A multi-centre evaluation of malignant odontogenic tumours in Nigeria.

INTRODUCTION: odontogenic tumors originate from neoplastic transformation of the remnants of tooth forming apparatus. There are varying degrees of inductive interactions between odontogenic ectomesenchyme and epithelium during odontogenesis, leading to lesions that vary from benign to malignant. Malignant odontogenic tumours (MOTs) are very rare and are classified according to embryonic tissue of origin. Recently, there has been a few changes to the classification of MOTs according to the World Health Organization's (WHO) classification in 2017. This study aims to evaluate and reclassify MOTs, using a multi-centre approach in some major tertiary dental hospitals in Nigeria. METHODS: this study reviewed the clinicopathological data on 63 cases of MOT diagnosed over 25 years in five major tertiary dental hospitals in Nigeria. All MOT cases were reclassified according to the recent revision to the 2017 WHO classification of odontogenic tumours. RESULTS: from a total of 10,446 biopsies of oral and jaw lesions seen at the 5 study centres over the 25-year study period, 2199 (21.05%) cases were found to be odontogenic tumours (OTs), of which 63 were MOT. MOTs constituted 0.60% of the total biopsy cases and 2.86% of OTs. Odontogenic carcinomas presented with a mean age higher than odontogenic sarcomas. According to our 2017 WHO reclassification of MOTs, odontogenic carcinomas, ameloblastic carcinomas and primary intraosseous carcinomas were found to be the top three lesions, respectively. Carcinosarcomas were found to be extremely rare. CONCLUSION: using a multi-centre approach is a robust way to reduce diagnostic challenges associated with rare maxillofacial lesions such as MOTs.

A geographical analysis of ethnic distribution of jaw ameloblastoma in Nigerians.

INTRODUCTION: Ameloblastoma is the most common odontogenic tumour in Nigeria. A definite geographic variation has been observed in the frequency of odontogenic tumors from different parts of the world. However, there is no study on the regional variations in Nigeria. Hence, this study was designed to document the ethnic and geographical distribution of jaw ameloblastoma in Nigeria. METHODS: Archival data on ameloblastoma from 10 health facilities were obtained. Global Moran's I detected geographic clustering in its distribution while Local Getis Ord indicated the location of ameloblastoma clusters. Chi-square tested associations between variables at 0.05 level of significance. RESULTS: A total of 1,246 ameloblastoma cases were recorded in Nigeria. Besides substantial state variations, a South-North gradient was noticed in its distribution. Significant positive spatial autocorrelation was observed in the three major groups while ameloblastoma hotspots were found in the SouthWestern and Northwestern Nigeria. The Igbos had a higher prevalence of ameloblastoma outside their home region than within. CONCLUSION: The study hypothesized that the geographical distribution of ameloblastoma in Nigeria is the result of all or one of the following: the country's tropical climate, migration patterns and health seeking behavior. Hopefully, these claims should lead to further enquiry on the underlying causes.

Descriptive epidemiology of salivary gland neoplasms in Nigeria: An AOPRC multicenter tertiary hospital study.

OBJECTIVES: Accurate diagnosis of salivary gland neoplasms (SGN) in many centers in Africa is limited by poor diagnostic resources and ancillary services. Hence, we have carried out a multicenter epidemiological study to understand the true burden of SGN in Nigeria. METHOD: In this descriptive cross-sectional study, we have deployed resources available to members of the African Oral Pathology Consortium (AOPRC) to examine the burden of salivary gland lesions in Nigeria, using a multicenter approach. Data from seven major tertiary health institutions in northern, western, and southern Nigeria were generated using a standardized data extraction format and analyzed using the Epi-info software (Version 7.0, Atlanta, USA). RESULT: Of the 497 cases examined across the seven centers, we observed that SGN occurred more in females than males. Overall, pleomorphic salivary adenoma (PA) was found to be the most common. PA was found to be the commonest benign SGN while adenocystic carcinoma (ADCC) was the commonest malignant SGN. Regional variations were observed for age group, diagnosis, and gender distribution. Significant statistical differences were found between males and females for malignant SGNs (p-value=0.037). CONCLUSION: We found regional variation in the pattern of distribution of SGN in Nigeria. This is the largest multicenter study of SGN in Nigeria, and our findings are robust and representative of the epidemiology of this neoplasm in Nigeria.

Dermatofibrosarcoma protuberans: clinicopathologic presentation in Nigerians.

INTRODUCTION: Dermatofibrosarcoma protuberance (DFSP) is in general a rare low grade malignant sarcoma and possesses a tendency for local recurrence. It has a site predilection for the trunk. Occurrence in the facial area is extremely rare. Ample knowledge of its clinical, histological and biologic characteristics is vital for accurate and prompt recognition. METHODS: Over 13 years, clinicohistologic information of cases was retrieved. Histological and immunohistochemical re-evaluation were performed to re-confirm diagnosis. Data collected and analyzed with SPSS Statistics version 20 were presented as frequency tables, charts and proportions as appropriate. RESULTS: Of 191 soft tissue sarcomas, a total of 28 cases were diagnosed as DFSP (14.7%). Facial types occurred in 3 cases (1.6%). Tumour had age and site predilections for the 4th decade and trunk respectively. There was an equal gender distribution among cases. Most common clinical presentation was in form of painless protruding nodular mass. General histologic presentation revealed cellular lesions composed of spindle to oval neoplastic cells arranged in a storiform pattern. Mitotic figures were rare. All cases showed positive expressions to CD34. CONCLUSION: Facial DFSP is rare among Nigerians. Its clinical appearance may mimic other common benign lesions of the head and neck region often resulting in misdiagnoses. A comprehensive knowledge of its clinical and histologic presentations and biologic behavior, combined with its identification with the aid of advanced histologic and radiographic techniques results in prompt confirmatory diagnosis. Appropriate treatment should include adequate surgical excision techniques combined with adjuvant radiotherapy or chemotherapy.

A review of 640 Oral squamous cell carcinoma cases in Nigeria.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most prevalent malignant neoplasm in the oral cavity and accounts for 70% to 90% of all oral malignant neoplasms. The aim of this study was to examine the demographic distribution of OSCC in five Tertiary Health centres in Nigeria. MATERIAL AND METHODS: All cases diagnosed as OSCC during the period from 1970 -2014 were retrieved from the records of five teaching hospitals in Nigeria. Hematoxylin and eosin stained histological slides of all cases that had a diagnosis of OSCC were reviewed for confirmation and inclusion. Data from all the centers was collated at the University College Hospital, Ibadan by 2 researchers. The data was entered into and analyzed with the SPSS for Windows (version 20.0; SPSS Inc. Chicago, IL). Simple descriptive and comparative analyses were done, with the test of statistical significance set at p ≤ 0.05. RESULTS: A total of 640 cases of OSCC were seen out of 1560 oral malignant neoplasms representing 41% of all the oral malignancies seen. The mean age of occurence of OSCC was 55.5 (±17.0) years and a peak age incidence in the sixth and seventh decades of life. OSCC occurred more in males (60.9%) than females (39.1%) with a male: female ratio of 1.6:1. The well differentiated OSCC with 309 (48.3%) cases, was the most common grade, while the moderately differentiated and poorly differentiated OSCC accounted for 232 (36.2%) and 92 (14.4%) cases respectively. CONCLUSIONS: This study showed that OSCC is more common in males, most commonly seen in the 60-69 age group and the commonest site of occurrence was the mandibular mucosa. The well differentiated OSCC was the most common histology sub-type. Key words:Oral squamous cell carcinoma, tongue, palate, mandible.

Pattern of distribution of odontogenic tumours in sub-Saharan Africa.

OBJECTIVE: To analyse documented reports on odontogenic tumours (OTs) in sub-Saharan Black Africa and to create awareness of the need for more reports on this topic. METHODS: There were 2,186 African cases of OTs presented at the International Association of Oral and Maxillofacial Pathologists (IAOP) Congress (Cape Town, South Africa) in 1998 that were added to 2,198 cases derived from reports published in the scientific literature from 1998 to date. The analysis undertaken included frequency distribution of available data on OTs that was listed in the 2005 World Health Organization (WHO) classification. The chi-square test was applied as appropriate. RESULTS: A total of 4,384 cases of OTs from only 14 of 47 sub-Saharan Black African countries were analysed. Ameloblastoma was the OT most commonly reported, accounting for 74.2% of OTs (and 86.9% of category A OTs), followed by keratocystic odontogenic tumour (KCOT) (6.9%) and odontogenic myxoma (ODM) (4.9%). Malignant OTs were reported at a low frequency, of 1.4%. Nigeria contributed 38.7% of the cases of OT in this series. CONCLUSIONS: Ameloblastoma is the commonest OT in sub-Saharan Africa and has a higher occurrence in male than in female subjects. With data on OTs not available from 33 of 47 sub-Saharan African countries, additional reports are needed.

A retrospective review of 61 cases of adenomatoid odontogenic tumour seen in five tertiary health facilities in Nigeria.

INTRODUCTION: Adenomatoid odontogenic tumor (AOT) is a benign lesion originating from the dental lamina or its remnants. It is a relatively uncommon neoplasm representing about 3% of all odontogenic tumors. The aim of this study was to examine the clinical and radiological characteristics of AOTs in five major tertiary centres in Nigeria. METHODS: Archival hospital-based data stores of five tertiary health facilities in Nigeria were accessed. Case files and biopsy records were retrieved to obtain relevant information. Data was collected according to a proforma for standardization and entered into and analysed using SPSS for Windows (version 20.0; SPSS Inc. Chicago, IL). RESULTS: 61 (4.5%) cases of AOT were documented. The age range was 8-46 years with a mean age of 20.4±9.9 years. Male: Female ratio was 1:1.3. The anterior maxilla had 34 (55.8%) cases and the anterior mandible had 20 (32.8%) cases. 40 (65.6%) follicular cases, 20 (32.8%) extra-follicular cases and 1(1.6%) extra-osseous case were found. 31 cases (61.1%) were associated with impacted teeth and the upper canine was involved in 19 (57.6%) cases. CONCLUSION: This study showed AOT to be more common in the maxilla, more in females, most often associated with impacted canines, however, the suggestion of AOT being a "Two third tumour" was not observed in this study.

Desmoplastic ameloblastoma: analysis of 17 Nigerian cases.

OBJECTIVE: This study aimed to add to existing knowledge on 90 cases of desmoplastic ameloblastoma (DA) previously reported in the scientific literature and analyze data that could help speculate on its biologic profile. STUDY DESIGN: From 330 cases of ameloblastoma (pooled from 573 histologically diagnosed odontogenic tumours) 17 cases of DA were retrieved and analyzed for estimated mean growth rate (EMGR) and histologic variants. EMGR for DA was compared with EMGR for conventional ameloblastoma (CA), as recorded over the same period of 38 years. RESULTS: Desmoplastic ameloblastoma had predilection for mandible (81.2%), posterior mandible being the most commonly affected, contrary to scientific literature reports of anterior maxillary predilection. Simple DA (88.0%) and DA with osteoplasia (12.0%) were the histologic variants observed. EMGR for DA (0.36 ± 0.44 cm/mo) was significantly less than EMGR (0.71 ± 1.16 cm/mo) for CA (P = .000480). CONCLUSION: This study speculates that DA tends to be less biologically aggressive than CA and has predilection for posterior mandible in Nigerians.

Oral squamous cell carcinoma: a clinicopathologic review of 233 cases in Lagos, Nigeria.

PURPOSE: The aim of this study is to present the clinicopathologic characteristics of histologically diagnosed squamous cell carcinoma (SCC) of the oral cavity in Lagos, Nigeria, with a view toward analyzing the age, gender, site distribution, and histological differentiation. PATIENTS AND METHODS: All cases that were histologically diagnosed as SCC of the oral cavity between January 1995 and December 2005 were retrieved from the records of the Department of Oral Pathology and Biology, Lagos University Teaching Hospital and the Oral Pathology Service, Lagos State General Hospitals. All the cases were subjected to analysis of age, gender, site of occurrence, symptoms at presentation, and histological differentiation of tumors. RESULTS: Oral SCC constituted 10.8% (n = 233) of the 5,124 biopsy specimens obtained in all of the centers during the study period. The mean age (+/- standard deviation) of patients at presentation was 45.3 +/- 19.6 years (range, 3 to 86 years), with a male:female ratio of 1.4:1; 40% of these patients were under age 40 years. Peak incidence was found in the 20 to 29-year and 40 to 49-year age groups. Males were significantly younger than females (P = .00). Poorly differentiated SCC was the most common subtype (47.6%), followed by well-differentiated (32.6%) and moderately differentiated (19.7%) subtypes. The mandibular gingiva was the most commonly affected site (31.8%), followed by the maxillary gingiva (23.3%) and tongue (17.6%). The least commonly affected site was the floor of the mouth. CONCLUSIONS: Oral SCC is most common in the mandibular gingiva and in males in our environment, with 40% of cases occurring in patients under age 40 years. The poorly differentiated subtype is the most common histological differentiation.

Malignant orofacial neoplasms in children and adolescents: a clinicopathologic review of cases in a Nigerian tertiary hospital.

OBJECTIVE: The aim of the study was to determine the relative frequency of orofacial malignant neoplasm in children and adolescents. METHODS: A retrospective review of malignant orofacial tumours in children and adolescents