblastomas account for 10% to 46% of all intraosseous ameloblastomas in various studies. Clinical Features -most often in younger patients. The average 23 years. -in the mandible, usually in the posterior regions. -asymptomatic -large lesions cause a painless swelling of the jaws. -circumscribed radiolucency that surrounds the crown of an unerupted mandibular third molar clinically resembling a dentigerous cyst. -Other tumors appear as sharply defined radiolucent areas and are usually considered to be a primordial, radicular, or residual cyst, depending on the relationship of the lesion to teeth in the area. -In some instances, the radiolucent area may have scalloped margins but is still a unicystic ameloblastoma. Histopathological Features: Different variants: luminal unicystic ameloblastoma -tumor is confined to the luminal surface of the cyst intraluminal unicystic ameloblastoma - nodular proliferation -project from the cystic lining into the lumen of the cyst -also called plexiformunicystic ameloblastomas mural unicystic ameloblastoma fibrous wall of the cyst is infiltrated by typical follicular or plexiform ameloblastoma  Treatment: - These tumors are usually treated as cysts by enucleation and curettage - 10-20% recurrence Peripheral (extraosseous) ameloblastoma. Etiology & Pathogenesis: Uncommon Tumor arises from rests of dental lamina beneath the oral mucosa or from the basal epithelial cells of the surface epithelium. Clinical Features -painless, nonulcerated sessile or pedunculated gingival or alveolar mucosal lesion. -clinical features are non-specific, and most lesions are clinically considered to represent a fibroma or pyogenic granuloma. -commonly found on the posterior gingival and alveolar mucosa -more common in mandible -most are seen in middle-aged persons (52 years) Histopathological Features: Histopathologically, these lesions have the same features as the intraosseous form of the tumor. Treatment: -Respond well to local surgical excession -Though recurrence has been noticed in 10-20 % Metastasizing ameloblastoma. -An ameloblastoma that metastasize in spite of a benign histological appearance -Age: 4-75 years -Metastasis from 1-30 years -Metastases from ameloblastomas are found most often in the lungs. -Cervical lymph nodes are the second most common site for metastasis of an ameloblastoma. Ameloblastic carcinoma An ameloblastoma that has cytological features of malignancy in the primary tumor, in a recurrence, or in any metastatic deposit. Adenomatoid odontogenic tumor Etiology & Pathogenesis: -represents 2% to 7% of all odontogenic tumors -considered to be a variant of the ameloblastoma “adenoameloblastoma,” its clinical features and biologic behavior indicate that it is a separate entity. -sources of the tumor cells have included enamel organ epithelium, reduced enamel epithelium, and rests of Malassez, or from remnants of dental lamina associated with the gubernacular cord. Clinical Features -do not exceed 3 cm in greatest diameter -appear as small, sessile masses on the facial gingiva of the maxilla. -limited to younger patients10 to 19 years of age. -occur in the anterior portions of the jaws -found twice in the maxilla than in the mandible -Females are affected -asymptomatic -Radiographically: 1-follicular type: circumscribed, unilocular radiolucency that involves the crown of an unerupted tooth, most often a canine. Radiographically resemble dentigerous cyst. 2-extrafollicular type -Less often -well delineated unilocular radiolucency that is not related to an unerupted tooth, but rather is located between the roots of erupted teeth -The radiolucency associated with the follicular type of adenomatoid odontogenic tumor sometimes extends apically along the root past the cementoenamel junction. This feature may help to distinguish an adenomatoid odontogenic tumor from a dentigerous cyst. -The lesion may appear completely radiolucent; often, however, it contains fine (snowflake) calcifications. This feature may be helpful in differentiating the adenomatoid odontogenic tumor from a dentigerous cyst.  Histopathological Features: -well-defined lesion surrounded by a thick, fibrous capsule. - central portion of the tumor is solid or may show varying degrees of cystic change -the tumor is composed of spindleshaped epithelial cells that form sheets, strands, or whorled masses of cells in a scant fibrous stroma. -The epithelial cells may form rosettelike structures about a central space, which may be empty or contain small amounts of eosinophilic material. This material may stain for amyloid. -characteristic feature: The tubular or ductlike structure s. These consist of a central space surrounded by a layer of columnar or cuboidal epithelial cells. The nuclei of these cells tend to be polarized away from the central spa ce. not true ducts, and no glandular elements are present -Small foci of calcification may also be scattered throughout the tumor. Treatment: -Because of its capsule , it enucleates easily from the bone -Rare recurrence  Calcifying epithelial odontogenic tumor Etiology & Pathogenesis: The calcifying epithelial odontogenic tumor (Pindborg tumor) -uncommon accounts for less than 1% of all odontogenic tumors. -tumor arises from dental lamina remnants based on its anatomic distribution in the jaws. -Mutations of the PTCH1 gene have been identified in one small series of this neoplasm. -This gene is characteristically associated with nevoid basal cell carcinoma syndrome, but the calcifying epithelial odontogenic tumor is not a component of that condition. Clinical Features -in patients between 30 and 50 years of age. -no sex predilection. found in the mandible, most often in the posterior areas. -painless, slow-growing swelling. -Radiographically: *unilocular or a multilocular radiolucent defect *unilocular pattern encountered more commonly in the maxilla. *The margins scalloped and well defined. -associated with an impacted tooth, most often a mandibular molar. -most prominent around the crown of the impacted tooth. - “driven-snow” pattern of the calcifications is less common. - A few cases of peripheral (extraosseous) calcifying epithelial odontogenic tumor have been reported. These appear as nonspecific, sessile gingival masses, most often on the anterior gingiva. Some of these have been associated with cupped-out erosion of the underlying bone. Histopathological Features: -discrete islands, strands, or sheets of polyhedral epithelial cells in a fibrous stroma -The cellular outlines of the epithelial cells are distinct, and intercellular bridges may be noted. -The nuclei show considerable variation, and giant nuclei may be seen. -Large areas of amorphous, eosinophilic, hyalinized (amyloid-like) extracellular material are also present. -The tumor islands enclose masses of this hyaline material, resulting in a cribriform appearance. -Calcifications, which are a distinctive feature of the tumor, develop within the amyloid-like material and form concentric rings (Liesegang ring calcifications). -The material generally stains as amyloid (i.e., positive staining results with Congo red). After Congo red staining, the amyloid will exhibit apple-green birefringence when viewed with polarized light Treatment: Less aggressive than ameloblastoma 15% recurrence Good prognosis Squamous odontogenic tumor. Etiology & Pathogenesis: -rare benign odontogenic neoplasm -Most of these have been located within bone -represent an atypical acanthomatous ameloblastoma or even a squamous cell carcinoma. -arise from neoplastic transformation of dental lamina rests or perhaps the epithelial rests of Malassez. -originate within the periodontal ligament that is associated with the lateral root surface of an erupted tooth. Clinical Features -A painless or mildly painful gingival swelling, often associated with mobility of the associated teeth. -small lesions that seldom exceed 1.5 cm in greatest diameter. -no apparent sex predilection. -found in patients whose ages ranged from 8 to 74 years (average age, 38). -randomly distributed throughout the alveolar processes of the maxilla and mandible, with no site of predilection. -The radiographic: *not specific or diagnostic *triangular radiolucent defect lateral to the root or roots of the teeth suggests vertical periodontal bone loss. *The radiolucent area is ill defined Histopathological Features: -consist of varying-shaped islands of bland-appearing squamous epithelium in a mature fibrous connective tissue stroma. -The peripheral cell s of the epithelial islands do not show the characteristic polarization seen in ameloblastomas. -individual cell keratinization within the epithelial islands are common features. -Small microcysts are sometimes observed within the epithelial islands. -Islands of epithelium that closely resemble those of the squamous odontogenic tumor have been observed within the fibrous walls of dentigerous and radicular cysts. -These have been designated as squamous odontogenic tumorlike proliferations in odontogenic cysts. -These islands do not appear to have any significance relative to the behavior of the cyst. Treatment: Conservative local excision or curettage Ameloblastic fibroma benign mixed epithelial & mesenchymal odontogenic tumours Etiology & Pathogenesis: -true mixed tumor in which the epithelial and mesenchymal tissues are both neoplastic. Clinical Features -occur in younger patients. encountered in middleaged patients. -more common in males than in females. - asymptomatic; larger tumors are associated with swelling of the jaws. -The posterior mandible is the most common site. - Radiographically: *unilocular or multilocular radiolucent lesion is seen * margins is well defined, and they may be corticated. *An unerupted tooth is associated with the lesion in about 75% of cases Histopathological Features: -solid, soft tissue mass with a smooth outer surface. - tumor is composed of a cell-rich mesenchymal tissue resembling the primitive dental papilla admixed with proliferating odontogenic epithelium. -The most common epithelial pattern consists of long, narrow cords of odontogenic epithelium, often in an anastomosing arrangement. -The mesenchymal portion of the ameloblastic fibroma consists of plump stellate and ovoid cells in a loose matrix, which closely resembles the developing dental papilla.  Treatment: -conservative initial therapy for ameloblastic fibroma. More aggressive surgical excision should probably be reserved for recurrent lesions Ameloblastic fibroodontoma. Etiology & Pathogenesis: -Tumor with features of an ameloblastic fibroma but that also contains enamel and dentin. - stage in the development of an odontoma and do not consider it to be a separate entity Clinical Features -in children with an average age of 10 years. - more frequently in the posterior regions. - Males are more affected. - asymptomatic - largely calcified masses with only a narrow rim of radiolucency about the periphery of the lesion Histopathological Features: -The calcifying element consists of foci of enamel and dentin matrix formation in close relationship to the epithelial structures. - The more calcified lesions show mature dental structures. Treatment: -conservative curettage -excellent, prognosis  Odontoma Etiology & Pathogenesis: -most common types of odontogenic tumors. - Odontomas are considered to be developmental anomalies (hamartomas), rather than true neoplasms. -The compound odontoma is composed of multiple, small toothlike structures. -The complex odontoma consists of a conglomerate mass of enamel and dentin, which bears no anatomic resemblance to a tooth. Clinical Features -first two decades of life, and the mean age 14 years. -Asymptomatic -small and seldom exceed the size of a tooth in the area where they are located. -more frequently in the maxil la than in the mandible. -compound type is more in the anterior maxilla; complex odontomas more in the molar regions. -Radiographically: mass with the radiodensity of tooth structure, which is also surrounded by a narrow radiolucent rim. -may be radiographically confused with an osteoma or some other highly calcified bone lesion. Histopathological Features: -The compound odontoma consists of multiple structures resembling small, single-rooted teeth, contained in a loose fibrous matrix -Complex odontomas consist largely of mature tubular dentin. This dentin encloses clefts or hollow circular structures that contained the mature enamel that was removed during decalcification. Treatment: -simple local excision -prognosis is excellent. Odontogenic fibroma odontogenic ectomesenchyme tumors Etiology & Pathogenesis: Clinical Features -always associated with the crown of an unerupted tooth - ages ranged from 4 to 80 years -strong female predilection -most maxillary lesions located anterior to the first molar Histopathological Features: Treatment: by enucleation and vigorous curettage. Odontogenic Myxoma Etiology & Pathogenesis: Resemble mesenchymal portion of a developing tooth Clinical Features -no sex predilection -common in mandible Histopathological Features: Treatment: by curettage, but careful periodic reevaluation is necessary for at least 5 years. Cementoblastoma (“TRUE CEMENTOMA”) Etiology & Pathogenesis: benign neoplasm of cementoblasts Clinical Features -involve the mandibular first permanent molar -affects young patients -associated tooth usually responds normally to vitality tests. -Radiopaque mass that is fused to one or more tooth roots and is surrounded by a thin radiolucent rim -root resorption and fusion of the tumor with the tooth. Histopathological Features: resemble those of osteoblastoma. However, the primary distinguishing feature of cementoblastoma is fusion with the involved tooth Treatment: -surgical extraction of the tooth and the attached calcified mass. -A potential alternative is excision of the mass with root amputation followed by endodontic treatment of the remaining tooth.