J Oral Pathol Med 1995: 24: 454-7Primed in Denmark . Alt rights reserved

Copyright © Munksgaard 1995

JOURNAL OF

Oral Palliology&MedicitieISSN 0904-2512

Odontogenic tumors: analysisof 289 Nigerian cases

Onatolu OdukoyaDepartment of Oral Biology & Oral Pathology,College of Medicine, University of Lagos,Lagos, Nigeria

Odtikoya O; Odontogenic tumors: analysis of 289 Nigerian cases. J Oral PatholMed 1995; 24: 454-7. © Munksgaard, 1995.

Two hundred and eighty-nine cases of odontogenic tumors that accumulated inthe files of the biopsy service of the Lagos University Teaching Hospital during aperiod of 21 years were analysed and categorised according to the most recentWHO classification of odontogenic tumors. Odontogenic tumors constituted 19%of all oral/jaw tumors and tumor-like lesions. Ameloblastoma, which accountedfor 58.5% of odontogenic tumors in the series, was the most common, and showeda predilection for males and the posterior mandible. 94.8% of odontogenic tu-mors were benign, while malignant odontogenic tumors accounted for 5.2%). Odon-togenic carcinoma was the most prevalent malignant odontogenic tumor; itshowed a predilection for the mandible and occurred at a mean age of 37 years.

Key words: Nigerians; odontogenic; tumors

Onatolu Odukoya, Dept. of Oral Biology &Oral Pathology, College of Medicine,University of Lagos, PMB 12003, Lagos,Nigeria

Accepted for pubiication iVlay t5, 1995

Odontogenic tumors are uncommonlesions ofthe mandible and maxilla thatconstitute proportions varying from1.11%) (1) to 1.3% (2) of all oral speci-mens. Reports on series of odontogenictumors from different centres have beendocumented (1-4). Odontogenic tumorshave been defined as lesions derivedfrom epithelial or mesenchymal ele-ments, or both, that are part of thetooth-forming apparatus (5). Going bythis definition, only tumors classifiedunder "neoplasms and other tumors re-lated to the odontogenic apparatus" inthe latest WHO histological classifica-tion of odontogenic tumors (6) shouldstrictly be considered as odontogenictumors.

Although a small series of 29 cases ofodontogenic tumors seen over a five-year period has been previously re-ported from Lagos University TeachingHospital (4), it was decided to examinea larger series seen over a longer periodfor a more comprehensive study.Furthermore, the present series hasbeen reviewed in line with the latestWHO classification of odontogenic tu-mors (6).

Material and nnethods

Biopsy records of all histologicallydiagnosed cases of oral tumors and tu-mor-like lesions of the oral cavity andthe jaws during the period from 1971 to

1991 inclusive were retrieved from thefiles ofthe biopsy service ofthe Depart-ment of Oral Biology and Oral Patholo-gy of the Lagos University TeachingHospital. From these cases, 289 exam-ples of odontogenic tumors were se-lected for detailed analysis. Hematoxy-lin and eosin stained sections of theodontogenic tumor cases were retrievedfor review. Information sought on eachcase included age, sex, clinical diagno-sis, site of lesion and histological diag-nosis. The odontogenic tumors selectedwere those classified under "neoplasmsand other tumors related to the odonto-genic apparatus" in the WHO histologi-cal typing of odontogenic tumors (6).

Results

Observation from this series shows thatodontogenic tumors constituted 19% oftumors and tumor-like lesions of theoral cavity and the jaws seen during the

period of study (Table 1). Ameloblasto-ma, which accounted for 58.5%, wasthe most common odontogenic tumor.Distribution of other odontogenic tu-mors is presented in Table 2. Both be-nign and malignant odontogenic tu-mors occur slightly tnore often in males(56%) than in fetnales (44%). The agerange varied from 2'/2-82 years. Theyoungest patient was a case of amelo-blastic fibroma and the oldest in theseries was a case of ameloblastoma(Table 3). Benign odontogenic tumorswere seen more frequently (94.8%) or274 cases) than malignant odontogenictumors (5.2%) or 15 cases). Atneloblas-toma (97.7% or 169 from 173 cases) wasthe most commonly observed odonto-genic tumor categorised as cotiiprising"odontogenic epithelium without odon-togenic mesenchyme" (Table 4). Adeno-matoid odontogenic tumor, which oc-curred more than twice as commonly infemales (72.2%)) as in males (27.8%)),

Table 1. Odontogenie tumors in relation to tumors and tumor-like lesions ofthe oral cavityand the jaws

Tumors No. Percentage

Odontogenic tumorsBenign non-odontogenic tumors and tumor-like lesions of oral cavi-ty/jawsMalignant non-odontogenic tumors and tumor-like lesions of oralcavity/jaws

Total

289

763

459

19.13

50.50

30.38

1511 100

Table 2. Distribution of histological types of odontogenic tumors

Type of tumor Abbreviation No. Percentage

AmeloblastomaSquamous odontogenie tumorCalcifying epithelial odontogenic tumorAmeloblastie fibromaOdontoameloblastomaAdenomatoid odontogenic tumorCalcifying odontogenic cystOdontomaOdontogenie fibromaMyxomaBenign cementoblastomaOdontogenic carcinomaOdontogenic sarcoma

AMELSOT

CEOTAMFOAMAOTCOC

ODTMODFMXMBCBODCODS

16931

132

187

1213342

141

58.471.040.354.500,696,232.424.154.50

11.760.694.840.35

Total

Tiible 3.

Lesion

Age distribution of odontogenic tumors

Age range(years)

Mean age(yr)±SD

289 100,00

Median age(years)

Benign odontogenic tumors(A) Odontogenic epithelium without odontogenic mesenchymeAMEL 10-82 31 ±13.8SOT 35-45 40±5.0CEOT - 21Group (A) 10-82 31.1±13.8

28.040.021.0

29.0

(B) Odontogenic epithelium with odontogenic ectomesenchyme, with or without dental hardtissue formationAMF 2:̂ -45 20.9±13.4 16.0OAM 40-50 45 + 7.1 45.0AOT 10-35 18.4±5.9 17.5COC 14-50 26.4±14.5 26.0ODTM 10-54 20.7+11.7 18.0Group (B) 2^-54 22.3±15.4 18.0

(C) Odontogenic ectomesenchyme with or without included odontogenic epitheliumODF 5-50 25.5±15.1 25.0MXM 8-78 24±16.5 19 5BCB 16-25 20.5 + 6.4 20 5Group (C) 5-78 24.9±15,4 20.0

Malignant odontogenie tumorsODCODS

14-85 36.8±1835

36.035.0

was the most frequently observed odon-togenic tutiior categorised as beingcomposed of "odontogenic epitheliumwith odontogenic mesenchyme with orwithout dental hard tissue formation".Ameloblastie fibroma and odontomawere other relatively common tumors inthis category (Table 4). Myxoma, whichwas the second most common odonto-genic tumor in this series (Table 2), wasthe most commonly observed odonto-genic tumor categorised as exhibiting"odontogenic ectotnesenchyme with orwithout included odontogenic epitheli-um" (Table 4). Benign odontogenic tu-mors categorised as of "odontogenicepithelium without odontogenic ec-tomesenchyme" were more cotnmon inmales (65.3%)) than females (37.7%),

whereas those categorised as of "odon-togenic epithelium with odontogenicmesenchyme, with or without dentalhard tissue formation" occurred morefrequently in females (63.5%)) than inmales (36.5%o). Further observationshowed that malignant odontogenic tu-mors were slightly more common inmales (53.3%) than females (46.7%)),Furthermore, odontogenic carcinoma(93.3%) or 14 from 15 cases) was thetnost common malignant odontogenictumor (Table 4).

Odontogenic tumors, in this series,have a predilection for the tnandible,although adenomatoid odontogenic tu-mor, calcifying odontogenic cyst andodontogenic fibroma showed a predilec-tion for the maxilla (Table 5).

Odontogenie tumors in Nigeriatis 455

Analysis of 169 cases of ameloblasto-ma in this series showed that it occurredat an age range from 10-82 years witha mean age of 31 years (Table 3), wasmore common in males (Table 4) had asite predilection for the posterior man-dible (74%)), with occurrence in the an-terior mandible being 26%) (Table 6).Follicular atneloblastoma (55.1%)) wasthe most common histological type, fol-lowed by the plexiform type (33.3%)).The mixed type (11.6%o), consisting ofthe two tnajor histological types, wasobserved less frequently (Table 7). For-ty-seven cases (28%) of all ameloblasto-mas) qualified as variants of the majorhistological types of ameloblastoma.The acanthomatous variant (78.7%)was the most common of these, fol-lowed by the granular cell variant(14.9%). Clear cell, basal cell and plexi-form unicystic variants were scarce(Table 8).

Discussion

Odontogenic tumors comprised 19.1%)of all tumors and tumor-like lesions ofthe oral cavity and the jaws in the pres-ent series, which is close to a previousreport of 15%) from the same centre (4),thereby suggesting that odontogenic tu-mors are not uticommon lesions in theNigerian environment. Ameloblastomawas the most common odontogenic tu-mor in this exclusively Black popula-tion series; this is consistent with a sim-ilar report in an exclusively Caucasianseries (3), in which ameloblastoma ac-counted for 36.5%) of odontogenic tu-mors and was found to be the mostcommon. Although these findings couldstiggest that ameloblastoma is unlikelyto have a racial predilection for eitherBlacks or Caucasians, a study from aSouth African population has reportedthat ameloblastoma is more common inBlacks than Whites (7). However, it isalso noted that atneloblastotna hasbeen reported in two predominantlyCaucasian series (1, 2) to be the secondmost common odontogenic tumor, andoccurred at a frequency of 10%o (2) or13.52%) (1), while an opinion has beenexpressed that ameloblastoma com-prises 5%o of all odontogenic tumors (8).The male sex predilection observed forameloblastoma in this series differsfrotn previous reports frotn Nigeria (4)and elsewhere (3, 9), in which an equalsex distribution was documented, and afemale predominance reported in an-other series (2). It is important for in-vestigators in the Nigerian environment

456 ODUKOYA

Table 4. Sex distribution of odontogenic tumors

Male Female

Lesion No. No.TotalNo.

Benign odontogenic tumors(A) Odontogenic epithelium without odontogenic mesenchymeAMELSOTCEOT

Subtotal

(B) Odontogenic epitheliumtissue formationAMFOAMAOTCOCODTM

Subtotal

11201

113

66.30

100

65.3

5730

60

with odontogenic ectomesenchyme

61525

19

46.250.027,828.641.7

36.5

71

1357

33

33.7100

0

34.7

16931

173

:, with or without dental hard

46.250.072.271.458.3

63.5

132

187

12

52

(C) Odontogenic ectomesenchyme with or without included odontogenic epitheliumODF 6 46.2 7 53.8 13MXM 12 35.3 22 64.7 34BCB 1 50,0 1 50.0 2

Subtotal 19

Subtotal for benign odontogenic tumors151

Malignant odontogenic tumorsODC 8ODS 0

Subtotal for malignant odontogenic tumors8

Total for benign and malignant odontogenic162

38.8

55.1

57.10

53.3

: tumors56.1

Table 5. Site distribution of odontogenic tumors*

30

123

61

7

127

61.2

44.9

42.9100.0

46.7

43.9

49

274

141

15

289

Site

Lesion

AMELSOTCEOTAMFOAMAOTCOCODTMODFMXMBCBODCODS

No.

14231826145

232

121

Mandible

Percentage

97.910010088.9

10037.5205038.576.7

100100100

No.

30010

104487000

Maxilla

Pereentage

2.100

11.10

62.5805061.523.3

000

Total 210 85 37 15

' Only tumors with known sites (mandible or maxilla) were considered for analysis.

to look into social or other habits ofNigerian males that seem to make themmore susceptible to ameloblastoma.

The predilection of the posteriormandible for ameloblastoma in thisseries differs from a previous report inNigerians (10) in which the anterior

mandible was most affected (74%)among a series of 76 cases of amel-oblastoma; however, it is consistentwith reports from elsewhere (2, 3).

Observation from this series suggeststhat the most likely variant of amel-oblastoma that is encountered in the

Table 6. Site distribution of ameloblastoma*of the mandible

Site

Right posterior mandibleLeft posterior mandibleAnterior mandible

Total

No.

494131

121

Pereentage

40.533.925.6

100

* Only tumors with known speeific side/partof mandible were considered for analysis.

Table 7. Distribution oftypes of ameloblastoma*

Histological type

Follicular ameloblastomaPlexiform ameloblastomaMixed type

Total

major

No,

814917

147

histological

Percentage

49.033.311.6

100.0

* Only tumors for which the record of histo-logieal diagnosis speeified any of the majortypes or which, on review of available H&Esections could be categorised into any of themajor types, were considered for analysis.

Table 8. Distribution of histological variantsof ameloblastoma

Histological variants No. Percentage

Acanthomatous typeGranular cell typeBasal cell typePlexiform uaicystic typeClear cell ameloblastoma

377111

78.714,92.132.132.13

Total 47 99.99

Nigerian environment is the acantho-matous type. Squamous metaplasia,such as that seen in acanthomatousameloblastoma, may be attributed tochronic irritation. Calculus and oralsepsis (which could be a source ofchronic irritation) have been suggestedto play a role in the etiology of amel-oblastoma (10).

Clear cell odontogenic tumor was notobserved in this series, but the only pre-viously diagnosed case of clear cellameloblastoma (11) had biological andclinical behavior that led to it being ini-tially diagnosed as an odontogenic car-cinoma.

Odontogenic myxoma cannot beconsidered rare in this series as it wasobserved to be the second most com-mon odontogenic tumor. While an ex-clusively Caucasian series (3) supportsthe finding that odontogenic myxoma isnot rare, another predominantly Whiteseries reports that the lesion is rare (2).Although an equal sex distribution has

been suggested for odotitogenic myxo-ma (5), the presetit series reports ahigher frequency of occurrence inwomen and is supported by a reportfrorn a Caucasian series (3). Female sexpredilection for adenomatoid odonto-genic tumor, also reported in this series,has been consistently reported byothers (2, 3, 5, 12, 13), and a site predi-lection for the maxilla, as observed inthis series, is also the currently heldopinion (5, 8, 14),

The observed proportions of amelo-blastic fibroma and odontogetiic fi-broma as related to odontogenic tu-mors is similar in this series to thefindings in a Caucasian series (3). Nocase of ameloblastic fibro-odontomawas seen during the period of analysis,Odontoma, which is top of the hst ofodontogenic tutnors in two reports (1,2), was seen much less frequently in thisseries.

Although only seven cases of calcify-ing odotitogenic cyst were observed,their analysis gives an age, sex and sitedistribution that is consistent with whatotherwise obtains in the scientific litera-ture (15),

Squamous odontogenic tutnor, whichwas observed exclusively in females inthis series, has been observed exclu-sively in males in the series reported byGUNHAN et al. (3), However, thesquamous odontogenic tumor, whichwas first described by PULLON et al. in1975 (16), is beheved overall to have nogetider predilection (5),

The observed rarity of cementoblas-toma in this series is supported in thescientific literature (2, 5, 17). Only twocases of cementoblastoma from a seriesof 37 cases of cementoma (personalcotTtmunication) have been docurnentedin this series because cementoblastomais the only type of cementorna listed un-

der "neoplasms and other tumors re-lated to the odontogenic apparatus" inthe recent WHO classification of odon-togenic tumors (6),

Odontogenic carcinoma, which isotherwise cotisidered rare (5), constitues5% of odontogenic tumors in this seriesand cannot be considered rare in theNigerian environmetit. The presentseries includes two previously reportedcases (18, 19). Observation in this seriesthat odontogenic carcinotna constitutesan overwhelming majority of malignantodontogenic tutnors is supported by an-other report of five cases of odontogen-ic carcinoma among a series of six ma-ligtiant odotitogetiic tumors (3).

In conclusion, odontogenic tutnorsare not considered rare in the Nigerianenvifontnent.

Acknowledgements - The author acknowl-edges with thanks the efforts of past andpresent consultant Oral Pathologists whohave contributed to the biopsy service of theDepartment of Oral Biology and Oral Pa-thology of the Lagos University TeachingHospital.

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