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10 Husam Alhurani Razan al-salaymeh ‫ مايكل الربضي‬: ٠٢٠ ‫تدقيق‬ Name Faleh 1|P ag e Odontogenic tumors 2 -We finished the odontogenic tumors of epithelial origin in the last lecture, now we’re going to talk about odontogenic tumors of mixed origin, starting with: 1)Ameloblastic fibroma: -C...

10 Husam Alhurani Razan al-salaymeh ‫ مايكل الربضي‬: ٠٢٠ ‫تدقيق‬ Name Faleh 1|P ag e Odontogenic tumors 2 -We finished the odontogenic tumors of epithelial origin in the last lecture, now we’re going to talk about odontogenic tumors of mixed origin, starting with: 1)Ameloblastic fibroma: -Compared to the conventional ameloblastoma, it affects younger age groups in the second decade of life (14yrs). -Slowly enlarging painless tumor (similar to conventional ameloblasotoma) -Most common site: mandibular molar region. -Radiographically: the appearance is usually unilocular but sometimes can be multilocular, however, in ameloblastoma it is the opposite, it’s usually multilocular and sometimes unilocular. -Could be associated with unerupted teeth (as in the radiograph above). 2|P ag e -Both components of the tumor are neoplastic. Histologically: -The background of the surrounding tissue is different from ameloblastoma, here it’s composed of dental papillae-like tissue. -Loose, cellular fibromyxoid CT similar to immature developing pulp of teeth (dental papilla). -The epithelium is composed of thin strands and cords of odontogenic epithelium containing less abundant stellate reticulum cells. 3|P ag e -Sometimes we find follicles with cuboidal or columnar cells in the periphery, and center stellate reticulum cells, some of them will have the appearance of Rosette. 2)Primordial odontogenic tumor: -A newly classified mixed odontogenic tumor. -It was first reported in 2014 and included in the odontogenic tumors only in the recent 2017 WHO classification. -Clinically: -Can be seen in children or adolescent in the second decade of life. -Slowly enlarging painless swelling, mostly in the mandibular molar region. -Radiographically: -It can be mixed with dentigerous cysts (dentigerous cysts-like). -Well defined radiolucency, unilocular. -Associated with an unerupted molar. 4|P ag e -Histologically: - ( has some similarities to the histopathology of ameloblastic fibroma) -It is composed of ellipsoidal mass of tissue resembling dental papilla (dental papilla-like myxoid CT similar to ameloblastic fibroma). -Enveloped/covered at the surface with ameloblast-like cells (a delicate membrane of ameloblastic epithelium). 3)Compound and complex odontomes -Quite common, second most prevalent in the list after ameloblastoma. -They are considered hamartomas (not neoplasms). 5|P ag e -They reach fix size ,( they are considered a hamartomas of odontogenic tissue). -Seen in patients in the first& second decades of life (average age=14yrs), associated usually with permanent dentition. Enamel, dentin, cementum and pulp tissues “denticles” -Presentation: 6|P ag e -Can be discovered in radiographs, but sometimes can cause bone expansion so patient present to our clinic (clinical presentation). -In rare cases, the odontomes can erupt as a mass or several small teeth-like structures. -Can be associated with impacted tooth and sometimes odontomes can replace a missing tooth!! So, the patient may come complaining of an impacted/missing tooth and when we take a radiograph, we find that the cause is an odontome. -Radiographically: -Initially: there is no much calcification, so we see the lesion as radiolucent with gradual deposition of radiopaque material that increases in radiopacity with time. -If it is complex odontome, we see it as solid radiopaque mass with a surrounding radiolucent zone , as this two examples in the pic below. 7|P ag e -While if it is compound odontome, we see unilocular radcy containing multiple small teeth-like structures (small denticles), surrounded also by a radiolucent margin like a capsule. -Different examples of compound odontomes 8|P ag e -Histologically: -Compound odontomes: tooth-like arrangement of hard tissue, containing center pulp tissue, so they resemble the teeth but small and malformed, surrounded by fibrous connective tissue stroma. -Complex odontomes: disorganised but well-formed collection of enamel, dentin, cementum and pulp tissues (not organized as the usual arrangement in teeth, just a mixture of all these tissues in the same mass). 9|P ag e 4)Odontogenic Fibroma and Myxoma: -Develop from the odontogenic mesenchyme. -Origin: possibly from periodontal ligament, dental follicle or dental papilla. -Odontogenic fibroma usually clinically cause slowly enlarging painless swelling mainly in the mandible, some cases can present extra-osseous within the gingiva. -Radiographically: non-characteristic well-defined radiolucency. 10 | P a g e -If we take a biopsy (histology ), we will see: -Mature collagen& spindle shaped fibroblasts (mainly, that’s why it’s called fibroma). -Strands of odontogenic epithelium, this what gives the tumor its odontogenic origin (the presence of odontogenic epithelium within the connective tissue gives a hint that the tumor is developing from a mesenchyme of odontogenic origin). -We can see also foci of cementum& dentin-like material /matrix (calcification within the tumor). 5)Odontogenic Myxoma -Clinically: -More common, if we considered the compound& complex odontomes as hamartomas and not tumors, the odontogenic 11 | P a g e myxoma will be the second most common odontogenic tumor following ameloblastoma. -However, the compound and complex odontomes are in the list of WHO classification of odontogenic tumors, so the odontogenic myxoma is considered the third most common tumor in some studies. -It can affect the mandible or maxilla equally. -Painless, slowly enlarging but may be rapidly enlarging sometimes compared to odontogenic fibroma. -It can cause tooth displacement. -Radiographically: compared to odontogenic fibroma, we see odontogenic myxoma as “soap bubble” appearance, well defined multilocular radiolucency that resembles also “tennis racket” appearance. -It resembles/can be mixed with ameloblastoma in radiographs, but histologically there is much difference between them. -Can cause also root resorption 12 | P a g e -Histologically: -Infiltrate of widely separated angular cells with long anastomosing processes in a mucoid ground substance. -We can see islands of odontogenic epithelium within the tumor. -There is no capsule around it, so it’s infiltrative in nature (infiltrates in the maxilla or mandible). -Also, we can see calcifications within the tumor. (Focal calcification) -Sometimes the fibrous connective tissue is prominent, so we call it fibromyxoma in this case. -Prognosis: benign but locally invasive similar to ameloblastoma and the recurrence rate (LRR) can reach up to 25%. -We have to be careful when dealing with benign odontogenic tumors like ameloblastoma, odontogenic myxoma and calcifying epithelial odontogenic tumors because they have a bit high recurrence rate. 13 | P a g e 6)Cementoblastoma -An interesting odontogenic tumor that is easily diagnosed by radiographs. -It is the only true neoplasm/tumor of cementum. -Clinically: -Can be seen in patients in the second or third decade of life, usually less than 25 years of age, mainly affecting males. -Associated in 50% of cases with mandibular first molar, can be seen also in premolar region. -It’s slowly enlarging with 2/3 of cases associated with swelling and pain ,it is an unusual presentation of a tumor to cause pain, remember that cementoblastoma causes pain mainly in first molar region. -If we check vitality of the tooth, we will find that the tooth is vital (the tumor is associated with a vital permanent mandibular first molar). 14 | P a g e -Radiographically: -Initially: well-defined mottled then at the end a radiopaque mass surrounded by a thin radiolucent margin and attached to the roots of the associated tooth usually first molar. -Also, we see resorption of the related roots (the mass is attached to the root causing resorption), this will make the extraction of this tooth very difficult because the mass is attached to the root. -Histologically: -After we remove the tumor surgically, we see that it is surrounded by a capsule. 15 | P a g e -Composed of dense mass of Acellular cementum in a fibrous stroma. -At the periphery of the tumor, there is a zone of an unmineralized tissue containing cementoblasts. 7)Cemento-ossifying fibroma -Used to be discussed in bone tumors, but recently moved to the WHO classification of odontogenic tumors. -Clinically: -Mainly seen in mandibular molar& premolar region. -Causes slowly enlarging painless swelling -Usually affects patients between 20-40 years of age. 16 | P a g e -Radiographically: we see well-defined radiolucency with gradual calcification within the tumor surrounded by radiolucent rim. -Histologically: -Composed of cellular fibrous connective tissue stroma containing trabeculae of bone& numerous cementicles which are round structures of calcified material resembling cementum. -Outer zone of fibrous connective tissue like a capsule, giving a radiolucent rim in radiographs. 8)Juvenile ossifying fibroma: 17 | P a g e -Variant of ossifying fibroma seen in younger patients <15 yrs. -Aggressive variant, rapidly growing. - cellular& mitotically active FCT with trabeculae of woven bone. - LRR. -Malignant odontogenic tumors -Malignant odontogenic tumors are very rare, they could arise from odontogenic epithelium, odontogenic mesenchyme or mixed.  Ameloblastic carcinoma -It is like ameloblastoma but with features of malignancy such as pleomorphism, hyperchromatism, increased mitosis, invasion, metastasis, loss of differentiation. -It can spread to the lymph nodes.  Primary intraosseus carcinoma -It is the same as squamous cell carcinoma that arises from the oral epithelium, but here developing within the bone. 18 | P a g e -Origin: odontogenic epithelium (could be from dental lamina, lining of cystic lesions…) causing proliferation and change into intraosseus carcinoma. -Signs of malignancy!!  Clear cell odontogenic carcinoma -Poorly circumscribed sheets of cells with clear, glycogen-rich cytoplasm. -Could be mixed with metastasis of tumor arising from a renal origin (e.g. renal cell carcinoma).  Odontogenic sarcomas -Fibrosarcomas + we can find non-neoplastic odontogenic epithelium. -Possible presence of dental hard tissue. -e.g. Ameloblastic Fibrosarcoma. -Tumors of debatable origin -Lesions consider with possible odontogenic origin. Congenital epulis (congenital gingival granular cell tumor) 19 | P a g e -Clinically: -Usually present in newborns in the anterior maxilla region. -Present as pedunculated swelling from crest of alveolar ridge that can reach up to several cm. -Mostly in females newborn (10 F: 1M). -Histologically: -Composed of a mass of granular cell tumors (similar histology to granular cell tumor which is a connective tissue tumor that arises mostly in the tongue). 20 | P a g e -However, the surface epithelium is not causing proliferation as seen in granular cell tumor, here the surface epithelium is seen with atrophy. -If we use special stains, we will find that this tumor is negative to S100 protein (it is positive in granular cell tumor). Melanocytic neuroectodermal tumor of infancy -Rare lesion, seen in newborns less than 6 months in age. -Brown or black pigmented swelling in the anterior maxilla usually. -This tumor can arise in other sites extraorally such as brain, skull, testis… -Radiographically: radiolucency mixed with tooth buds displacement (radiolucency associated with developing teeth because as we said it is seen in very young patients). 21 | P a g e Resembling ameloblasts Resembling lymphocytes -Histologically: two types of cells with dense fibrous connective tissue stroma, cells of one type resemble ameloblasts, cells of the other type are similar to lymphocytes (small cells with dark dense nucleus). 22 | P a g e