Odontogenic Tumors BDS10009 PDF

BDS10009 Odontogenic Tumors (2) Aims: The aim of this lecture is todetail the principle radiological and histopathological features of non-ameloblastoma odontogenic tumours, odontomes and cemental disorders Objectives: On completion of this lecture, the student should be able to: Understand the spec...

BDS10009 Odontogenic Tumors (2) Aims: The aim of this lecture is todetail the principle radiological and histopathological features of non-ameloblastoma odontogenic tumours, odontomes and cemental disorders Objectives: On completion of this lecture, the student should be able to: Understand the spectrum of odontogenic tumours that may rarely arise Understand the various cemento-ossifying disorders that may occasionally occur Understand the histopathological features and implications of odontomes Odontogenic tumors enamel: epithelial dentine: ectomesenchyme pulp: mesenchyme Epithelial Composed of odontogenic epithelium only Mesenchymal Composed of odontogenic ectomesenchyme only [dental papilla-dental follicle] Benign [ameloblastoma is the most common] Benign Odontogenic carcinomas Odontogenic sarcomas Mixed Composed of both odontogenic epithelium & ectomesenchyme Benign [odontoma is the most common] Odontogenic carcinosarcomas Odontogenic tumors Epithelial Composed of odontogenic epithelium only Benign [ameloblastoma is the most common] Mesenchymal Composed of odontogenic ectomesenchyme only [dental papilla-dental follicle] Benign odontogenic tumor 1. Calcifying epithelial odontogenic tumor 2. Adenomatoid odontogenic tumor Mixed Composed of both odontogenic epithelium & ectomesenchyme Benign [odontoma is the most common] 1.Calcifying epithelial odontogenic tumor (Pindborg tumor) Definition It is a benign epithelial odontogenic tumor that secretes an amyloid protein that tends to calcify Clinical Features Most lesions appear in the posterior area of the mandible. It is a slowly growing tumor ultimately producing bony expansion. 1.Calcifying epithelial odontogenic tumor (Pindborg tumor) Radiographic Features The tumor appears as a circumscribed unilocular multilocular radiolucency. well or It may be associated with an impacted tooth, [50-60% of cases]. The lesion is mostly radiolucent and radiopaque mixed Calcifying epithelial odontogenic tumor (Pindborg tumor) Histopathology Tumor has discrete islands, or sheets of neoplastic epithelial cells. The epithelial cells often have a distinct outline and show prominent intercellular bridges. Nuclei of the neoplastic cells are pleomorphic [this pleomorphism which may raise the possibility of malignancy, but the mitotic rate is low]. 1.Calcifying epithelial odontogenic tumor (Pindborg tumor) Histopathology Neoplastic cells secrete unique odontogenic amyloid protein [eosinophilic hyaline material] Within the eosinophilic material, calcification takes place in the form of concentric rings known as Liesegang ring calcifications. 2. Adenomatoid odontogenic tumor Definition It is a benign epithelial odontogenic tumor that shows duct like structures. These lesions have limited growth potential Clinical features  95% of cases are intraosseous, but extraosseous variant has been documented  anterior part of maxilla  Usually asymptomatic but large lesions may cause painless expansion of bone 2.Adenomatoid odontogenic tumor Radiographic features  Well defined unilocular radiolucency with fine radiopacities  Could be associated with unerupted tooth (Mostly canine) 2.Adenomatoid odontogenic tumor Macroscopy The lesion appears as smooth rounded symmetrical masses.  [this is due to the tumor’s capsule which allows easy removal from bone] Histopathological features  Well defined lesion surrounded by thick fibrous capsule 2.Adenomatoid odontogenic tumor Histopathology  The tumor composed of masses, sheets or strands of spindle cells in scanty fibrous stroma  Duct like structures (central space lined by layer of columnar or cuboidal epithelial cells with polarized nuclei)  Convoluted tubules may also be seen.  Foci of calcification may be scattered throughout the tumor. Odontogenic tumors Mesenchymal Composed of odontogenic ectomesenchyme only [dental papilla-dental follicle] Epithelial Composed of odontogenic epithelium only Benign [ameloblastoma is the most common] 1. 2. 3. 4. Mixed Composed of both odontogenic epithelium & ectomesenchyme Benign Odontogenic myxoma Odontogenic fibroma Cementoblastoma Cemento-osssifying fibroma Benign [odontoma is the most common] 1.Odontogenic myxoma Definition: It is a benign odontogenic neoplasm that mimics microscopically the dental pulp or dental follicle. It is the 3rd frequent after odontoma and ameloblastoma Clinical Features  Wide age range 1-73 Site: The mandible is involved more commonly than the maxilla. Lesions usually show continued growth and cortical perforation may develop 1.Odontogenic myxoma Radiographic Features The myxoma appears as a unilocular or multilocular radiolucency (honeycomb or soap bubble appearance) May displace or cause resorption of teeth in the area of the tumor. Macroscopy Translucent mucinous appearance  Gelatinous in consistency 1.Odontogenic myxoma Histopathology Non-capsulated loosely textured tissue containing large stellate or fusiform cells anastomosing through cytoplasmic processes in faint basophilic mucoid stroma It may contain small islands of inactive odontogenic epithelial rests.  Accumulation of mucoid material is responsible for the rapid growth of the tumor (pseudomalignant growth pattern). 1.Odontogenic myxoma Treatment & prognosis It requires complete excision with safety margin [because myxoma permeates medullary spaces of bone] It has a recurrence rate (about 25%) 2.Odontogenic fibroma Definition: It is a rare neoplasm of mature fibrous tissue Clinical Features  it as 2 clinical variants: intraosseous or central and extraosseous or peripheral Small tumors are asymptomatic Larger tumors may show pain bony expansion and loosening of teeth 2.Odontogenic fibroma Radiographic Features  Small tumors are usually well defined unilocular radiolucency  Large tumors may show multilocular radiolucency  Divergence or resorption of roots of adjacent teeth  An unerupted tooth may be seen 2.Odontogenic fibroma Histopathology It is composed of cellular or collagenous connective tissue Varying amounts of inactive odontogenic epithelium. Foci of calcification may be present. Treatment & prognosis Enucleation and curettage Recurrence is uncommon 3- Cementoblastoma (true cementoma) Rare benign odontogenic neoplasm that is intimately associated with roots of teeth Clinical features  Site: mandibular premolar-molar region  It is associated with the root of a vital tooth.  Pain and swelling are present in approximately 2/3 of reported patients.  Slowly growing 3- Cementoblastoma (true cementoma) Radiographic Features Radiopaque mass fused to root and is surrounded by a thin radiolucent rim Macroscopy Calcified mass adherent to tooth root 3- Cementoblastoma (true cementoma) Histopathology  Calcified cementum like material with reversal lines  The periphery of the lesion is uncalcified [that’s why the lesion appears with a radioloucent rim in radiograph] 3- Cementoblastoma (true cementoma) Treatment & prognosis Surgical extraction of the tooth together with the attached calcified mass. Cemento-ossifying fibroma  it is a distinct type of ossifying fibroma that occurs in tooth bearing areas and is believed to be odontogenic in origin  It will be discussed in details with other fibro-osseous lesions in BDS10005 lecture of bone diseases Odontogenic tumors Epithelial Composed of odontogenic epithelium only Benign [ameloblastoma is the most common] Mesenchymal Composed of odontogenic ectomesenchyme only [dental papilla-dental follicle] Benign Mixed Composed of both odontogenic epithelium & ectomesenchyme Benign [odontoma is the most common] Benign 1. Ameloblastic fibroma Odontogenic 2. Odontomas carcinosarcomas 1. Ameloblastic fibroma It is a true mixed tumor composed of odontogenic epithelium & mesenchyme, in which no dental hard tissues are present Clinical Features Posterior mandible is the most common site Asymptomatic but large tumors are associated with swelling of the jaws 1. Ameloblastic fibroma Radiographic Features  Well defined Unilocular or multilocular (with large lesions) radiolucent lesion  Unerupted tooth is commonly associated with the lesion 1. Ameloblastic fibroma Histopathology The tumor is usually surrounded by fibrous capsule. Mesenchymal portion Epithelial portion  It is myxoid and highly  Long, narrow cords or small cellular [consists of stellate discrete islands of odontogenic cells in a loose matrix epithelium resembling dental papilla] 1. Ameloblastic fibroma Treatment & prognosis  Lesions should be removed conservatively  Extensive destructive tumors should be treated radically 2. Odontoma Odontomas are mixed epithelial and mesenchymal tumor-like malformations (hamartomas) composed of dental hard and soft tissues. Multiple odontomas are seen in association with Gardner’s syndrome] It is characterized by variable abnormalities in bone, skin and teeth as well as colorectal polyps Multiple Fibromas & osteomas Multiple impacted Supernumerary teeth & odontomas Multiple polyps in large intestine (premalignant) The major problem for these patients is high risk for transformation of colorectal polyps into adenocarcinoma if untreated. Multiple osteomas are noted around puberty, leading to early diagnosis 2. Odontoma Odontomas are mixed epithelial and mesenchymal tumor-like malformations (hamartomas) composed of dental hard and soft tissues. It is the most common odontogenic tumors odontomas Compound Composed of multiple small tooth like structures Complex Consists of a mass of enamel & dentin which has no anatomic resemblance to a tooth 2. Odontoma Clinical Features They are frequently associated with unerupted tooth They are asymptomatic often discovered on routine radiographs Compound odontoma Complex odontoma Mainly occur in anterior Mainly occur in posterior maxilla mandible Radiographically, A Radiographically, collection of tooth like disorganized mass of calcified structures tissue 2. Odontoma Macroscopy Compound odontoma A collection of tooth like structures or denticles of varying size and shape Complex odontoma White bony hard mass 2. Odontoma Histopathology Compound odontoma Multiple structures resembling small single rooted teeth (showing dentin, cementum, enamel matrix and pulp) in a loose fibrous matrix Complex odontoma Mature tubular dentin that encloses clefts or hollow circular structures (due to decalcification of mature enamel). A thin layer of cementum is present at the periphery of the mass 3. Odontoma Treatment & prognosis Simple local excision and the prognosis is excellent Aims: The aim of this lecture is todetail the principle radiological and histopathological features of non-ameloblastoma odontogenic tumours, odontomes and cemental disorders Objectives: On completion of this lecture, the student should be able to: Understand the spectrum of odontogenic tumours that may rarely arise Understand the various cemento-ossifying disorders that may occasionally occur Understand the histopathological features and implications of odontomes Reading material: Students are advised to review any relevant teaching provided in the first year. In addition they are advised to read relevant sections of the following texts: Robinson M et al. Soames’ and Southam’s Oral Pathology. 5th edition. Oxford University Press, 2018 pp 149-159 Odell E.W. Cawson’s Essentials of Oral Pathology and Oral Medicine. 9th Edition. Elsevier, 2017 pp 165-179 Reichart PA, Philipsen HP. Odontogenic tumors and allied lesions. Quintessence, 2004 pp 1-387 (reference only) Thank you