Odontogenic tumours: a 15-year review from Ibadan, Nigeria

( 1997) 35, 363-361

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Odontogenic tumours: a 15-year review from Ibadan, Nigeria J. T. Arotiba, J. 0. Ogunbiyi, A. E. Obiechina Depurtment of Oral and Maxilloj~cial College Hospital, Ihadan, Nigeriu

Surgery; Department oJ’Pathology, Dental Centre, University

SUMMARYI Objective - To establish the incidence of odontogenic tumours in Nigeria we present our experience during the 15year period 1980-94. Design - Retrospective review of histopathological specimens and case notes. Setting - Teaching hospital, Nigeria. Subjects - 128 Patients with histologically confirmed odontogenic tumours out of a total of 415 with tumours of the mouth and jaw. Main outcome measures - Incidence, treatment, and recurrence rate. Results - Ameloblastoma (n = 21,16%) and adenomatoid tumour (n = 16.13%). Patients’ ages ranged from 8 to 75 years (mean 33 for ameloblastoma, 31 for fibromyxoma, and 22 for adenomatoid tumour). The corresponding male:female ratios were 3:2, 2:3, and l:l, and maxilla:mandible ratios 1:9, l.l:l, and 2:l. The more radical the resection of ameloblastomas the less likely were they to recur. Conclusion - Further research is required to explain the high incidence of odontogenic tumours in Nigeria, particularly ameloblastomas.

of tumour, histological type, treatment, and follow-up results were obtained. All the slides were reviewed to confirm the diagnosis, but three were rejected because they did not satisfy the WHO criteria for histological typing of odontogenie tumours.r2

INTRODUCTION Odontogenic tumours are thought to be uncommon among white people’ and there are few data on the relative incidence of this group of oral turnours Early reports in Africans,‘m5 however, indicated that there was a preponderance of such tumours particularly ameloblastoma, in West Africa. Anand et a1.6 concluded that this apparent high incidence could be the result of a ‘harvesting phenomenon’. Studies from Nigeria have documented the epidemiology and clinical features of ameloblastoma, the most common odontogenic tumour seen in this area.7m9 Other odontogenic tumours are seldom reported and there are only a few studies on the relative frequencies of occurrence of odontogenic turnours.“‘,” The University College Hospital, Ibadan, is the first tertiary hospital and a major referral centre in West Africa. This study was carried out to establish the relative incidence of various histological types of odontogenic tumours seen at the Ibadan University College Hospital, Dental Centre over a period of 15 years (1980-94).

RESULTS A total of 423 oral and jaw tumours were seen and diagnosed at the University College Hospital, Ibadan Dental Clinic in the period between January 1980 and December 1994. Only 128 (30%) were confirmed histologically to be odontogenic tumours. With the exception of a few patients who did not return after the tumour had been biopsied, all were seen and managed at our centre. Odontogenic tumours were most common in the second to fourth decades, about 70% of patients being between 11 and 40 years (Table 1). The peak incidence was in the third decade (n = 36). There was an overall male to female ratio of 1.1: 1 (Table 2). Ameloblastoma was the most common histological type (n = 76, 59%) followed by fibromyxoma (n = 2 1, 16%) and adenomatoid tumour (n = 16, 13%). Others including calcifying odontogenic cysts, ameloblastic fibroma and fibrosarcoma, primary intraosseus odontogenic carcinoma, and ameloblastic odontoma were uncommon.

PATIENTS AND METHODS The surgical day book at the department of Oral and Maxillofacial Surgery, the histopathology record books of the department of Oral Pathology and the records from the cancer registry of University College Hospital, Ibadan were reviewed retrospectively to find all oral tumours seen from 1980 to 1994 inclusive. One hundred and thirty-one of the 423 patients with tumours of the mouth and jaw had histologically confirmed odontogenic tumours and their hospital case notes were retrieved and reviewed. Information including age, sex, symptoms and their duration, site

Ameloblastoma There were 76 patients with ameloblastoma with a male (n = 45); female (n = 31) ratio of roughly 3:2. The ages ranged from 8 to 72 years (mean = 33, median = 30) with a peak incidence (30%) in the third decade (Table 1). Sixty-nine patients (91%) had 363

364

British

Table

1 - Age distribution

Histological

Journal

of Oral and MaxiNofacial of patients

type

Figures

are number

with odontogenic Cl0

Ameloblastoma Adenomatoid Fibromyxoma Ameloblastic fibroma Calcifying odontogenic cyst Calcifying epithelial tumour Odontogenic Iibroma Ameloblastic odontoma Ameloblastic fibrosarcoma Intra-alveolar carcinoma Total

Surgery

1 l-20

3 3 1 0 0 0 0 0 0 0 7 (5)

(years)

21-30

16 8 4 1 1 0 1 1 0

23 3 8 1 1 0 0 0 0 0 36 (28)

3: (25)

3140

41-50

51-60

61-70

71-80

14 0 4 0 0 2 0 0 0

9 0 3 1 0 0 0 0 0

6 0 0 1 1 0 0 0 0

4 1 1 0 0 0 1 0 1 0 8

1 1 0 0 0 0 0 0 0

2: (16)

&(3

1: (10)

2 - Histological

type of odontogenic

Ameloblastoma Adenomatoid tumour Fibromyxoma Ameloblastic fibroma Odontogenic fibroma Calcifying epithelial Calcifying odontogenic cyst Primary intraosseus carcinoma Ameloblastic fibrosarcoma Ameloblastic odontoma Total Figures

are number

76 16 21 4 3 2 2 1 1 2 128

tumours

according

to sex

Male

Female

Total

45 (67) 8 (12)

31 8 13 3 2 1 2 1 0 0 61

76 16 21 4

8 (12)

1 (1) 0 1 (1) 1 (1) l(l) 1 (1) 1 (1) 67

(51) (13) (21) (5) (3)

(59) (13) (16) (3)

(2)

2 (2) 2 (2)

(3)

3 (2)

(2)

2 (2) l(l) 10) 128

(%) of patients

3 - Sites of 125 odontogenic

tumours

No. of Patients

Anterior

Maxilla

Ameloblastoma Adenomatoid Fibromyxoma Ameloblastic fibroma Odontogenic tibroma Primary intra-alveolar carcinoma Calcifying odontogenic cyst Calcifying epithelial tumour Ameloblastic sarcoma Ameloblastic odontoma

(6)

Total

(%) of patients Table

Table

turnouts

Posterior

Mandible Anterio/ posterior

Not specified

Anterior

Posterior

Anteriol posterior

Posterior/ ramus

Not specified

76 16 21

15 2 3

19 1 4

8 0 1

17 0 1

10 2 1

4

0

2

0

1

0

2

0

0

0

0

0

0

2

2

0

0

1

1

0

1

0

3

0

0

0

1

1

1

0

0

0

2

0

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

0

1

mandibular lesions and seven (9%) had maxillary lesions (Table 3). The most common site involved was the posterior mandible (horizontal ramus n = 44, 80%). The exact site was not recorded in 10 mandibular and two maxillary lesions. The median duration of symptoms was 21 months (range 1 month ~ 15 years.) Four (5%) out of the 76 were recurrent lesions that had been treated primarily elsewhere. Two of the recurrent lesions were judged clinically to be malignant with evidence of metastatic lesions in the lungs.

Radiological features showed 68 (90%) multilocular and eight unilocular lesions. Wide excision with an adequate margin of normal bone was done for 42 patients; 26 underwent mandibulectomy, 7 segmental resection; 9 en-bloc resection with preservation of the lower cortical plate; 4 complete and 2 partial, maxillectomies. Twenty patients with unilocular or small multilocular mandibular lesions had enucleation and curettage with saucerization of the resulting wound.

Odontogenic

Reconstruction, with bone graft (n = 2) adapted Steinmann’s pins (n = 16) or Kirshner wires (n = 4) was carried out in 22 mandibular lesions while maxillary obturators were constructed for post-maxillectomy rehabilitation. The tumours varied in size with the largest in the series weighing about 300 g with 13 teeth within it. On histological examination, benign squamous metaplasia was seen in some cases that had previously been called acanthotic. Our follow-up period ranged from 2 weeks to 10 years (median = 12 months). Of 68 patients whose treatment records were adequate, 13 developed recurrences. The rate of recurrence differed between mandibular lesions treated by wide resection (10%) and those treated by conservative excision (40%). Adenomatoid tumour

Of the 16 patients (13%) with adenomatoid tumours, half were male and half female, with an age range from 9 to 75 years (mean = 22, median = 15). The peak incidence was in the second decade (50%). The tumour affected the maxilla in 11 patients (69%) and the mandible in five patients (31%). Eight tumours were in the anterior maxilla and duration of the symptoms varied from 3 months to 12 years (median = 12 months). Treatment was usually surgical enucleation under general anaesthesia. The lesions varied in size from 1 to 3.5 cm and most had well-defined fibrous capsules. Follow-up ranged from 2 weeks to 24 months and there were no recurrences. Fibromyxoma

There were 21 patients (16%) with odontogenic fibromyxomas; 8 were male and 13 female (M:F ratio 2:3), with an age range of lo-65 years (mean = 31, median = 30). The peak incidence (38%) was in the third decade of life. The mandible (n = 10) and the maxilla (n = 11) were almost equally affected. Treatment was either by radical resection or conservative excision with trimming of the bony edge as appropriate for the size of the lesion. Follow-up, which was available for only 16 patients, ranged from 3 months to 12 years. Three patients who had been treated primarily by conservative excision and one patient by mandibulectomy developed recurrences. Ameloblastic fibroma

Ameloblastic libroma affected 4 patients (three female and a male) with an age range of 19-56 years (median = 31, mean = 35). Three tumours (75”/) were in the mandible. Two patients had segmental resections, one had hemimandibulectomy and one declined further treatment after biopsy. No recurrence was recorded in the three cases treated during follow-up that ranged from 2 months to 4 years.

tumours:

a 15-year

review

from

Ibadan,

Nigeria

365

Other tumours

Other odontogenic tumours included three calcifying odontogenic cysts (2%), two cases each (2%) of calcifying epithelial odontogenic tumours, odontogenic fibroma and primary intraalveolar carcinomas and one each (1%) of ameloblastic fibrosarcoma and ameloblastic odontoma. The clinical and radiological features of these tumours were similar to those previously reported and their number was too small for analysis.

DISCUSSION

Available studies in the past on the relative incidence of odontogenic tumours are mostly in nonAfricans.1,2.1j,14.15Anand et aL6 and subsequently Mosadomil” reported that ameloblastomas were the most common histological type among Africans, explaining this occurrence by the ‘harvesting’ phenomenon in which patients with benign tumours, accumulated over the years, present en masse at newly established centres. Wu and Chan14 thought that the geographic variations in the incidence of tumours of the jaw might be partly the result of controversy about the terminology and classification of odontogenic tumours. In this study, odontogenic tumours accounted for 30% of all oral tumours biopsied excluding cysts, a relatively high incidence when compared with other studiesl.*J4 (Table 4). Odukoya,” in a recent study from Lagos, reported an incidence of 19%. The reason(s) for this persisting high incidence in this area must be further investigated. There was an almost equal sex incidence in the present series (M:F = 1.1: 1) which was similar to a previous report from NigerialO but in contrast to the female preponderance reported from Hong Kong14 and Michigan.’ This may be the result of the male preponderance among patients with ameloblastomas here.yJ6J7 The distribution of odontogenic tumours between the jaw bones is in keeping with previous reports from Nigeria.i0.“~‘8~‘9 This study confirms that ameloblastoma is the most common odontogenic tumour (59%) in this area.lOJ’ This compares with 62% in a series from Hong Kong14 but contrasts with studies among White people1,ZJ3 among whom odontoma seems to be the most prevalent odontogenic tumour (Table 4). The higher male prevalence among those with ameloblastoma in this study differs from the equal sex prevalence or higher female prevalence among white people.‘J5.*“.” As among whites and some Nigerian studies9J’.” ameloblastomas were sited more posteriorly than was originally reported7J for Nigerians. The suggested causative relationship with calculus deposits and sepsis7holds at best for posterior lesions where oral hygiene is more difficult. There is a need for further investigation into the real reason for the pattern of incidence at different sites.

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Journal

Table 4 -Percentage

of Oral

and Maxillofacial

incidence

Ameloblastoma Adenomatoid Odontogenic myxoma Ameloblastic - libroma - fibrosarcoma Calcifying epithelial cyst Calcifying epithelial tumour Central odontogenic tibroma Peripheral odontogenic libroma Ameloblastic fibro-odontoma Odontoma - compound complex Periapical cemental dysplasia Cementoma Number of cases

of odontogenic

Surgery tumours

Present study Ibadan

Mosadomi (Lagos)*O

59 13 16 3 1 2 2 2 1

66 7

128

7 29

7 3 -

Our finding that fibromyxoma is the second most common odontogenic tumour in this area confirms some previous studies.11J5J2However, there is an equal distribution between the mandible and maxilla in this study. Our finding of a higher female sex prevalence supports recent work. 11~15,** The mean age of 31 years is higher than the 25 and 24 years observed in two previous studies from Nigeria1rJ2 but compares with the 32 and 33 years reported elsewhere.23J4 Resection of the tumour with an adequate margin of normal (uninvolved) bone has been found to be adequate for most locally infiltrating tumours like ameloblastoma and tibromyxoma.‘7,25 Our treatment results agree with this view as the highest number of recurrent ameloblastomas occurred in the group treated by enucleation with trimming or saucerization or both. The rate of recurrence in this study might be underestimated as the median follow-up period was short and recurrences can develop as late as 30 years after operation.2Q7 Life time follow-up is advisable for ameloblastoma and fibromyxoma. Acknowledgements We thank Mr A. M. Sodiya and Mr Sayo Faloye for secretarial assistance and the entire staff of Cancer Registry University College Hospital. References 1, Regezi JA, Kerr DA, Courtney RM. Odontogenic tumours: Analysis of 706 cases.J Oral Surg 1978; 36: 771-778. 2. Daley TM, Wysocki GP, Pringle GA. Relative incidence of odontogenic tumours and oral and jaw cysts in a Canadian population. Oral Surg Oral Med Oral Path01 1994; 77: 276280. 3. Cook J, Singh P Tumours of the jaw. East Afr Med J 1956; 33: 383-390. 4. Dodge OG. Tumours of the jaw, odontogenic tissues and maxilla in Ugandan Africans. Cancer 1965; 18: 205-215. 5. Edington GM, Sheiham A. Salivary gland tumours and tumours of the oral cavity in Western Nigeria. Br J Cancer 1966; 20: 425437. 6. Anand SV, Davey WW, Cohen B. Tumours of the jaw in West Africa. Br J Surg 1967; 54: 901-917.

Wu and Chan (Hong Kong)14 62 4 1 0 0 2 4 4 1 6 2 17 82

Regezi et al. (Michigan)’ 11 3 3 2 0 2