adenomatoid odontogenic tumor ( aot ) is a benign , slow - growing , and noninvasive odontogenic lesion associated with an impacted tooth . the presence of so - called unique  duct - like structures  under microscope imparts the tumor a glandular , i.e. , adenomatoid appearance . the tumor is also known as  two third 's tumor  because about 2/3 cases occur in maxilla , about 2/3 cases are diagnosed in young females during the second decade , 2/3 cases are associated with an impacted tooth and in 2/3 cases , impacted tooth is canine . we present a case of unusually large aggressive aot in the maxilla associated with impacted third molar . a 19-year - old male reported with a chief complaint of painless mass over the left side of face and upper left back tooth region since 6 months . initially , pea - sized and asymptomatic swelling appeared in upper left back tooth region . three months later , swelling also appeared below left eye , initially pea - sized . he gave h / o exfoliation of multiple teeth from the same region within these 6 months . on examination , solitary , smooth , roughly spherical - shaped swelling was present on the left side of face below eye . swelling extends from infraorbital region until malar prominence and from medial to lateral corner of left eye measuring approximately 5.0 cm  5.0 cm in maximum dimensions . there was marked obliteration of palpebral fissure of the left eye [ figure 1a ] . intraorally , there was a solitary roughly oval - shaped growth in the left maxillary region , obliterating the buccal vestibule . growth was extending from canine region till retromolar area along alveolar ridge measuring approximately 7 cm  4 cm . overlying mucosa was erythematous , edematous , and inflamed . both extraorally and intraorally , swelling was firm , noncompressible , nonfluctuant , nontender , nonreducible , and nonpulsatile . ( b ) intraoral photograph showing lesion involving palate , alveolar ridge , and buccal vestibule orthopantomogram revealed a huge , diffuse radiolucent lesion extending throughout left maxilla from canine till retromolar region . the lesion was associated with an impacted permanent upper left third molar , which was found to be present below floor of the orbit . computed tomography scan [ figure 3a  c ] demonstrated a large cystic expansile radiolucent lesion with flecks of calcification of varying sizes . the buccal and palatal bony expansion was remarkable , and resorption of bone with perforation was evident . maxillary sinus was completely opaque . on the basis of these radiological findings , aot and pindborg tumor orthopantomogram showing a large radiolucent lesion involving left maxilla , and impacted upper left third molar teeth displaced below floor of orbit by the lesion ( red circle ) ( a - c ) computed tomography scan revealing the expansile radiolucent lesion with few radio - opaque flakes . there is remarkable bony expansion and thinning and discontinuity of the palatal and buccal cortices . having accessed the tumor extraorally as well as intraorally , subtotal maxillectomy was performed , and the involved teeth were also removed [ figure 4b ] . the surgical defect was simultaneously reconstructed using temporalis myofascial flap [ figure 4d ] healing was uneventful . six months after surgery , computed tomogram was done which revealed complete eradication of the lesion [ figure 5a  c ] . there was no evidence of any recurrence 1 year after the surgery [ figure 6a and b ] . ( a - d ) operative photographs ( a - c ) six months postoperative computed tomogram shows normal healing and no signs of recurrence ( a ) one year follow - up photograph . ( b ) one year follow - up intraoral photograph with normal healing histological examination revealed a partially cyst - like cavity lined with the fibrous capsule . rounded and rosette - like aggregates of odontogenic epithelial cells with sparse areas of eosinophilic material could be visualized . the characteristic rounded and rosette form lined with a single layer of polarised cuboidal or columnar epithelium cells giving it the adenomatoid appearance ( h and e , 400 ) aot has three clincopathological variants , namely intraosseous follicular ( 73% ) , intraosseous extrafollicular ( 24% ) , and peripheral ( 3% ) . the intraosseous follicular type is associated with an impacted tooth as in our case , whereas the intraosseous extrafollicular type has no association with an impacted tooth and the peripheral variant is soft tissue component , attached to the gingival structures . the lesion often leads to the expansion of the involved bone and the displacement of the adjacent teeth . owing to the slow growing and painless nature of the tumor , the patients tolerate the swelling for a long duration , sometimes years until it produces an obvious esthetic deformity . it may rarely show aggressive nature such as gaining unusually large size or extending into the intracranial space . radiographically , the lesion often demonstrates as a unilocular radiolucency associated with an impacted tooth . in certain cases , small radiopaque spots ( calcifications ) differential diagnosis of aot includes dentigerous cyst , calcifying odontogenic cyst ( coc ) , calcifying odontogenic tumor ( cot ) ( pindborg tumor ) , and odontogenic keratocyst . radiolucency with multiple radiopaque foci ( particularly when the radiolucency surrounds a portion of the root or entire tooth ) is suggestive of an aot rather than a coc / cot . histologically , aot is mostly surrounded by a well - developed fibrous connective tissue capsule . the tumor is usually composed of spindle - shaped or polygonal cells forming sheets , rosettes or whorled masses in a sparse connective tissue stroma . the amorphous eosinophilic material is present between the epithelial cells as well as in the center of these rosette - like structures . the large size of this lesion has been attributed to a higher growth rate in younger patients and a delay in seeking treatment . however , in our case , the lesion was extremely large in size and expansile . therefore , subtotal maxillectomy with simultaneous reconstruction of surgical defect with temporalis myofascial flap was planned and carried out . the case presented is rare in occurrence because of certain atypical features such as unusual large size , aggressive behavior , the involvement of maxillary third molar , third molar present below floor of orbit , significant bony expansion , and cortical perforation . under general anesthesia , the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed . the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
adenomatoid odontogenic tumor ( aot ) is a rare tumor comprising only 3% of all odontogenic tumors . 
 it is a benign , encapsulated , noninvasive , nonaggressive , slowly growing odontogenic lesion associated with an impacted tooth . 
 these lesions may go unnoticed for years . 
 the usual treatment is enucleation and curettage , and the lesion does not recur . here 
 , we present a rare case of an unusually large aggressive aot of maxilla associated with impacted third molar . the authors also discuss clinical , radiographic , histopathologic , and therapeutic features of the case . 
 subtotal maxillectomy with simultaneous reconstruction of the surgical defect with temporalis myofascial flap was planned and carried out .