Tumors and tumor-like growths arising from the odontogenic tissues constitute a heterogenous group of particularly interesting lesions, as they display the various inductive interactions that normally occur among the embryologic components of the developing tooth germ 1. In humans, tumors of odontogenic tissues are comparatively rare, comprising of about 1% of all jaw tumors 2. In children and adolescents, neoplastic lesions are often benign and are of mesenchymal origin 34. Choung and Kaban 5 were of the opinion that tumor histology in this age group did not correspond to their clinical behaviour.

There are few reports especially from Africa, which have specifically reported the high frequency of odontogenic tumors (OT) in children and adolescents in the literature. In most previous African reports, odontogenic tumours in children were presented as part of orofacial 3 or oral tumors in this age group 36; or presented as specific tumours e.g. ameloblastoma or adenomatoid odontogenic tumor 78. We could find only a single report on odontogenic tumors in children and adolescent in African environment 9. The aim of this study was to determine the relative frequency of odontogenic tumors among children and adolescent ≤ 19 years seen over a period of 24 years (1980–2003).

The histopathology records of the Department of Oral Pathology and Biology, College of Medicine, University of Lagos, Lagos, Nigeria, were reviewed for all the tumors and tumor-like lesions of the oral cavity and the jaws seen in children and adolescent ≤ 19 years from January 1980 to December 2003. Hematoxylin and eosin-stained sections was re-evaluated and the diagnosis in each case was confirmed or modified according to World Health Organization (WHO) 1992 classification 10. The data was subjected to analysis of age, sex, site of tumor and histopathologic type. The age of the patients was divided in four groups: Group 1 (0–5 years); group 2 (6–10 years); group 3 (11–15 years); group 4 (16–19 years). Data was analyzed using SPSS for Window (version 11.0; SPSS Inc., Chicago, IL) and frequency tables and cross tables were prepared.

A total of 477 tumors and tumor-like lesions were seen in patients ≤ 19 years during the period of the study. Of these, 92 (19.3%) were odontogenic tumors. Benign odontogenic tumors constituted 98.9% of the cases seen, while only 1 case (1.1%) of malignant variety was seen during the period. Table 1 shows the various histologic types and their relative frequency. There were 47 males and 45 females; a male-to-female ratio of 1:1 was observed. The mean (SD) age of patients was 14.9 (± 3.1) years (range, 4–19 years). Most of the patients (46.7%) were in age group 4 and the least number of patients were found in age group 1 (2.2%) Table 2.

Table 3 shows the gender and site distribution of various histologic typing of odontogenic tumors. The tumors occurred more often in the mandible (67) than in the maxilla (25) giving a maxilla-to-mandible ratio of 1:2.7.

Ameloblastoma constituted almost half (48.9%) of the odontogenic tumors with female-to-male and maxilla-to-mandible ratios of 1:1.7 and 1:8 respectively. The mean (SD) age of patients in this group was 15.1 (± 3.0) years (range, 4–19 years) with most patients (49%) in age group 3. Multicystic/solid and unicystic variants were diagnosed in 40 (89%) and 5 (11%) cases respectively.

Adenomatoid odontogenic tumor (AOT) was the second most common tumor in this series (Table 1) accounting for 19.6% of odontogenic tumors in this population. All the patients were between 8 and 19 years (Mean ± SD; 14.6 ± 3.2) with most of them (50%) in age group 4. More females (12) were affected than males (6); a male-to-female ratio of 1:2 was observed. Maxillary lesions (10) were commoner than mandibular lesions (8).

Odontogenic myxoma accounted for 8 cases (8.7%) of odontogenic tumors with a male-to-female ratio of 1:3. Only 1 case occurred in the maxilla, the rest (7) were found in the mandible. The patients were found between 10 and 19 years.

Odontogenic fibroma accounted for 7 cases (7.6%) of tumors in this series. More cases were found in males and in the mandible. Patients were seen between 5 and 19 years in this group.

Ameloblastic fibroma accounted for 5.4% of cases seen. The lesion occurred exclusively in the mandible with a male-to-female ratio of 1:4.

Odontomas accounted for 4.3% of OT seen. They were exclusively found in the maxilla with equal sex predilection.

Table 3 shows the gender and site distribution of other less common odontogenic tumors in children and adolescent ≤ 19 years of age.

We present a report of odontogenic tumours in children and adolescents aged ≤ 19 years. This report represents the largest series of odontogenic tumors in children and adolescents in Africa. We found that 19.3% of tumors and tumor-like lesions of the oral cavity and the jaws in children and adolescent in this study were odontogenic tumors. This is similar to the findings of Arotiba 6. However, other authors have reported higher 9111213 or lower 414 frequency of these heterogenous group of lesions in children and adolescents.

A major problem in comparing our report with previous studies is the lack of uniformty in the age group studied in those reports. Some studies were restricted to children under the age of 14 years 315, or 15 years 4611121316, while others included higher age groups 914. Odontogenic tumors were most frequently seen in patients in group 4 in this study (> 15 years) in agreement with Adebayo et al 9. Al-Khateeb et al 14 reported that odontogenic tumors were most commonly (72%) seen in patients aged 12–18 years in their report. Other authors have reported that odontogenic tumors were most frequently seen in patients aged 11–15 years 41113; these authors, however considered patients aged 0–15 years in their studies.

Odontogenic tumors were less frequently seen in patients aged 0–5 years in this study in agreement with most reports in the literature 491112131417. About 98% of OT in the present series was found in patients older than 5 years. Many odontogenic tumors are thought to arise from the tooth germ 18. In most permanent teeth, crown formation is completed by the age of 4 or 5 years; odontogenic tumors seemed to develop after crown formation 1213. This strengthens the impression that the majority of odontogenic tumors arise from quiescent remnants of the tooth germ 14.

Odontogenic tumors in children are known to have predilection for the mandible 111213. This is also corroborated by our findings with 73% of the tumors in this series found in the mandible. Al-Khateeb et al 14 however found 64% of OT in the maxilla. Odontomas were exclusively found in the maxilla in the present series. Males were slightly affected by OT in our study in agreement with Adebayo et al 11; whereas Ulmansky et al 4 reported female preponderance in their study.

Ameloblastoma was the most common tumor in this study in agreement with reports from Africa 611. Other authors reported odontoma as the most frequently seen OT in children 121314. Ulmansky et al 4 found odontogenic myxoma as the most common OT in children in their study. The gender and site distribution of ameloblastoma in this study is in agreement with other reports 611121314. Ameloblastoma was found in all the age groups considered in this study, unlike other histologic types of OT. Few cases of unicystic variant of ameloblastoma (11%) were seen in the present series. Unicystic ameloblastoma has been reported to be more common in Western children than African children 19. Previous data from Africa as corroborated by the present series, have shown a low percentage of unicystic ameloblastomas in their patient population compared to other parts of the World 2021. Unicystic tumors have a different prognosis to the multi cystic type and are said to be more common in children 192223.

Adenomatoid odontogenic tumor (AOT) was the second most common OT in this study and 50% of this tumor was found in patients >15 years. Asamoa 3 reported AOT as the most frequent pediatric odontogenic tumor in Nigeria; whereas Arotiba 6 found AOT as the second most common OT after ameloblastoma in Nigerian children. The relative frequency of 19.6% found in this study is higher than in other reports 691314. More of this lesion was found in the maxilla in concordance with previous reports 6792425. OT is reported to be more common in females 171726; and this is also confirmed by our findings.

In children, the reported incidence of myxoma ranges from 1.2% to 39% 46913. Myxoma was the third most common OT in this study with an incidence of 8.7%. Ulmansky et al 4 reported that odontogenic myxoma was the most common OT in Israeli children. The gender predilection favors females in previous publications 49242627. This study found that the male-to-female ratio was 1:3, in agreement with previous reports. Previous publications 92427 reported that both jaws were equally affected in their reports; a ratio of 1:7 was found in the maxilla and mandible respectively in the present study. Odukoya 26 also found maxilla-to-mandible ratio of 1:3.

Odontogenic fibroma was reported to be rare in children with incidence ranging from 0% to 1.3% of OT 491113. An incidence of 7.8% found in our study was however, similar to that of Al-Khateeb et al 14. Arotiba 6 reported that 12.5% of odontogenic tumors in his study were odontogenic fibroma. More cases were found in males and in the mandible in agreement with the report of Lu et al 17; whereas others 126 have reported females and maxillary predilection. Ameloblastic fibroma was exclusively seen in the mandible, accounting for 5.4% of OT seen in this study. Females were also affected more than males in the ratio of 1:4. Other authors 1726 have also reported predilection of ameloblastic fibroma for the mandible but with both jaws affected equally.

Odontomas are often regarded as dental hamartomas, rather than odontogenic neoplasms 142829. Odontoma is relatively rare in Nigerian children as confirmed in our report and others from Nigeria 6911, accounting for 4.3% of OT in this study. This contrasts the findings of Al-Khateeb et al 14, Tanaka et al 12 and Sato et al 13 that reported odontoma as the most frequently seen OT in North Jordanian and Japanese children respectively. Most odontomas are discovered on routine radiograph and do not produce clinical symptoms 1. This may be responsible for the low incidence observed in African population, because most patients in our environment do not seek medical consultation unless there are symptoms suggesting an obvious pathology. While some authors reported that odontomas commonly affect the mandible 1217, others have reported predilection for the maxilla 11314 and some authors have reported equal distribution in both jaws 91125. Odontomas were found exclusively in the maxilla in the present series.

Malignant odontogenic tumors are rare, most especially in children 146911121530. No cases of malignant odontogenic tumors were found in African children and adolescents 691130, Israeli children 4, North Jordanian children and adolescents 14 and Japanese children 1213. A case ameloblastic carcinoma of the mandible in a 16-year old girl was, however seen in this study.

Odontogenic tumors are relatively common in children and adolescents in Nigeria. One out of every 5 children and adolescents with tumor and tumor-like lesions of oral cavity and the jaws seen in this study had a diagnosis of odontogenic tumor.

The author(s) declare that they have no competing interests.

OFA conceived the study, coordinated the write-up and submission of the article, and also reviewed the slides.

ALL, WLA and MOO did the literature search and participated in the writing of the manuscript.

All the authors read and approved the final manuscript.

None declared