Odontogenic Tumors PDF

ODONTOGENIC TUMORS WHAT IS A ODONTOGENIC TUMOURS: are tumors arising from Tooth forming tissues and their remnants (odontogenic tissues) Therefore, they are found exclusively in the mandible and maxilla (and occasionally gingiva). Some of these lesions are true neoplasms. Others may represent...

ODONTOGENIC TUMORS WHAT IS A ODONTOGENIC TUMOURS: are tumors arising from Tooth forming tissues and their remnants (odontogenic tissues) Therefore, they are found exclusively in the mandible and maxilla (and occasionally gingiva). Some of these lesions are true neoplasms. Others may represent tumor-like malformations (hamartomas). The etiology and pathogenesis of this group of lesions are unknown. THE ORIGIN OF ODONTOGENIC TUMORS ECTODERMAL (EPITHELIAL) MESENCHYMAL (CONNECTIVE TISSUE) 1.Dental lamina (Epithelial Rests of Serres). 1. Dental Papilla 2. Enamel Organ (Reduced EnamelEpithelium) 2. Dental Sac (follicle) 3. Epithelial Root Sheath of Hertwig (Epithelial Rests of Malassez). THE ORIGIN OF ODONTOGENIC TUMORS EPITHELIAL ODONTOGENIC MESENCHYMALODONTOGENIC MIXED ODONTOGENIC TUMORS TUMORS TUMORS 1.Ameloblastoma 1.Odontogenic Myxoma. 1.Ameloblastic fibroma. 2.Adenomatoid Odontogenic 2.Odontogenic Fibroma. 2.Odontoma tumor. 3.Cementoblastoma 3.Calcifying Epithelial Odontogenic Tumor. GENERAL FEATURE: Clinically, odontogenic tumors are asymptomatic, although they may cause jaw expansion, movement of teeth, root resorption, and bone loss. Histologically, odontogenic tumors tend to mimic the cell or tissue of origin. So, they may resemble soft tissues of the enamel organ or dental pulp, or they may contain hard tissue elements of enamel, dentin, and/or cementum. ‫ واختصه يف املرسلني كرميا رأفةً باملؤمنني‬،‫ وحباه فضال من لدنه عظيما‬،‫اهلل زاد حممدًا تكرميا‬. ‫رحيما؛ فصلوا عليه وسلموا تسليما‬ By: Dr. Islam Yahya  EPITHELIAL ODONTOGENIC TUMORS 1. AMELOBLASTOMA Definition: It is a benign locally aggressive epithelial odontogenic neoplasm. It is slowly growing. It is the most common odontogenic neoplasm. ORIGIN: (histogenesis) They may arise from: ✓ Dental lamina or its remnants. ✓ Enamel organ or its remnants. ✓ Epithelial lining of an odontogenic cyst. ✓ Basal cells of the oral mucosa. IT OCCURS IN 3 DIFFERENT TYPES WITH DIFFERENT CLINICAL, RADIOGRAPHIC AND HISTOLOGICAL FEATURES : A. Conventional solid or multicystic (intraosseous), (about 86% of Cases) with its histological variants: ✓ Follicular. ✓ Plexiform. B. Unicystic (intraosseous) (about 13% of cases) with its histological variants: ✓ Luminal. ✓ Intraluminal. ✓ Mural. C. Peripheral (extraosseous) (about I % of all cases).  CLINICAL PICTURE AGE : occurs mostly in the fourth and fifth decades of life SITE : About 85% occur in the mandible. most often in the molar-ascending ramus area. About I5% occur in the maxilla, usually in the posterior region. If untreated, the lesion may grow slowly to a massive size. RADIOGRAPHIC FEATURES ✓ It mostly appear as multilocular radiolucent lesion. ✓ “Soap bubble" appearance occurs when the radiolucent loculations are large. ✓ “Honeycomb" appearance occurs when the loculations are small. ✓ It may appear as unilocular radiolucent defects. ✓ In many cases, an unerupted tooth, most often a mandibular third molar, is associated with the radiolucent defect. HISTOPATHOLOGICAL VARIANT OF CONVENTINIAL AMELOBLASTOMA 1.FOLLICULAR 2. PLEXIFORM A. CYSTIC B. ACANTHOMATOUS C. GRANULAR D. BASALOID E. DESMOBLASTIC.  1. FOLLICULAR AMELOBLASTOMA: ✓ Epithelium: Form descrete Islands or nests (resemble enamel organ epithelium) surrounded by connective tissue stroma. ✓ Epithelial nests: ✓ Central cells consist of loosely arranged angular cells resembling the stellate reticulum of an enamel organ. ✓ Surrounding layer consists a single layer of tall columnar ameloblast –like cells. The nuclei of these cells are located at opposite pole to the basement membrane (reversed polarity). CYSTIC FOLLICULAR: ✓ Results from cystic degeneration of the stellate reticulum like cells which will produce microcyst. ✓ The microcyst unite to form larger macrocystic spaces surrounded by flat cells. B. ACANTHOMATOUS AMELOBLASTOMA: ✓ Occurs due to squamous metaplasia of the stellate reticulum like cells of follicular ameloblastoma. ✓ Often associated with keratin formation. C. GRANULAR CELL AMELOBLASTOMA: ✓ Occurs when groups of stellate reticulum like cells show transformation to granular cells. ✓ The granular cells are: ▪ Cuboidal or rounded in shape. ▪ Cytoplasma contains eosenophilic granules. ▪ Nucleus is pushed against the cell membrane. {eccentric nulieus} D. BASALOID AMELOBLASTOMA: ✓ Composed of nests of uniform basaloid cells. ✓ No stellate reticulum is present in the central portions of the nests. ✓ The peripheral cells about the nests tend to be cuboidal rather than columnar. DESMOPLASTIC AMELOBLASTOMA: ✓ contains small islands and cords of odontogenic epithelium in a densely collagenized stroma. 2. PLEXIFORM: ✓ Consists of a network of long, anastomosing cords of odontogenic epithelium lined by columnar or cuboidal ameloblast-like cells and in the center of the cords stellate reticulum like cells are present. ✓ The cords are surrounded by connective tissue stroma. ✓ Cystic formation occurs by stromal breakdown (not epithelial). ✓ In stromal degeneration, stromal blood vessels appear dilated and known as haemangio ameloblastoma. B. Unicystic (intraosseous) (about 13% of cases) with its histological variants: ✓ Luminal. ✓ Intraluminal. ✓ Mural. is a type of ameloblastoma that may originates: ✓ De novo as a neoplasm or, May arise as a result of neoplastic transformation of epithelial lining of dentigerous. Clinically: Most cases are found in the mandible, usually in the posterior regions. Radiographically: Appears as unilocular radiolucency that may contain crown of an unerupted mandibular third molar HISTOPATHOLOGICAL VARIANT OF CONVENTINIAL AMELOBLASTOMA LUMINAL UNICYSTIC AMELOBLASTOMA ✓ The changes occur in the lining of the cyst that consists totally or partially of ameloblastic epithelium. ✓ This demonstrates a basal layer of columnar or cuboidal cells with hyperchromatic nuclei with reverse polarity The overlying epithelial cells consist of stellate reticulum like cells INTRALUMINAL UNICYSTIC AMELOBLASTOMA ✓ One or more nodules of ameloblastoma project from the cystic lining into the ✓ lumen of the cyst similar to plexiform pattern. MURAL UNICYSTIC AMELOBLASTOMA ✓ The fibrous wall of the cyst is infiltrated by follicular or plexiform ameloblastoma PERIPHERAL (EXTRAOSSEOUS) (ABOUT I % OF ALL CASES). Origin: It may arises from rests of dental lamina beneath the oral mucosa or from the basal epithelial cells of the surface epithelium. CLINICAL PICTURE ✓ it is usually a painless, nonulcerated gingival or alveolar mucosal swelling. ✓ most commonly found on the posterior gingival and alveolar mucosa. ✓ more common in mandible than maxilla HISTOPATHOLOGY ✓ these lesions have the same features as the intraosseous form. Connection of the tumor with the basal layer of the surface epithelium is seen in about 50% of cases. RADIOGRAPHICALLY ✓ Negative in x-ray. NB: Rarely, an ameloblastoma exhibits malignant behavior with rapid growth rate and development of metastases. IT is termed Ameloblastic carcinoma. Radiographic features denotes anaggressive lesion with ill-defined margin. Microscopically, the tumor shows The pattern of ameloblastoma in addition to cytologic features of malignancy. These include an increased nuclear- to-cytoplasmic ratio, nuclear hyperchromatism and the presence of mitoses  2. ADENOMATOID ODONTOGENIC TUMOR Definition: It is a benign epithelial odontogenic tumor that contains ductlike structures. Origin: It is derived from enamel organ , or from remnants of dental lamina. CLINICAL PICTURE Age: most cases appearing in the second decade. Site: Most lesions appear in the anterior portion of the maxilla. Size: Most adenomatoid odontogenic tumors are relatively small. RADIOGRAPHIC ✓ the tumor appears as a will circumscribed unilocular radiolucency. ✓ It may involves the crown of an unerupted tooth, most often a canine. ✓ The lesion may contains fine radiopaque calcifications. HISTOPATHOLOGY ✓ 1. The tumor is usually surrounded by a thick, fibrous capsule. ✓ 2. the tumor is composed of spindle shaped epithelial cells that form sheets or strands in a scanty fibrous stroma. ✓ 3. The epithelial cells may form rosette like structures with a central space, which contain small amounts of eosinophilic material. ✓ 4. The tubular or duct like structures are the characteristic feature of this tumor. ✓ 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 space. ✓ 5. Small foci of calcification may also be scattered throughout the tumor.