Unit 12 DDS 6234 DH3234 Benign tumor New growth grows slow Spreads by direct extension Histologically similar to native tissue Hamartoma has limited growth overgrowth of disorganized tissue Hyperplasia has organized growth Slow growing therefore margins are smooth Capsule around the lesion Lucent to mixed content Displaces tooth canal or cortex Resorbs roots perforates cortical bone Hyperostosis in the middle third of the hard palate 20 of the population Depends on race Location On PA or pan attached to and below the hard palate Border Well defined corticated lobulated Internal content Uniformly radiopaque Lingual hyperostosis near the mandibular premolars 8 of the population Unilateral or bilateral Location Superimposed over cervical are of premolars mostly bilateral Border Smooth well defined non corticated margin Internal content Uniformly radiopaque Internal counterpart of exostoses Location Mandible maxilla premolar molar area Periphery Well defined no lucent border no cortication blends Content Uniformly radiopaque Effects on adjacent structure Resorbs or displaces roots Reactive subpontine exostosis Subpontic osseous proliferation hyperplasia Develops from alveolar crest below a pontic Surgical removal if oral hygiene is an issue Odontogenic Tumors Epithelium Epithelium and ectomesenchyme Mixed Ectomesenchyme Locally invasive aggressive yet benign Malignant form of ameloblastoma Multicystic or unicystic Unicystic mural ameloblastoma arising from dentigerous cyst Soft tissue ameloblastoma More often in men in African Average age 40 years Initially asymptomatic Facial swelling early sign Location Molar ramus area In maxilla 3rd molar area Periphery Well defined corticated curved Internal content Totally radiolucent to mixed septa variable size of compartments Effect on adjacent structures Root resorption tooth displacement thinning of the cortical bones perforation May recur after surgery Multiple cyst like appearance May be separated with normal bone Previously termed as odontogenic keratocyst OKC Location Posterior body of the mandible 90 distal to canines Superior to alveolar canal Border Corticated smooth round shape scalloped Internal content Radiolucent keratin does not make radiopaque Effect on adjacent structures Minimal expansion in the body expansion in ramus Displaces or resorbs teeth but less than dentigerous cyst Pindborg tumor Rare less aggressive than ameloblastoma Has mineralized substance Location Similar to ameloblastoma mostly mandibular premolar molar area associated with an impacted tooth Border Usually well defined cyst like cortex Internal structure Unilocular or multilocular Many radiopacities some near the crown of a tooth Thin trabeculation may be present Effects on adjacent structures Displaces tooth prevents eruption Jaw expansion Compound and complex Histologically has mature enamel dentin cementum and pulp Complex No morphological similarity to a tooth Compound Similar to a tooth may be small denticles Location Compound in anterior maxilla complex in mandible Border Well defined soft tissue band corticated margins Internal content Tooth like radiopaque structures Effect on adjacent structures Prevents eruption of normal teeth Large odontomas may expand the jaws Dentigerous cyst Soft odontoma Benign mixed odontogenic tumor Location Premolar molar area of mandible Near alveolar crest occlusal to an impacted tooth Border Well defined corticated Internal content Unilocular radiolucent Multilocular with septa Effects on adjacent structures Expands cortical plate prevents eruption Mixed internal content Larger lesion has extensive calcifications Rare non aggressive tumor May contain dentinoid and enamel matrix Follicular type associated with crown of an impacted tooth Extra follicular type No tooth association Location Mostly maxilla incisor canine premolar region Often associated with an impacted tooth but not limited to the CEJ Border Well defined corticated Internal Content Some radiodense materials in some tumors Others may be lucent Effects on adjacent structures Displacement of teeth Root resorption rare Some expansion but cortex usually intact 17 year old girl with adenomatoid odontogenic tumor Yonetsu K et al Am J Roentgenol 2001 177 937 943 Copyright 2006 by the American Roentgen Ray Society 17 year old girl with adenomatoid odontogenic tumor Yonetsu K et al Am J Roentgenol 2001 177 937 943 Copyright 2007 by the American Roentgen Ray Society Uncommon benign intraosseous lesions Nonencapsulated infiltrates adjacent areas but does not metastasize Only in jaws hence termed odontogenic Location Mandible Maxilla 3 1 In mandible molar premolar area rarely non tooth bearing area In maxilla alveolar process of molar premolar area Border In mandible well defined In maxilla poorly defined Internal content Mixed appearance Straight septa is the clue but many septa are curved Effects on adjacent structures Displaces and loosens teeth Rarely resorbs roots Some expansion True Cementoma Slow growing mesenchymal tumor mostly of cementum Bulbous growth around the apex Mostly with permanent teeth Location Mostly mandible Border Well defined radiopacity surrounded by radiolucent band and then by a corticated margin Internal content Mixed lesion mostly radiodense Root may not be visible Effects on adjacent structures May cause root resorption May expand bone but no perforation Neurilemoma Schwannoma Mandible a common site Pain uncommon Location Mandible Maxilla 10 1 Within expanded inferior alveolar canal or outside mental foramen Border Well defined margin Internal structure Radiolucent Effect on adjacent structures When near the foramen enlarges it Enlarges the canal May resorb roots Nakasato 2000 AJN Moderately firm benign well defined tumors When in mandibular canal causes pain or paresthesia Location In mandibular canal cancellous bone below periosteum Border Sharp corticated fusiform lesion Internal content Unilocular rarely multilocular Effects on adjacent structures Expands or perforates cortex Benign tumor or hamartoma 3 types composed of cortical bone cancellous bone or a combination of both External or internal Location Mandible maxilla usually posterior mandible Paranasal sinuses frontal sinus Border Well defined Internal content Uniformly radiopaque Cancellous type have trabeculation Effects on adjacent structures Displaces structures dysfunction Multiple osteoma multiple enostosis sebaceous cysts multiple polyps of the intestines R F of osteoma