Definition of Odontogenic Tumors• Tumor:- The word tumor means swelling.• Odontogenic tumor:- A group of neoplasm & tumors-like malformations arising from cells of odontogenic apparatus & their remnants.- In other words, odontogenic tumors arise from odontogenic tissues.
The Origin of Odontogenic Tumors (Odontogenic Tissues) Ectodermal Mesenchymal(epithelium) (C.T) Dental Lamina + Dental Papilla. (Epith. Rests of Serres) Enamel Organ+ Dental Sac.(Reduced Enamel Epith.) Epith. Root Sheath of Hertwig’s + (Epith. Rests of Malassez)
Classification of Odontogenic Tumors From O.EpithFrom O. From + Epith. O.Mesenchyme Mesenchyme Ameloblastic OdontogenicAmeloblastoma Fibroma Fibroma. (CEOT) Odontogenic Odontoma (Pindborg T) Myxoma. Adenomatoid O.T (AOT)
Origin of AmeloblastomaSeveral origins have been suggested:• Dental Lamina + its remnants( epith. Rests of Serres).• Enamel organ + its remnants ( reduced enamel epith.).• Epith. Lining of Dentigerous cyst.• Basal layer of the oral mucosa.
Types of Ameloblastoma• 1- Simple, Solid,(Multicystic Ameloblastoma), with its histological variants:-Follicular A.-Plexiform A.• 2-(Unicystic Ameloblastoma), with its histological variants:-Luminal Unicystic A.-Intraluminal Unicystic A.-Mural Unicystic A.• 3-Peripheral (S.T) ameloblastoma.• 4-Desmoplastic ameloblastoma.
Solid, Multicystic Ameloblastoma• Def.:- It is a benign but locally invasive neoplasm consisting of epithelium lying in a fibrous stroma.- It is one of the few neoplasms that arise from odontogenic epith.- It has ↑ recurrence rate than other types of Ameloblastoma.
Clinical Features of Multicystic Ameloblastoma• Age: 4th- 5th decade.• Sex: male = female.• Race: ↑ in African.• Site: ↑mand. Molar area.• Signs & symptoms:-painless-Slowly growing.-gradula facial asymmetry.-Looseness of teeth.-NO metastasis (benign).
Macroscopic pictures of Multicystic, Solid Ameloblastoma• Starts in cancellous bone & enlarge slowly.• Extends buccal & lingual plate of bone.• There is always a continous sheet of paper thin bone covering the tumor.• May be solid or cystic.• Cystic tumor may be one large (unicystic) or microcysts (multicystic).
X-ray of Solid, Multicystic Ameloblastoma• Multilocular Radiolucency.• (Honeycomb) or (soap- bubble) appearance.• Recently diagnosed by:- Computed tomography (CT) scan.- Magnetic resonance imaging (MRI).
C.T (3d) MRI forscan for Ameloblastoma Ameloblastoma
Histological Features of Multicystic Ameloblastoma 1-Follicular 2-Plexiform Cystic Acanthomatous Granular Basaloid
Histology of Follicular Ameloblastoma• Epith.: Forms discrete islands. Surrounded by CT stroma.• Epith. Islands:- Central cells →polyhedral or angular cells similar to (stellate reticulum).- Surrounding layer →cuboidal or columnar cells similar to (internal enamel epith.)(preameloblasts).
Histological Variants of Follicular Ameloblastoma• Cystic follicular:- Due to cystic breakdown of the epith. Within the follicle.- The wall of the cyst is formed of (flat cells).
Histological Variants of Follicular Ameloblastoma• Acanthomatous follicular:- Due to squamous metaplasia of inner cells within follicle.- If ↑ keratin →(kerato ameloblastoma).- If some keratinised +- another microcysts with non-keratinised epith.+- papillary forms→ (papilliferous kerato- ameloblastoma).
Histological Variants of Follicular Ameloblastoma• Granular Follicular:- Granular cell metaplasia of inner cells.- Cuboidal rounded large cells.- Nuclei pushed to the cell wall.- Cytoplasm filled with (eosinophilic granules).
Histology of Plexiform Ameloblastoma• Epith.: arranged in network.• Lined by columnar or cuboidal cells + cells similar to (Stelate reticulum).• Cystic formation → by stromal breakdown NOT epith.• Stromal blood vessels dialate → (Haemangio- Ameloblastoma)
Connective Tissue (Stroma) Variants• Acellular loose CT.• OR, hyalaynization around follicle (30µ m).• OR, more collagenous stroma + small nests & strands of epith. →called (Desmoplastic (Desmoplastic Ameloplastoma) Ameloplastoma)
Histological Variants of Unicystic Ameloblastoma• Luminal type:- The change is confined within the luminal surface of the cyst.- Part of the epithelial lining changes into ameloblastic epithelium→ (columnar or cuboidal c)+hyperchromatic nuclei + reverse polarity.- basilar cytoplasmic vacoulation.- The overlying epithelial cells consist of loose stellate reticulum like cells.
Histological Variants of Unicystic Ameloblastoma• Intraluminal type:- The nodules of ameloblastoma proliferate and project into the cyst lining.- The lining often shows an arrangement similar to (plexiform ameloblastoma).
Histological Variants of Unicystic Ameloblastoma• Mural type:- The fibrous connective tissue wall of the cyst is infiltrated by ameloblastic masses.-The ameloblastic component showing (follicular or plexiform patterns).
Adenomatoid Odontogenic Tumor (AOT)• Def.:- A tumor of odontogenic epith.with duct structures & with varing degrees of inductive changes in the C.T stroma.- Its different clinically & histologically from ameloblastoma.- Its believed that the lesion is a (Hamartomatous) in nature.• Origin:-Enamel organ & its remnants(Reduced E.E)
Clinical features of Adenomatoid Odontogenic Tumor (AOT)• Age: 2nd decade.• Sex: F˂M.• Site: Maxilla˂ Mand.-↑↑impacted canine 50%.• Signs & symptoms:- Painless swelling.-Slowly growing(intraosseous)- Associated with impacted tooth.- Similar to (Dentigerous Cyst).
X-ray of (AOT)• Unilocular.• Well-defined.• Radiolucencent.• Associated with impacted tooth.• Especially upper canine.• Similar to (Dentigerous cyst) but its attachment beyond the CEJ.
Histological Features of (AOT)• The epith.:- Whorled masses of spindle cells or,Rings of columnar c.• Rings of columnar c:- Double layer tubular structure.- Duct like structure.- Convoluted bands.- In between double layer +ve to (PAS) stain.• C.T stroma:hayline (epith. Strands, dysplastic dentine& rarly enamel matrix).• Tumor is encapsulated
Calcifying Epith. Odontogenic Tumor (CEOT) (Pindborg’s Tumor)• Def.:- It is a locally invasive epith. Neoplasm characterized by the development of intra- epith. Structure probably of an amyloid-like nature.- This amyloid-like structure may become calcified & liberated into the surrounding stroma.• Origin (Histogenesis):- (Reduced E.E) of associated unerupted tooth.
Clinical Features of (CEOT)(Pindborg’s Tumor)• Age: between 20-60 years.• Sex: M=F• Site:- Intraosseous →mand˂max (post.).- Extraosseous→anterior.• Signs & symptoms:- painless.- Slowly growing.- Associated with impacted tooth.
X-ray of (CEOT)(Pindborg’s Tumor)• Irregular radiolucent area.• Containing radioopaque masses close to unerupted tooth
Ameloblastic Fibroma• Age: ˂ 21 years(young).• Site: mand (post.).• X-ray:- impossible to differentiated from ameloblastoma.- well-defined radiolucent.- Associated with impacted tooth• Diagnosis: by histological examination.
Histology of Ameloblastic Fibroma 1•1→C.T: ↑↑cellular than ameloblastoma ( rounded or angular cells+ ↓↓ collagen)•2→strands or islands of epith.
Histology of Ameloblastic Fibroma 2 1•1→Peripheral epith.Columnar or cuboidal. Cells.•2→narrow cell- free zone (halynization aroundepith.).•3→central stellate reticulum cells with NO cystformation.
Odontoma Compound Odontoma Complex Odontoma• Def.: a malformation in • Def.: a malformation in which all dental tissues which all dental tissues are represented in more are represented in more orderly pattern than disorderly pattern. comlex. • Contains many• Contains many tooth- disordered tooth-like like structures. structures.• Don’t resemble the • Don’t resemble the normal tooth normal tooth morphologically . morphologically .
X-ray of OdontomaCompound ComplexOdontoma Odontoma
Macroscopic Pictures of Odontoma (compound &complex)
Odontogenic Fibroma• Def.:A fibroblastic neoplasm containing:- Inactive odontogenic epith.- More cellular fibrous tissue.- Hard tissue (dysplastic cementum or bone).• Origin:-Tooth follicle (dental sac) →fibroblastic elements or,- Its derivative ( periodontal ligament)
X-ray of Odontogenic Fibroma Well-defined (unilocular) monolocular radioucency
Histology of Odontogenic Fibroma• Primitive cellular fibroblastic tissue.• Strands or islands of inactive odontogenic epith.• Islands of ostoid or cement-like tissue scattered in the fibroblastic mass.• Invariable collagen.• The tumor is encapsulated.
Odontogenic Myxoma• Def.:It is a locally invasive neoplasm resembling dental follicle in location & structure & containing: - Angular spindle cells.- Lying in mucoid stroma.• Origin:- Odontogenic mesenchyme because:1- frequent inclusion of epith. Rests.2- missing associated tooth.3- no similar tumor in any bone type( only jaw).4- similar histologically with embryonic mesenchyme.
Odontogenic Myxoma Clinically• Age: young.• Sex:F=M• Site:-only jaw bone ↑mand.- In place of missing tooth.• Signs & symptoms:- Fusiform swelling.- Rapidly growing.- Difficult complete removal (little encapsulation)- may invade antrum.