8
Cone beam computed tomography signs of desmoplastic ameloblastoma: review of 7 cases Jingjing Luo, BDS, a Meng You, PhD, b Guangning Zheng, PhD, c and Laiqing Xu, BDS a West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China Objective. This study aimed to evaluate and summarize the radiographic features of desmoplastic ameloblastoma (DA) on cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative assessment. Study Design. Seven cases with pathologic diagnosis of DAwere studied retrospectively. A CBCT scan of each individual was analyzed and compared with its corresponding plain (panoramic) radiograph. Results. We found that 71.4% of lesions were located in the anterior or premolar regions (or both) and showed root displacement. With the advent of CBCT imaging, most DA lesions (57.1%) were perceived as having honeycomb appearance totally or dominantly. Distinctively, all the lesions presented cortical expansion with perforation in the buccal/labial side. Conclusions. The typical intralesional structure with honeycomb appearance and the dominant buccal/labial cortical expansion with perforation could be proposed as the characteristic features of DA on CBCT images. CBCT can provide more information for preoperative radiologic assessment of DA compared with panoramic radiography. (Oral Surg Oral Med Oral Pathol Oral Radiol 2014;118:e126-e133) Desmoplastic ameloblastoma (DA) is a rare variant of intraosseous ameloblastoma (IA). It was initially reported in 1984 and termed ameloblastoma with pronounced desmoplasiaby Eversole et al. 1 In 2005, the World Health Organization classication of odon- togenic tumors 2 adopted DA as a histologic type of ameloblastoma with distinct clinical, radiologic, and pathologic features. DA has a predilection for the anterior or premolar region in the mandible or maxilla. 3-5 On plain radiographs, this tumor frequently presented as a mixed radiolucent/radi- opaque lesion with diffused surrounding features, whereas the majority of other IA variants are predominantly radiolucent. Therefore, it was difcult to differentiate DA from bro-osseous lesions in half of the DA cases. 5-7 Histologically, this variant was characterized as extensive stromal collagenization or desmoplasia with small nests and strands of odontogenic epithelium inside. 6-8 Accurate radiologic examination of the lesion and its relationship with surrounding anatomic structures is essential preoperatively. Compared with plain radio- graphic images, cone beam computed tomography (CBCT) scans can provide 3-dimensional (3D) information of the imaged area and more accurately visualize the internal structure and expansion of maxilla-mandible tumors, which can facilitate optimal preoperative planning. 9 However, no previously pub- lished articles have focused specically on the features of DA in CBCT images. By comparing the DA ap- pearances on CBCT and panoramic images, the present study aimed to summarize the features of DA on CBCT images and to provide necessary further information for clinical diagnosis and preoperative assessment. MATERIALS AND METHODS Participant recruitment Patients registered in the West China Stomatology Hospital, Sichuan University, China, with postoperative pathologic diagnosis of DA from May 2011 to April 2013 were recruited in this retrospective study. Post- operative recurrent cases were not eligible to be included in this study. Before any invasive procedure was performed, each patient had gone through panoramic and CBCT imaging in the Department of Oral Radiology. Two radiologists separately evaluated the radiologic features of each a MDS Candidate, State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University. b Assistant Professor, State Key Laboratory of Oral Diseases and Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University. c Professor, Department of Oral Radiology, West China Hospital of Stomatology, Sichuan University. Received for publication Feb 27, 2014; returned for revision Jun 8, 2014; accepted for publication Jul 13, 2014. Ó 2014 Elsevier Inc. 2212-4403 http://dx.doi.org/10.1016/j.oooo.2014.07.008 Statement of Clinical Relevance Cone beam computed tomography can be more helpful (compared with panoramic radiography) in showing the border, internal structure, cortical expansion with erosion, and surrounding structures, which provide radiologists and clinicians more in- formation for preoperative diagnosis of desmoplastic ameloblastoma, such as the honeycomb appearance and labial/buccal expansion with erosion. e126 Vol. 118 No. 4 October 2014 Open access under CC BY-NC-ND license.

Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

  • Upload
    others

  • View
    5

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Vol. 118 No. 4 October 2014

Cone beam computed tomography signs of desmoplasticameloblastoma: review of 7 casesJingjing Luo, BDS,a Meng You, PhD,b Guangning Zheng, PhD,c and Laiqing Xu, BDSa

West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China

Objective. This study aimed to evaluate and summarize the radiographic features of desmoplastic ameloblastoma (DA) on

cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and

preoperative assessment.

Study Design. Seven cases with pathologic diagnosis of DA were studied retrospectively. A CBCT scan of each individual was

analyzed and compared with its corresponding plain (panoramic) radiograph.

Results. We found that 71.4% of lesions were located in the anterior or premolar regions (or both) and showed root

displacement. With the advent of CBCT imaging, most DA lesions (57.1%) were perceived as having honeycomb appearance

totally or dominantly. Distinctively, all the lesions presented cortical expansion with perforation in the buccal/labial side.

Conclusions. The typical intralesional structure with honeycomb appearance and the dominant buccal/labial cortical

expansion with perforation could be proposed as the characteristic features of DA on CBCT images. CBCT can provide more

information for preoperative radiologic assessment of DA compared with panoramic radiography. (Oral Surg Oral Med Oral

Pathol Oral Radiol 2014;118:e126-e133)

Desmoplastic ameloblastoma (DA) is a rare variant ofintraosseous ameloblastoma (IA). It was initiallyreported in 1984 and termed “ameloblastoma withpronounced desmoplasia” by Eversole et al.1 In 2005,the World Health Organization classification of odon-togenic tumors2 adopted DA as a histologic type ofameloblastoma with distinct clinical, radiologic, andpathologic features.

DAhas a predilection for the anterior or premolar regionin the mandible or maxilla.3-5 On plain radiographs, thistumor frequently presented as a mixed radiolucent/radi-opaque lesionwith diffused surrounding features, whereasthe majority of other IA variants are predominantlyradiolucent. Therefore, it was difficult to differentiate DAfrom fibro-osseous lesions in half of the DA cases.5-7

Histologically, this variant was characterized as extensivestromal collagenization or desmoplasia with small nestsand strands of odontogenic epithelium inside.6-8

Accurate radiologic examination of the lesion and itsrelationship with surrounding anatomic structures isessential preoperatively. Compared with plain radio-graphic images, cone beam computed tomography(CBCT) scans can provide 3-dimensional (3D)

aMDS Candidate, State Key Laboratory of Oral Diseases andDepartment of Oral Radiology, West China Hospital of Stomatology,Sichuan University.bAssistant Professor, State Key Laboratory of Oral Diseases andDepartment of Oral Radiology, West China Hospital of Stomatology,Sichuan University.cProfessor, Department of Oral Radiology, West China Hospital ofStomatology, Sichuan University.Received for publication Feb 27, 2014; returned for revision Jun 8,2014; accepted for publication Jul 13, 2014.� 2014 Elsevier Inc.2212-4403http://dx.doi.org/10.1016/j.oooo.2014.07.008

e126

Open access under CC BY-NC-ND license.

information of the imaged area and more accuratelyvisualize the internal structure and expansion ofmaxilla-mandible tumors, which can facilitate optimalpreoperative planning.9 However, no previously pub-lished articles have focused specifically on the featuresof DA in CBCT images. By comparing the DA ap-pearances on CBCT and panoramic images, the presentstudy aimed to summarize the features of DA on CBCTimages and to provide necessary further information forclinical diagnosis and preoperative assessment.

MATERIALS AND METHODSParticipant recruitmentPatients registered in the West China StomatologyHospital, Sichuan University, China, with postoperativepathologic diagnosis of DA from May 2011 to April2013 were recruited in this retrospective study. Post-operative recurrent cases were not eligible to beincluded in this study.

Before any invasive procedure was performed, eachpatient had gone through panoramic and CBCT imagingin the Department of Oral Radiology. Two radiologistsseparately evaluated the radiologic features of each

Statement of Clinical Relevance

Cone beam computed tomography can be morehelpful (compared with panoramic radiography) inshowing the border, internal structure, corticalexpansion with erosion, and surrounding structures,which provide radiologists and clinicians more in-formation for preoperative diagnosis of desmoplasticameloblastoma, such as the honeycomb appearanceand labial/buccal expansion with erosion.

Page 2: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Table I. Clinical features of 7 patients

Case Age (y)/Gender LocationPhysical

examination Treatment

1 40/F MD B and L Resection2 42/M MD B Resection3 39/M MX La and P Resection

OOOO ORIGINAL ARTICLE

Volume 118, Number 4 Luo et al. e127

patient, and the preoperative diagnosis was determined by1 clinician together with the 2 radiologists. The patho-logic diagnosis was achieved by means of postoperativebiopsy and confirmed by 2 pathologists. Clinical datawere obtained from the database of patient records in theDepartment of Maxillofacial Surgery.

4 43/F MD B Resection5 30/F MX B Curettage6 57/M MX La Resection7 43/M MD La and L Resection

MD, mandible; MX, maxilla; B, buccal expansion; L, lingual expan-sion; La, labial expansion; P, palatal expansion.

Table II. Common radiologic features of 7 cases

Case SiteTeeth

displacementRoot

resorptionTooth

impacted

1 Lower left 1st premolar -lower right 1st premolar

(þ) (�) (�)

2 Lower left 2nd premolar -left ramus

(�) (þ) (þ)

3 Upper left central incisor -upper left canine

(þ) (�) (�)

4 Lower right lateral incisor -lower right 1st molar

(þ) (�) (�)

5 Upper left 1st premolar -upper left 2nd molar

(þ) (�) (þ)

6 Upper left central incisor -upper left 1st molar

(�) (�) (�)

7 Lower left 2nd premolar -lower right 1st molar

(þ) (þ) (�)

(þ), positive results; (�), negative results.

Data collectionClinical data including age at time of diagnosis, gender,location (mandible or maxilla), and initial treatmentwere collected. Radiologic data of the DA lesion onboth panoramic and CBCT images were recorded,including site (presented by corresponding tooth posi-tion), locularity (unilocular, multilocular, or honey-comb), radiodensity (radiolucent, mixed, or hybrid),borders (well or ill defined), and effect on involvedteeth (impaction, displacement, or resorption). Someother 3D features, including expansion of the jaw (withthe change of cortex) and effects on surroundingstructures such as maxillary sinus or mandibular canal,were evaluated only on CBCT images.

As for the tooth position, incisors and canines wereregarded as the anterior region. The premolar region isfrom the first premolar to the second premolar. Themolar region is from the first molar to the ramus(mandible) or tuberosity (maxilla). On a panoramicimage, a lesion was considered as unilocular when itpresented as a single mixed radiolucent/radiopaquemass, whereas a lesion was perceived as multilocularwhen it was divided into various compartments bysepta. In comparison, a lesion on a CBCT image wasconsidered as unilocular when a single cystic cavitywas present; as multilocular when septa divided the cystto be soap-bubble shape; or as honeycomb when septadivided the lesion into a honeycomb shape. The hon-eycomb shape included cases that contained a large cysthybridized with the honeycomb portion.

The DA lesions in our study were considered asradiolucent when the shade was presented as a radio-lucent cyst; as mixed when it was radiolucent/radi-opaque; or as hybrid when the lesion contained bothmixed structure and radiolucent cyst. The border wasevaluated as well defined when the lesion was clearlydemarcated or as ill-defined when the lesion had anindistinct boundary. The mandibular canal and maxil-lary sinus were defined as being affected when theiranatomic structures were changed by the lesions.

Panoramic and CBCT projectionThe panoramic radiographs were obtained using theOrthopantomograph OP200 D (InstrumentariumDental). The device was operated at 8 mA, 60 kV witha typical exposure time of 14.1 seconds. All CBCTexaminations were performed using the 3D Accuitomo

(J. Morita Mfg Corp, Kyoto, Japan). The parameterswere set at 4 mA, 85 kV, and a typical exposure time of21 seconds, circling the head in 1 rotation.

RESULTSAmong the 7 cases, the male-to-female ratio was 1.3:1.The age ranged from 30 to 57 years, with a peak(57.1%) in the fourth decade of life and a mean age of42 � 8 years. All 7 cases were intraosseous lesions(42.9% [3 of 7] occurred in the maxilla, and 57.1% [4of 7] occurred in the mandible); 85.7% of patients (6 of7) were treated with resection, whereas only 14.3%(1 of 7) were treated with curettage. Table I shows thedetailed clinical features of all cases.

The common radiologic features in panoramicradiographs and CBCT scans are listed in Table II;71.4% of lesions (5 of 7) were located in the ante-rior or premolar regions (or both), and 28.6% oflesions (2 of 7) occurred in the premolar to molarregion. Root resorption was found in 28.6% of pa-tients (2 of 7), and root displacement was found in71.4% (5 of 7). An impacted tooth was found in28.6% (2 of 7).

On panoramic images, 71.4% of lesions (5 of 7)presented as unilocular and mixed content with

Page 3: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Fig. 1. A, Panoramic view shows a unilocular mixed lesion with an ill-defined border in the right mandible. Root displacement wasseen (arrow). B-D, Cone beam computed tomography 3-dimensional images indicate a honeycomb mixed lesion with a well-defined border in the right mandible. Cortical expansion was mainly buccal. The mandibular canal was pushed down (arrow). E,Histopathologic images exhibit an irregular epithelial island in desmoplastic stroma (original magnification �40), with metaplasticbone embedded with active osteoblasts (black arrow) (original magnification �100).

ORAL AND MAXILLOFACIAL RADIOLOGY OOOO

e128 Luo et al. October 2014

ill-defined border (Figures 1 to 3), whereas the other28.6% (2 of 7) involved multilocular lesions with well-defined borders, including 14.3% (1 of 7) of radiolucentappearance (Figure 4) and another 14.3% (1 of 7) ofhybrid appearance (Figure 5). All the features aredescribed in detail in Table III.

As for the appearances of DA on CBCT images, thedetailed features are listed in Table IV. All the lesionsexhibited well-defined borders on CBCT images;57.1% (4 of 7) were of the honeycomb type, in whichhalf of lesions showed honeycomb-like mixed content(see Figure 1) and the other half were hybrids of hon-eycomb-like structure combined with a cystic portion(see Figure 2). Whereas 28.6% of the lesions (2 of 7)had unilocular appearance with mixed shade (see

Figure 3), 14.3% (1 of 7) displayed radiolucent multi-locular appearance (see Figure 4).

With regard to the radiologic expansion on CBCT,85.7% (6 of 7) exhibited buccolingual or labial-palatalexpansion, which mainly involved the labial/buccalexpansion with thinning of the lingual/palatal cortex,whereas 14.3% (1 of 7) exhibited only buccal expan-sion. All lesions showed cortical erosion in labial/buccal areas. Mandibular canals were displaced in42.9% of cases (3 of 7), and 28.6% of cases (2 of 7)showed deformation of the sinus cavity.

DISCUSSIONDA is a rare variant of ameloblastoma, with an inci-dence of 0.9% to 13% among all ameloblastoma cases

Page 4: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Fig. 2. A, Panoramic view shows a unilocular mixed lesion with an ill-defined border in the anterior region of the mandible. Rootdisplacement was seen without root resorption (arrow). B-D, Cone beam computed tomography 3-dimensional images indicate ahybrid lesion comprising a honeycomb area combined with cystic changes (arrow) and cortical expansion labially. E, Histo-pathologic image exhibits the extensive collagenized stroma containing small tumor epithelial islands with cystic degenerationinside (arrow). Metaplastic bone was seen (original magnification �40).

OOOO ORIGINAL ARTICLE

Volume 118, Number 4 Luo et al. e129

in the literature.3,4,6,7 It is considered as having a pre-dilection for the anterior and premolar regions of thejaw, and tooth displacement frequently happens inthose regions.3-6 One author team summarized that theirpatients with DA had an average age of 42.9 years, amale-to-female ratio of approximately 1:1, and amaxilla-to-mandible ratio of 1:0.9.7 In our study, thedistributions of age, gender, and location were found tobe consistent with those numbers.

Previous studies of DA have summarized features ofmost lesions on plain radiography as mixed radiolucent/radiopaque appearance with ill-defined borders; thus,

they resembled fibro-osseous lesions.5-7 In agreementwith these studies, the appearance on panoramic radi-ography of DA cases in our study showed a similarpattern. Therefore, it appeared that panoramic radiog-raphy cannot provide adequate information to distin-guish DA from fibro-osseous lesions.

Panoramic radiography has inevitable disadvantagesof geometric distortion, superimposition of anatomicstructures, and poor capability for showing finedetails.9,10 The anterior or premolar regions, in whichDA usually occurs, were found to have more overlapwith adjacent structures and higher distortion on

Page 5: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Fig. 3. A, Panoramic view shows a unilocular mixed lesion with an ill-defined border in the left maxilla. B-D, Cone beamcomputed tomography 3-dimensional images indicate a well-defined cystic lesion within flecks of calcification (arrow) and showthat the left canine is impacted. The floor of the left maxillary sinus was pushed up. E, Histopathologic image shows a fewepithelial islands (arrow) scattered in extensive desmoplasia with metaplastic bone (original magnification �40).

ORAL AND MAXILLOFACIAL RADIOLOGY OOOO

e130 Luo et al. October 2014

panoramic images. For instance, DA located in theanterior maxilla region was commonly superimposedwith the nasal basis and maxillary sinus. In this regard,panoramic radiography has intrinsic limitationson its ability to present the fine mixed internal structureof DA.

Compared with panoramic radiography, the 3D viewof CBCT can display the detailed internal structure ofDA. As a newer CT modality, CBCT has a relativelyhigher isotropic spatial resolution of osseous structures

at lower doses of radiation and lower financial cost thanmultidetector CT.9,11

In the previous literature, the lesions with mixedradiolucent/radiopaque content were variouslydescribed as “granular or cloudy,” “needle-like trabec-ular,” “highly dense trabecular,” or having “honeycombappearance.”6,12 In our study, a lesion with honeycombstructure was the dominant type of DA. We furtherclassified the lesions with a honeycomb-like area con-jugated with a radiolucent cystic portion as the hybrid

Page 6: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Fig. 4. A, Panoramic view shows a multilocular radiolucent lesion with a well-defined border and root resorption (arrow) in the leftmandible. B-D, Cone beam computed tomography 3-dimensional images indicate a multilocular radiolucent lesion with soap-bubble appearance (arrow) and buccal expansion with cortical perforation. E, Histopathologic image shows very irregular tumorislands embedded in stroma with massive desmoplasia, without any metaplastic bone (original magnification �40).

OOOO ORIGINAL ARTICLE

Volume 118, Number 4 Luo et al. e131

type, in which the radiolucent cyst varies in its size andsite in individual cases. In some special cases, thehybrid type may be concealed on panoramic radiog-raphy when the radiolucent cyst is located at the labialor lingual side of the lesion and completely overlapswith the honeycomb-like area.

Through the comprehensive analysis of DA images,we suggest that a characteristic CBCT feature of DA isthe honeycomb-like appearance formed by coarsetrabecular septa, which was found in more than half ofour cases. It is obviously distinct from the typicalradiographic features of other types of ameloblastoma,

which are often perceived as unilocular or multilocularradiolucent cystic lesions.6,7,12,13 With clear observa-tion of internal structures in tumors, CBCT can alsobetter distinguish DA from fibro-osseous lesionscompared with panoramic radiography. Besides thehoneycomb-like features, some DA lesions haveplenty of radiopaque flecks scattered around theradiolucent region, which is in agreement with thefindings of other authors.4,5,13 This feature differsfrom the unicystic type of ameloblastoma, which oftenshows a radiolucent cystic lesion without a radiopaquearea.6

Page 7: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Fig. 5. A, Panoramic view shows a hybrid lesion comprising a mixed area combined with large cystic changes (mesial-distal) inthe anterior-premolar region of the mandible. Root displacement (black arrow) and root resorption (white arrow) were seen. B-D,Cone beam computed tomography 3-dimensional images indicate a hybrid lesion with expansion and cortical perforation labially.The large cystic changes were mesial-distal and labial (arrow). E, Histopathologic images exhibit the extensive collagenized stromacontaining tumor epithelial islands with metaplastic bone (original magnification �40). Cystic degenerations were seen in theepithelial islands (arrow) (original magnification �100).

Table III. Panoramic presentation of 7 cases ofdesmoplastic ameloblastoma

Case Locularity Border Radiologic content

1 U I MI2 M W RA3 U I MI4 U I MI5 U I MI6 U I MI7 M W HY

U, unilocular; M, multilocular; I, ill-defined; W, well-defined;MI, mixed; RA, radiolucent; HY, hybrid.

ORAL AND MAXILLOFACIAL RADIOLOGY OOOO

e132 Luo et al. October 2014

Another characteristic CBCT feature of DA that wehave proposed is the apparent expansion of a lesion in thelabial/buccal side with partial cortical erosion, whereasother common IA lesions often exhibit buccolingualexpansion with perforation.14,15 According to Sheikhet al.,4 this feature can adequately confirm that a DAlesion has potentially aggressive behavior. The fact thatmost cases in this studywere treated with partial resectionof the jaw also reflects the concern about this behavior ofDA. Although approximately half of reported DA lesionshad a diffuse radiologic border, which may indicate thatthis tumor is more aggressive than other ameloblastomavariants,6,16 all cases in our study had well-defined bor-ders on CBCT images. It appears that the 3D images can

Page 8: Cone beam computed tomography signs of desmoplastic ...cone beam computed tomography (CBCT) scans and to provide necessary further information for clinical diagnosis and preoperative

Table IV. Cone beam computed tomography presentation of 7 cases of desmoplastic ameloblastoma

Case Locularity Border Radiologic content Jaw expansion Cortical erosionSurrounding structure

involved

1 H W HY B (mainly) and L B None2 M W RA B (mainly) and L B MC3 U W MI La (mainly) and P La None4 H W MI B (mainly) and L B MC5 U W MI B B MS6 H W MI La (mainly) and P La MS7 H W HY La (mainly) and L La MC

U, unilocular; M, multilocular; H, honeycomb-like; W, well-defined; MI, mixed; RA, radiolucent; HY, hybrid; B, buccal; L, lingual; La, labial; P,palatal; MC, mandibular canal; MS, maxillary sinus.

OOOO ORIGINAL ARTICLE

Volume 118, Number 4 Luo et al. e133

avoid the tissue superimposition and provide a more ac-curate and clearer border.

By analyzing the radiographic and histopathologicimages, we found that the metaplastic bone in desmo-plastic stroma was observed only in DA lesions withmixed shade. However, there is no agreement onwhetherthe mixed radiolucent/radiopaque structures came fromnew bone formation or residual bone of tumor destruc-tion.6-8,16 In addition, microcystic degeneration wasobserved in the epithelial islands in the hybrid lesions inour cases. It was speculated that the radiolucent cyst in ahybrid lesion might be developed from these microcystsin the solid mass of DA. This finding corresponded withsome previous studies.7,17

CONCLUSIONCBCT is advantageous in perceiving the borders, in-ternal structure, cortical expansion, and relationshipwith surrounding structures of DA. A typical intrale-sional structure of honeycomb appearance and thedominant labial/buccal expansion with cortical erosionon CBCT images, as well as the common finding ofroot displacement of teeth, may be considered as a trendof features most likely diagnostic of DA.

REFERENCES1. Eversole LR, Leider AS, Hansen LS. Ameloblastomas with pro-

nounced desmoplasia. J Oral Maxillofac Surg. 1984;42:735-740.2. Gardner DG, Heikinheimo K, Shear M, Philipsen HP,

Coleman H. Ameloblastomas. In: Barnes L, Eveson EJ,Reichart P, Sidransky D, eds. World Health Organization Clas-sification of Tumours: Pathology and Genetics of Head and NeckTumors. 3rd ed. Lyon, France: IARC Press; 2005:296-300.

3. Li B, Long X, Wang S, Cheng Y, Chen X. Clinical and radiologicfeatures of desmoplastic ameloblastoma. J Oral Maxillofac Surg.2011;69:2173-2185.

4. Sheikh S, Pallagatti S, Singla I, Kalucha A. Desmoplastic ame-loblastoma: a case report. J Dent Res Dent Clin Dent Prospects.2011;5:27-32.

5. Thompson IOC, Rensburg LJ, Phillips VM. Desmoplastic ame-loblastoma: correlative histopathology, radiology and CT-MRimaging. Oral Pathol Med. 1996;25:405-410.

6. Sun ZJ, Wu YR, Cheng N, Zwahlen A, Zhao YF. Desmoplasticameloblastomada review. Oral Oncol. 2009;45:752-759.

7. Philipsen HP, Reichart PA, Takata T. Desmoplastic amelo-blastoma (including “hybrid” lesion of ameloblastoma): biologicalprofile based on 100 cases from the literature and own files. OralOncol. 2001;37:455-460.

8. Takata T, Miyauchi M, Ito H, et al. Clinical and histopathologicalanalyses of desmoplastic ameloblastoma. Patho Res Pract.1999;195:669-675.

9. Koçak-Berbero�glu H, Çakarer S, Brki�c A, Gurkan-Koseoglu B,Altug-Aydil B, Keskin C. Three-dimensional cone-beamcomputed tomography for diagnosis of keratocystic odontogenictumours: evaluation of four cases. Med Oral Patol Oral CirBucal. 2012;17:e1000-e1005.

10. Munk PL, Morgan-Parkes J, Lee MJ, et al. Introduction topanoramic dental radiography in oncologic practice. AJR AM JRoentgenol. 1997;4:939-943.

11. Liang X, Jacobs R, Hassan B, et al. A comparative evaluation ofcone beam computed tomography (CBCT) and multi-slice CT(MSCT), part I: on subjective image quality. Eur J Radiol.2010;75:265-269.

12. Wakoh M, Harada T, Inoue T. Follicular/desmoplastic hybridameloblastoma with radiographic features of concomitant fibro-osseous and solitary cystic lesions. Oral Surg Oral Med OralPathol Oral Radiol Endod. 2002;94:774-780.

13. Araki M, Matsumoto N, Honda K, et al. Ameloblastoma, des-moplastic type: a case report with characteristic radiologicalpresentation. Oral Radiol. 2012;28:70-73.

14. Ariji Y, Morita M, Katsumata A, et al. Imaging featurescontributing to the diagnosis of ameloblastomas and keratocysticodontogenic tumours: logistic regression analysis. Dentomax-illofac Radiol. 2011;40:133-140.

15. MacDonald-Jankowski D, Yeung R, Lee KM, Li TK. Amelo-blastoma in the Hong Kong Chinese, part 2: systematic review andradiological presentation.DentomaxillofacRadiol. 2004;33:141-151.

16. Philipsen HP, Ormiston IW, Reichart PA. The desmo-andosteoplastic ameloblastoma: histologic variant or clinicopatho-logic entity? Case reports. J Oral Maxillofac Surg. 1992;21:352-357.

17. Santos JN, De Souza VF, Azevêdo RA, Sarmento VA, Souza LB.“Hybrid” lesion of desmoplastic and conventional amelo-blastoma: immunohistochemical aspects. Rev Bras Otorrinolar-ingol. 2006;72:709-713.

Reprint requests:

Meng You, PhDDepartment of Oral RadiologyWest China Hospital of StomatologySichuan UniversityChengdu, Sichuan [email protected]