Paediatric Orofacial Tumours: New Oral Health Con- Cern in Paediatric Patients

SUMMARY Objective: This study aims to determine the incidence, age, gender, orofacial sites and histological pattern of paediatric orofacial tumours in a Nigerian population. The yearly findings will be analysed to identify the interval for increase in the incidence of paediatric oro-facial tumours. Patients and Methods: A 21-year (1990 to 2010) retrospective analysis of paediatric orofacial tumours in children younger than 16 years was carried out in the Results: Of the 1013 diagnosed lesions within the study period, there were 137 (13.5%) paediatric orofa-cial tumours, among which 71 (51.8%) cases occurred within the last 6 years (2005 to 2010). There was male predilection for the lesions (78 males to 59 females, ratio = 1.3:1). The mean age was 9 + 4.3 years, with peak age group of 11 to 15 years (n=60, 43.8%). The mandible (n=44, 32.1%), followed by the maxilla (n=42, 30.7%) and orofacial soft tissue (n=19, 13.9%) were the most common sites. The benign tumours (n=72, 52.6%) were slightly more than the malignant tumours (n=65, 47.4%). There were more malignant tumours (n=23, 16.8%) than benign tumours (n=20, 14.6%) within the last 3 years (2008 to 2010) under review. Burkitt's lymphoma (n=38, 27.7%) was the commonest malignant lesion. Conclusion: This study showed a recent increase in the incidence of paediatric orofacial tumours, particularly due to a higher incidence of Burkitt's lymphoma.


INTRODUCTION
Previous reports show that the incidence of paediatric orofacial tumours was relatively low, (9.1% to 10.7%).2][3] However, recent reports from Nigerian studies show an increasing incidence of paediatric orofacial tumours (24% to 28%) 4,5 in our environment.
A higher incidence of malignant orofacial tumours among paediatric patients is also reported among Nigerians by Ajayi et al4 in Lagos (13.3%) and Omoregie et al 6 in Benin (22.5%).Furthermore, Aregbesola et al 5 reported a higher incidence of malignant paediatric orofacial tumour (51%) than the benign tumours (49%).
Malignant lesions are a cause of oral health concern in children even with the current effort to control communicable diseases in the third world countries. 7In our environment they rank fourth as a cause of mortality. 8rofacial malignancies are of great concern because of the associated high mortality due to late presentation for treatment, 9,10 a low 5-year survival rate (55%), 11 poverty, lack of awareness and local beliefs. 12[15] So far, no study in our environment has evaluated the incidence of paediatric tumours with a view to determine if there is an increase incidence of these lesions over a given period.Also, the specific clinicodemographic factors and histological pattern of the lesions within a surge period is yet to be determined.This study aims to determine the incidence, age, gender, orofacial sites and histological pattern of paediatric orofacial tumours in a Nigerian population.It also aims to analyse the yearly findings in order to establish the incidence of the lesions during the study period.

METHODS
Ethical approval was obtained from the Hospital Ethical Committee to carry out a 21-year (1990 to 2010) retrospective analysis of all paediatric orofacial tumours seen in children younger than 16 years, in the Department of Oral Pathology/Oral Medicine, University of Benin Teaching Hospital, Benin City, Nigeria.This hospital serves as a major referral health centre in the south-south region of Nigeria and receives specimens from other hospitals in the city and parts of the South-East and South-West of Nigeria.
The incidence, age, gender, sites and histopathological patterns of paediatric orofacial tumours were obtained from the records of cases and histopathology registers.The histopathology slides of paediatric patients seen within the 21-year study period were reviewed.The data collected were analyzed using SPSS version 16 and statistical correlation of the variables was per-formed using Pearson's Chi-square, with a confidence level of 95% and probability values (p-value) of P<0.05 regarded as significant.

DISCUSSION
Several reports [1][2][3]16 between year 1996 and 2000 showed a relatively low incidence of paediatric orofacial tumours, which suggests that the lesions did not constitute great risk to oral health of children about a decade ago, compared to dental caries that was regarded as the highest oral health concern among paediatric patients. 17Recent studies among black African population shows an increasing incidence of malignant paediatric orofacial tumours, and has apparently raised oral health concerns for these population.18 This study was carried out among a population in the South-South zone of Nigeria and a similar pattern of increased incidence (13.5%) of paediatric orofacial tumours though relatively, with predilection for males and the jaws, and peak age range of 11 to 15 years was observed, especially within the last 6 years under review.
This study showed a predominant non-odontogenic paediatric orofacial tumour, with a narrowing of the gap between the incidence of benign tumours (52.6%) and malignant tumours (47.4%).Furthermore, a slight-ly higher incidence of malignant tumours (16.8%), compared to benign tumours (14.6%) was observed in the last 3 years (2008 to 2010) of the study.Burkitt lymphoma accounted mainly for the increase incidence of paediatric orofacial tumour observed within the last 6 years of the study, with a peak inci-dence in 2008.
Although a reduction in Burkitt lymphoma was observed in the last 2 years (2009 and 2010) of the study, the increase incidence of paediatric orofacial tumour in 2009 and 2010 were mainly due to ameloblastoma and diffuse non-Hodgkin lymphoma respectively.This study agrees with the recent report of a higher incidence of malignant paediatric orofacial tumours in our environment by Aregbesola et al. 5 On the contrary, a recent African study by Elarbi et al, reported a lower incidence of malignant paediatric orofacial tumour in Libyan children. 18herefore, the in-creasing incidence of malignant paediatric orofacial tumours and the attendant increase in oral health concerns appears not to be wide spread in Africa, but more pronounced in our environment.
The histopathologic pattern of the paediatric orofacial tumours studied showed that Burkitt's lymphoma was the commonest malignant lesion, while ameloblastoma was the commonest benign tumour.These tumours also accounted for most of the lesions within the 6-year surge period for paediatric orofacial tumours observed in this study.Similarly, previous studies [4][5][6]16 in our environment reported that Burkitt's lymphoma was the predominant malignant paediatric orofacial tumour.
It appears that the increase in oral health concerns for paediatric orofacial tumour in our environment may be primarily due to increase in the incidence of Burkitt's lymphoma.The reasons for this finding may not be unconnected with the poor control of infections by Epstein Barr virus (EBV) and plasmodium falciparum (malaria parasite), which are the two infections strongly associated with the pathogenesis of Burkitt's lymphoma. 19,20However, it was reported that funding to control malaria in sub-Saharan Africa has increased between 1999 and 2004. 21Apart from controlling repeated attacks of malaria, the molecular genetics of Burkitt's lymphoma need to be revisited.This is because the known sites of chromosomal translocation may not be the only sites where mutations in the Blymphocytes now occur.Furthermore, there are reports suggesting that variation in the pattern of chromosomal mutation in endemic and sporadic Burkitt's lymphoma 22, as well as the rapid accumulation of p53 protein in both EBV positive and negative B-lymphocytes 23,24 may be the other factors involved the development of Burkitt's lymphoma.
In our environment, other possible factors that may have contributed to increase in the incidence of paediatric orofacial tumours include; increase public awareness about oral health care and the establishment of more oral health care centres, with more specialist diagnosticians and improved diagnostic facilities for orofacial disease.
In conclusion, this study showed a recent increase in the incidence of paediatric orofacial tumours particu-larly in the jaws and among males, due to a higher incidence of Burkitt's lymphomas among other possible factors recognized in our environment.However, larger prospective studies are re-quired to determine if the finding in our Centre is applicable to the general paedi-atric population.This study suggests a higher oral health concerns for Burkitt's lymphoma among paedi-atric patients.We therefore recommend a more efficient utilization of the available funds for control of malaria infection, to help reduce the rapid rate of development of Burkitt's lymphoma in our environment.

Table 1
Age, gender and orofacial site distribution of paediatric orofacial tumours

Table 2
Histopathologic types of the paediatric orofa-

Table 3
Histopathologic types of the paediatric orofa-

Table 4
Distribution of the benign and malignant paediatric orofacial tumours by years

Table 5
Gender and orofacial sites distribution of paediatric orofacial tumour from 2005 to 2010

Table 6
Histopathologic types of paediatric orofacial tumour from 2005 to 2010 1