Odontogenic tumours: a retrospective study of 1642 cases in a Chinese population

Clinicopathologic and imaging features of odontogenic myxomas: a multi-institutional study

PURPOSE

This study aims to report clinicopathologic and imaging features of odontogenic myxomas (OM), highlighting uncommon findings.

METHODS

Clinicopathologic and imaging data of OMs diagnosed in the five Brazilian diagnostic pathology centers were collected and analyzed.

RESULTS

The series comprised 42 females (68.9%) and 19 males (31.1%), with a 2.2:1 female-to-male ratio and a mean age of 34.5±15.4 years (range: 4-80). Clinically, most OMs presented as painless intraoral swelling (n = 36; 70.6%) in the mandible (n=37; 59.7%). Multilocular lesions (n=30; 83.3%) were more common than unilocular lesions (n=6; 16.7%). There was no statistically significant difference between the average size of unilocular and multilocular OMs (p=0.2431). The borders of OMs were mainly well-defined (n=24; 66.7%) with different degrees of cortication. Only seven tumors caused tooth resorption (15.9%), while 24 (54.5%) caused tooth displacement. Cortical bone perforation was observed in 12 (38.7%) cases. Morphologically, OMs were characterized mainly by stellate or spindle-shaped cells in a myxoid background (n=53; 85.5%). Surgical resection was the most common treatment modality (n=15; 65.2%), followed by conservative surgery (n=8; 34.8%). Outcomes were available in 20 cases (32.3%). Seven of these patients had local recurrence (35%). Enucleation was the treatment with the highest recurrence rate (4/7; 57.1%).

CONCLUSIONS

OM has a predilection for the posterior region of the jaws of female adults. Despite their bland morphological appearance, they displayed diverse imaging features. Clinicians must include the OM in the differential diagnosis of osteolytic lesions of the jaws. A long follow-up is needed to monitor possible recurrences.

Retrospective analysis of odontogenic myxoma and odontogenic myxofibroma in the oral and maxillofacial region: a fibrous tissue-related differentiation

The clinical differences between odontogenic myxoma (OM) and odontogenic myxofibroma (OMF), and the clinical significance of their classifications, remain unclear. This study reviewed the clinicopathological characteristics of patients with OM or OMF and evaluated the fibrous component of the specimens. Medical records of 21 patients with OM or OMF who underwent tumour resection were reviewed. The percentage of fibrous tissue on the representative sections was evaluated using haematoxylin and eosin- and Masson's trichrome-stained specimens. Histopathological diagnoses included 11 OMs and 10 OMFs with no tumour recurrence except for two cases in which the dredging method was applied. More cortical bone perforation was observed in OM than in OMF cases, without significant differences. Location-locularity and apparent diffusion coefficient value (ADC)-cortical bone perforation were significantly correlated in all OM and OMF cases. The percentage of fibrous tissue in specimens showed bimodal distribution bordered by 45%. There was a significant association between diagnosis based on 45% fibrous tissue criterion and the final pathological diagnosis. Our study showed a tendency for cortical bone perforation in OM compared to OMF and correlation between ADC and cortical bone perforation. According to the histopathological analyses, the fibrous component of each case was bimodal with 45%, which may be a criterion to distinguish between OM and OMF. Accumulating knowledge, such as significant differences in prognosis, may allow for minimal surgical treatment options based on the diagnosis according to this novel histopathological criterion.

Molecular pathogenesis of ameloblastoma

Ameloblastoma (AM) is a benign, although aggressive, epithelial odontogenic tumour originating from tooth-forming tissues or remnants. Its aetiopathogenesis remains unclear; however, molecular analysis techniques have allowed researchers to progress in understanding its genetic basis. The high frequency of BRAF p.V600E as a main driver mutation in AM is well established; nevertheless, it is insufficient to explain its tumourigenesis. In this review, we aimed to integrate the current knowledge about the biology of AM and to describe the main genetic alterations reported, focusing on the findings of large-scale sequencing and gene expression profiling techniques. Current evidence shows that besides BRAF mutation and activation of the MAPK pathway, alterations in Hedgehog and Wnt/β-catenin pathway-related genes are also involved in AM pathogenesis. Recently, a tumour suppressor gene, KMT2D, has been reported as mutated by different research groups. The biological impact of these mutations in the pathogenesis of AM has yet to be elucidated. Further studies are needed to clarify the impact of these findings in the identification of novel biomarkers that could be useful for diagnosing, classifying, and molecular targeting this neoplasm.

Frequency and Demographic Analysis of Odontogenic Tumors in Three Tertiary Institutions: An 11-Year Retrospective Study

Odontogenic tumors (OTs) are distinct conditions that develop in the jawbones, exhibiting diverse histopathological features and variable clinical behaviors. Unfortunately, the literature on this subject in Saudi Arabia remains sparse, indicating a pressing need for more comprehensive data concerning the frequency, demographics, treatment modalities, and outcomes of OTs.

OBJECTIVES

The study aims to evaluate the frequency, demographic features, treatment, and outcomes of OTs across three tertiary medical centers.

METHODS AND MATERIAL

OT cases were identified in King Abdulaziz Medical City (KAMC), King Fahad Medical City (KFMC), and Prince Sultan Military Medical City (PSMMC) from January 2010 to December 2021.

RESULTS

Ninety-two OT cases were identified from the anatomical pathology laboratories of three tertiary hospitals. KFMC contributed the highest number of cases (43.5%), followed by KAMC (30.4%) and PSMMC (26.1%). The median age of OT patients was 29 years (range: 5-83), with males representing more than half of the patients (56.5%). The mandible was the most frequent site of OT occurrence (72.5%), with ameloblastoma being the predominant OT (63.0%), followed by odontoma (19.5%). Among the treatment modalities, bone resection was employed the most (51.0%), followed by enucleation (25.6%). Notably, 11.5% of OT cases with available follow-up data exhibited recurrence, with ameloblastoma accounting for eight recurrent cases.

CONCLUSIONS

Although OTs are relatively common in the jaws, they are rare in anatomical pathology laboratories and the general population. This study contributes valuable insights into the epidemiology characteristics, treatment trends, and recurrence rates of OTs in Saudi Arabia.

Unicystic ameloblastoma: A retrospective study on recurrent factors from a single institute database

OBJECTIVE

Unicystic ameloblastomas are a variant of ameloblastoma with a definite recurrence rate because of the biological behaviours of the tumour. The risk factors associated with disease recurrence were analysed in this retrospective study.

METHODS

A total of 132 patients with primary unicystic ameloblastoma reported in a tertiary hospital from 2005 to 2015 were analysed to identify the clinic-pathological and radiological factors associated with recurrence using univariate and multivariate Cox regression analyses.

RESULTS

The mean volume was 30.54cm3 ± 12.55 cm3, and this value differed significantly according to recurrence (p < 0.001). Root resorption and bone cortex/soft tissue invasion were also significantly associated with recurrence among unicystic ameloblastoma patients (p = 0.017 vs. p < 0.001, respectively). A new stage classification system was developed to predict disease recurrence of patients. The multivariate Cox regression analysis revealed that the new stage classification system was the only predictor of disease recurrence in unicystic ameloblastoma patients (p < 0.001), regardless of root resorption, position and site characteristics.

CONCLUSIONS

Volume, root resorption and bone cortex/soft tissue invasion were risk factors for disease recurrence among unicystic ameloblastoma patients. The new stage classification was an independent predictor of disease recurrence in patients with unicystic ameloblastoma.

Ameloblastic Carcinoma of the Maxilla With Uncommon Sinus Manifestations

Ameloblastic carcinoma (AC) represents a distinct challenge in the realm of odontogenic malignancies due to its rarity and aggressive nature. We present a unique case of AC in a 70-year-old male, retired dry cleaner, with symptoms initially suggestive of chronic allergic rhinitis and recurrent acute sinusitis with asymmetric facial edema and paresthesia. Detailed evaluation revealed a prominent mass in the right maxillary sinus with extensive cortical destruction. Pathological assessment post-right maxillectomy identified a high-grade AC with malignant spindle cell transformation. The patient underwent subsequent interventions, including neck dissection and radiation therapy. Twelve months post-presentation, the patient was recovering appropriately without evidence of recurrence of malignancy. This case highlights the diagnostic challenges posed by AC as well as its unique presentations emphasizing the importance of a comprehensive approach and multidisciplinary management. It also raises considerations about potential chemical exposure implications in AC development.

Ameloblastic carcinoma: A systematic review

BACKGROUND

Ameloblastic carcinoma (AC) is the most common odontogenic malignancy, constituting approximately 30% of cases in this category. Literature is sparse on malignant odontogenic neoplasms, with a large proportion of current knowledge derived from case reports or small case series.

METHODS

A systematic review of case series/case reports of AC was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Statement guidelines. Demographic and clinical information, including duration of the lesion, location, clinical presentation and radiologic features, were analysed. Additionally, the origin of the lesion (primary/secondary), Ki-67 proliferation index, treatment performed, metastasis, tumour recurrence and prognosis were collected for analysis.

RESULTS

A total of 126 studies, including 285 individual cases of AC, were included in this review. Patients presented with a near-equal distribution of painless and painful swellings. ACs presented at a median age of 45 years, with a male-to-female ratio of 1:2. The mandible was most frequently involved, with rare cases extending to involve more than one region, including crossing the midline. Although most lesions presented with poorly-demarcated borders (52.6%), unilocular lesions with well-demarcated borders (47.4%) comprised a substantial number in the sample. The proliferation index was only reported in 27 cases, with a mean score of 42% and a wide range. The probability of tumour recurrence increased, and the survival probability decreased with prolonged follow-up duration.

CONCLUSION

This study provides more comprehensive, up-to-date descriptive data on these rare odontogenic malignancies, aiding clinicians and Pathologists with the diagnosis and surgeons in their management of cases.

Clinical outcome following conservative treatment of 58 mandibular ameloblastoma patients: a retrospective study

The aim of this study was to retrospectively analyze the surgical outcome of the patients with mandibular ameloblastoma (MA) with intact inferior cortex and the lingual cortex of the mandible, treated with conservative management in the form of enucleation with peripheral ostectomy, mechanical curettage, chemical cauterization, dredging, and marsupialization. The patients were included with the diagnosis of MA between the age group of 14 to 60 years with their computed tomography (CT) scans showing intact inferior cortex and the lingual cortex of the mandibular walls. Out of 96 cases of ameloblastoma, 58 (61%) were in mandible and 38 (39%) cases in maxilla. We analyzed these 58 patients retrospectively which were operated conservatively between January 2009 and December 2018. The treatment protocol for all the solid variants and the unicystic variants with intact buccal, inferior, and the lingual cortex was enucleation with peripheral ostectomy followed by mechanical curettage, chemical cauterization, and subsequent dredging. This was performed in 90% (n = 52) cases, whereas the treatment protocol for unicystic variants with perforated buccal cortex and intact inferior and lingual cortex was marsupialization followed by the enucleation with peripheral ostectomy, mechanical curettage, chemical cauterization, and subsequent dredging which was performed in 10% (n = 6) cases. Chi square test was applied to the effectiveness of conservative management as outcome variable. The new bone formation along with bony trabeculae was found in 96.6% (n = 56) of the cases. Recurrence was noted in 3.44% (n = 2) of the cases. A p value was 0.001, thus suggesting statistically highly significant result. On the basis of present study, though we can conclude that the MA with the intact inferior and the lingual cortex can be managed effectively with conservative treatment with long term regular follow up, still we would caution that the reader must use their best clinical judgement based on latest available data. For some patients, returning to clinic frequently and undergoing multiple minor procedures may not be suitable to be considered the best, whereas resection and reconstruction may be deemed more appropriate.

Pediatric Odontogenic Tumors

Odontogenic tumors are rare tumors of the jaws that arise from remnants of the tooth forming apparatus. Some odontogenic tumors demonstrate strong predilection for pediatric patients including the unicystic ameloblastoma, adenomatoid odontogenic tumor, ameloblastic fibroma, ameloblastic fibro-odontoma, odontoma, and primordial odontogenic tumor. In this review, we discuss the clinical, radiographic, histopathologic, and molecular characteristics of select odontogenic tumors that demonstrate pediatric predilection and review management.

Analysis of the 100 most cited articles on ameloblastoma

OBJECTIVES

An increasing number of articles are published each year. The aim of this is to provide a list of the 100 most cited articles on the subject of ameloblastoma.

METHODS

A bibliographic search was performed on Google Scholar (GS), Microsoft Academic (MA), and Dimensions for ameloblastoma. A ranking was created in order of citation density. Graphical representations of keywords and authorship were created with VOSviewer. Statistical analysis was performed and only results with a 95% confidence interval were considered significant.

RESULTS

A helpful list of top 100 articles was developed to help professionals in a variety of ways. Some curiosities are discussed about this scientometric analysis in ameloblastoma articles.

CONCLUSIONS

A useful list of the top 100 most cited articles on ameloblastoma has been provided. Bibliometric and altmetric analysis using Google Scholar, Microsoft Academic, and Dimensions is a free and excellent tool, not only as a citation manager but also as a study reference.

Metastasising ameloblastoma or ameloblastic carcinoma? A case report with mutation analyses

BACKGROUND

Ameloblastic carcinoma and metastasising ameloblastoma are rare epithelial odontogenic tumours with aggressive features. Distinguishing between these two lesions is often clinically difficult but necessary to predict tumour behaviour or to plan future therapy. Here, we provide a brief review of the literature available on these two types of lesions and present a new case report of a young man with an ameloblastoma displaying metastatic features. We also use this case to illustrate the similarities and differences between these two types of tumours and the difficulties of their differential diagnosis.

CASE PRESENTATION

Our histopathological analyses uncovered a metastasising tumour with features of ameloblastic carcinoma, which developed from the ameloblastoma. We profiled the gene expression of Wnt pathway members in ameloblastoma sample of this patient, because multiple molecules of this pathway are involved in the establishing of cell polarity, cell migration or for epithelial-mesenchymal transition during tumour metastasis to evaluate features of tumor behaviour. Indeed, we found upregulation of several cell migration-related genes in our patient. Moreover, we uncovered somatic mutation BRAF p.V600E with known pathological role in cancerogenesis and germline heterozygous FANCA p.S858R mutation, whose interpretation in this context has not been discussed yet.

CONCLUSIONS

In conclusion, we have uncovered a unique case of ameloblastic carcinoma associated with an alteration of Wnt signalling and the presence of BRAF mutation. Development of harmful state of our patient might be also supported by the germline mutation in one FANCA allele, however this has to be confirmed by further analyses.

Papilliferous Keratoameloblastoma: Systematic review

Papilliferous keratoameloblastoma (PKA) is a rare entity, and not much is known about its clinicodemographic features or biological nature. This review aimed to provide clarity regarding the characterisation of the demographic, clinical, radiological and histopathological features of PKA. Case reports of PKA were identified through a systematic search across multiple databases. The search yielded a total of 10 cases, half of which were of Indian origin. All the cases invariably occurred in the mandibular posterior region and involved the right side; only one case primarily involved the left side of the mandible. PKA should be considered a variant of the conventional ameloblastoma that is towards the more aggressive end of the spectrum. It tends to occur in older individuals (in their fifth decade or older), with a marked propensity to occur in the right mandibular posterior region. Surgical resection with diligent follow-up is warranted in the treatment of PKA.

Ameloblastoma of the jaws in adult: A retrospective review of local recurrent lesions based on the resection margin in the adjacent apparent healthy tissues

Background

The surgical treatment of ameloblastoma of the jaws remains contentious due to the variable recurrence rate amongst its variants, the tumor's local invasive behavior, and the lack of consensus among surgeons concerning the extent of resection in the contiguous healthy tissues.

Objective

To determine the recurrence rate of ameloblastoma and its association with the resection margins.

Materials and methods

This is a retrospective cohort study of the medical records of patients who underwent surgical resection of the jaws as the primary modality of treatment for ameloblastoma. Clinical data over the 26 years were analyzed for age, gender, site of the lesion, size, radiographic appearance, histopathological sub-type, and the incidence of recurrence post-treatment. Descriptive and bivariate statistics were computed.

Results

A retrospective audit of 234 cases was included in the study that was typical (solid/multicystic) ameloblastoma. The age of patients ranged from 20 to 66 years with a mean age of 33.4 ± 9.6 years, and a male-to-female ratio of 1.2: 1 (P = 0.52). The follicular and plexiform types accounted for the majority of histopathological variants (89.8%; P = 0.000). Overall, 6.8% of cases relapsed after the initial primary surgery. The rate of recurrence was high with a resection margin of 1.0 or 1.5 cm than 2.0 cm (P = 0.001). No case of recurrence was seen with a resection margin of 2.5 cm margin.

Conclusion

A low recurrence rate of 6.8% was noted in our series of cases. A wide 2.5 cm resection margin is recommended in the adjacent healthy tissues.

Ameloblastic carcinoma of the mandible: a case report

BACKGROUND

Ameloblastic carcinoma is a malignant form of ameloblastoma and a very rare odontogenic tumor. We report a case of ameloblastic carcinoma that occurred after removal of a right-sided mandibular dental implant.

CASE PRESENTATION

A 72-year-old female patient visited her family dentist with a complaint of pain around a lower right implant placed 37 years previously. Although the dental implant was removed with the diagnosis of peri-implantitis, the patient experienced dullness of sensation in the lower lip and was followed up by her dentist, but after no improvement. She was referred to a highly specialized institution where she was diagnosed with osteomyelitis and treated the patient with medication; however, there was no improvement. In addition, granulation was observed in the same area leading to a suspicion of malignancy, and the patient was referred to our oral cancer center. The diagnosis of squamous cell carcinoma was made after a biopsy at our hospital. Under general anesthesia, the patient underwent mandibulectomy, right-sided neck dissection, free flap reconstruction with an anterolateral thigh flap, immediate reconstruction with a metal plate, and tracheostomy. Histological analysis of the resected specimen on hematoxylin and eosin staining showed structures reminiscent of enamel pulp and squamous epithelium in the center of the tumor. The tumor cells were highly atypical, with nuclear staining, hypertrophy, irregular nuclear size, and irregular nuclear shape, all of which were suggestive of cancer. Immunohistochemical analysis showed that Ki-67 was expressed in more than 80% of the targeted area, and the final diagnosis was primary ameloblastic carcinoma.

CONCLUSION

After reconstructive flap transplantation, occlusion was re-established using a maxillofacial prosthesis. The patient remained disease-free at the 1-year 3-month follow-up.

Intraosseous carcinoma of the anterior maxilla identified as the occult primary tumour of carcinoma of unknown primary

Carcinoma of unknown primary (CUP) is defined as lymph node metastasis without a detectable origin until after the initial treatment has been performed. The most common occult primary site in the head and neck, as revealed by a review of the published literature, is the oropharynx. An occult primary site in the oral region is extremely rare. We report a rare case of head and neck CUP (HNCUP) in a 69-year-old female patient, wherein the occult primary lesion was a primary intraosseous carcinoma (PIOC) invading the anterior maxilla. During the course of the initial diagnostic workup, no primary lesion could be identified; however, cervical lymph node metastasis to left levels IB and IIA were observed in the patient. A neck dissection followed by adjuvant radiotherapy was performed. However, the PIOC of the anterior maxilla was identified 6 months after neck treatment and was confirmed as the occult primary tumour of the HNCUP. This case is quite rare and required a comprehensive workup to guide optimal treatment. Careful follow-up or active biopsy should be considered if osteolytic changes are observed in the jaw.

Immunohistochemical expression of E-cadherin, N-cadherin and Snail/slug in ameloblastoma

CONTEXT

Ameloblastoma is the most common odontogenic tumour and its histomorphological distinction into growth patterns and variants, does not accurately convey information about its biologic aggressiveness. Expression of epithelial mesenchymal transition (EMT) markers, which have been implicated in its etiogenesis, might assist in delineating aggressiveness across variants. This may help in formulating appropriate treatment modalities for its management AIMS: To determine expression of SNAIL/SLUG and ECAD/NCAD in tumour cells in clinical and histological subtypes of ameloblastoma and to establish any association between the immunostaining profile and the biologic behaviour of histologic types of ameloblastoma.

SETTINGS/DESIGN

This is a retrospective study conducted to evaluate the immunoprofile of selected clinical subtypes and histological variants to EMT factors via immunostaining to SLUG and ECAD/NCAD antibodies. Mean aggregate scores for each antibody per variant was analyzed using ANOVA or Kruskal-Wallis test when appropriate. Agreement between AR and SR regions was correlated using Spearman's correlation co-efficient.

RESULTS

A higher staining SLUG intensity in the stellate reticulum (SR) like areas relative to the ameloblast like areas (AR) was observed, without concomitant E-cadherin repression or elimination. However, a direct relationship between SLUG and N-cadherin was observed.

CONCLUSION

Expression of SLUG in the SR like areas can be utilized to predict the biologic behavior of specific clinico-histological variants, however its mechanism via alterations in cadherin switching is equivocal.

Characteristics, Diagnosis and Treatment of Compound Odontoma Associated with Impacted Teeth

Compound odontoma is a malformation typical of young adults below the age of 20, with a slight preference for the male gender and the anterior region of the maxilla. Clinically asymptomatic, it can be detected during a radiological investigation in connection with the persistence of deciduous dental elements and the impaction of definitive ones. The treatment of choice is excisional surgery and recurrence is a rare event. The need for orthodontic therapy for impacted elements is usually not necessary because in most cases, odontomas are small, circumscribed lesions the size of a permanent tooth. In this article, the diagnostic and therapeutic surgical excision procedure is presented in three patients at developmental age with large compound odontomas associated with at least one retained canine, and in two of the cases, with serious transmigration to the impacted tooth elements.

Malignant odontogenic tumors. A report of a series of 30 cases and review of the literature

Malignant odontogenic tumors are rare entities and can arise de novo or from malignant transformation of pre-existing lesions. The aim of the present study was to report 30 cases of malignant odontogenic tumors diagnosed at a single diagnostic center over a 38-year period.

MATERIALS AND METHODS

All cases of malignant odontogenic tumors diagnosed between 1980 and 2018 were retrieved from the files of the School of Dentistry, University of Buenos Aires; their frequency and clinical, radiographic, and histopathological features were analyzed. The obtained data were compared with the information reported in the literature.

RESULTS

Malignant odontogenic tumors accounted for 2 % of odontogenic tumors and 0.05 % of all oral-maxillofacial diseases. Mean age was 43 years (8 to 87 years). No differences in sex distribution were observed. The most frequent location was the mandible, mostly the posterior mandibular body and the ramus. Odontogenic carcinomas were the most frequent tumors, and primary intraosseous carcinomas were the most common in this group.

CONCLUSIONS

This is the largest case series of malignant odontogenic tumors diagnosed at a single center reported in the literature to date. Diagnosis of these tumors is challenging based on their rarity and complexity and relies on careful analysis of the histopathological, clinical, and radiographic features.

Ameloblastoma: An Updated Narrative Review of an Enigmatic Tumor

Ameloblastoma is one of the most common benign odontogenic tumors of the jaw that constitutes about 10% of all tumors that arise in the mandible and maxilla. It is a slow-growing but locally invasive tumor that presents with painless swelling of the mandible or maxilla. The World Health Organization (WHO) classification of 2017 describes ameloblastomas of the following four types: ameloblastoma; unicystic ameloblastoma; extraosseous/peripheral ameloblastoma; and metastasizing ameloblastoma. The diagnosis of ameloblastoma requires computerized tomography (CT) imaging as well as a biopsy. A biopsy is helpful in differentiating ameloblastoma from ossifying fibroma, osteomyelitis, giant cell tumor, cystic fibrous dysplasia, myeloma, and sarcoma. The best treatment of ameloblastoma is aggressive en bloc resection with simultaneous reconstruction. The high recurrence rate and large tissue defects have been long-standing issues in the treatment of ameloblastoma. Recent molecular developments strongly suggest the possibility of targeted therapy with better outcomes in ameloblastomas. We present a detailed updated narrative review of our current understanding and management of this enigmatic tumor.

The Efficiency of a Learning Software Compared to e-Books in Dental Education

OBJECTIVES

 Due to time-consuming curricular and extracurricular activities, students in dentistry and medicine can profit from efficient learning strategies. One strategy could be the preparation with individually designed educational software that embed different multimedia sources. The aim of this study was to determine the efficiency of such a program compared with an e-book similar to a traditional textbook.

MATERIALS AND METHODS

 Dentistry students of the Johannes Gutenberg-University of Mainz passed an entrance multiple-choice test on the topic of odontogenic tumors and were then randomized into two groups. Afterward, both groups had 14 days to study on the topic of odontogenic tumors either with a learning software or an e-book. A final exam was then taken and the two groups were compared.

STATISTICAL ANALYSIS

 A least significant difference post hoc analysis comparing the group average values was performed. The level of significance was p <0.05.

RESULTS

 Seventy-one students took part in the study. While students from the first and second clinical semester showed significantly better results and improvements with the e-book, an opposite effect was observed in students from the third and fifth clinical semester with significantly better results and improvements with the software.

CONCLUSION

 Depending on the clinical experience and knowledge, a multimedia educational software can help students in dentistry to enhance efficiency in the preparation for exams.

Effectiveness of the Conservative Surgical Management of the Ameloblastomas: A Cross-Sectional Study

Ameloblastoma is a benign, but locally aggressive odontogenic neoplasm, whose appropriate therapeutic management remains highly debatable. The aim of this study was to evaluate the reliability and effectiveness of the two conservative surgical therapeutic protocols (curettage with peripheral ostectomy only and curettage plus cryotherapy) for the management of ameloblastomas. About 53 cases of the ameloblastomas treated in 9 years were retrospectively analyzed regarding their clinical, histopathologic, radiographic, and therapeutic data. The results and the postoperative complications related to both the therapeutic protocols were also statistically investigated. A slight female preponderance was seen (1.12:1.0) with a mean age of 27.1 years. The posterior mandible was the most affected site and dental involvement was frequently found. Multilocular lesions causing the alterations of the bone cortices were the most common radiographic findings. Recurrences were seen in 9.4% of the cases and although the patients submitted to curettage plus cryotherapy have shown an increased incidence of wound dehiscence, infection, and paresthesia, only bone sequestration proved to be significantly more frequent in this group compared to the patients treated by curettage with peripheral ostectomy only. The incidence of the recurrences following the conservative management is low and cryotherapy use as an adjuvant tool must be rationally considered.

Frequency of Odontogenic Tumors: A Single Center Study of 1089 Cases in Japan and Literature Review

Several attempts have been made to classify odontogenic tumors; however, the need for a uniform international classification system led the World Health Organization (WHO) to present a classification of odontogenic tumors in 1971. We aimed to evaluate the number and types of odontogenic tumors examined at the Tokyo Dental College Hospital in Japan to determine the frequency and types of odontogenic tumors, based on the 2017 WHO classification system, as this information has not been reported previously in Japan. We also compared the results of our evaluation with those reported in previous studies. We conducted a clinicopathological evaluation of odontogenic tumors examined at the Tokyo Dental College Hospital between 1975 and 2020. This included an analysis of 1089 cases (malignant, n = 10, 0.9%; benign, n = 1079, 99.1%) based on the 2017 World Health Organization Classification of Head and Neck Tumors. We identified 483 (44.3%), 487 (44.7%), and 109 (10.0%) benign epithelial odontogenic, mixed odontogenic, and mesenchymal tumors, respectively. The most common tumor types were odontoma (42.5%) and ameloblastoma (41.9%). Of the 1089 cases, 585 (53.7%) and 504 (46.3%) were male and female patients, respectively. Ameloblastoma and ameloblastic fibroma occurred more commonly in male patients, whereas odontogenic fibroma and cemento-ossifying fibroma affected female patients primarily. The age at diagnosis ranged from three to 87 (mean, 29.05) years. In 319 (29.3%) patients, the age at diagnosis ranged from 10 to 19 years. Ameloblastoma and odontoma were the most common tumor types among patients in their 20s and those aged 10-19 years, respectively. In 737 (67.7%) and 726 (66.7%) patients, the tumors were located in the mandible and posterior region, respectively. Ameloblastoma was particularly prevalent in the posterior mandible. Odontogenic tumors are rare lesions and appear to show a definite geographic variation.

Malignant Ameloblastoma with Hepatic Metastasis in a 38-Year-Old Haitian Woman

BACKGROUND Primary malignant ameloblastoma is a very rare tumor of the dental lamina epithelium. Similar to the benign ameloblastoma, the mass is without significant histological atypia, but the malignant type may present with metastases, most commonly to the lungs. The average age of diagnosis is 34 years, and the malignancy affects men and women equally. The tumors often present with an insidious growth and have a median survival from time of diagnosis of 17.6 years. Due to the rarity of this lesion, a standard of care has not yet been established. CASE REPORT A 38-year-old Haitian woman, who initially presented with a large primary malignant ameloblastoma of the angle of the mandible, experienced a recurrence in the floor of the mouth 30 months after surgical resection. In 2018, 2 years after the removal of the recurrent tumor, the patient presented with ascites, right-sided abdominal pain, weight loss, and a palpable liver mass. Laparoscopic exploration demonstrated a complex lateral right liver lobe cyst, suspicious for parasitic infection. Cytological analysis showed positive staining for cytokeratin 5/6, P63, and CD56, indicative of metastatic ameloblastoma of the liver. Consistent cell morphology from the primary tumor and liver cyst was also noted. Following drainage of the cyst, the patient returned to Haiti, where she died in 2020. In Haiti, she lacked appropriate local medical care, leading to the severe progression of her initial primary ameloblastoma and disease recurrence. CONCLUSIONS Malignant ameloblastoma accounts for less than 2% of all odontogenic tumors, as the benign variant is much more common. Distant metastases of these lesions are rare; to date, few cases have presented with hepatic metastases.

Clinico-pathological study of malignant odontogenic tumours from a national referral centre

BACKGROUND

Malignant odontogenic tumours are extremely rare tumours occurring within the jaws. Our study was performed to determine the demographic and clinico-pathological features of malignant odontogenic tumours amongst a multi-ethnic Asian population.

METHODS

This was a retrospective cross-sectional study of malignant odontogenic tumours diagnosed at the Institute for Medical Research, Malaysia, from 2009 to 2019. All cases were independently reviewed and reclassified following the criteria set out in the latest edition of the World Health Organization 2017 reference text. Demographic and clinico-pathological data were recorded for each case.

RESULTS

Twenty-four cases of malignant odontogenic tumours were identified. The patients' age ranged from 16 to 79 years with the mean age at diagnosis being 50.8 years (SD = 16.18). There was a male predominance (66.7%) in this cohort of patients. The ethnic distribution appeared to reflect the Malaysian population with most cases seen amongst the Malay ethnic group (66.7%). Ameloblastic carcinoma was the most frequently diagnosed malignant odontogenic tumour (45.8%) and was also predominantly seen in males (90.9%). All patients with clear cell odontogenic carcinoma were females. There was no obvious sex predilection in primary odontogenic carcinoma not otherwise specified (NOS). The mandible (79.2%) was more frequently involved compared to the maxilla.

CONCLUSIONS

Diagnosis and management of malignant odontogenic tumours are challenging due to the rarity of these tumours. Our study has elucidated the clinico-pathological features of malignant odontogenic tumours seen in a multi-ethnic Asian population.

Impact of changing classification systems on prevalence and frequency distribution of odontogenic tumors in tertiary care center of Nagpur

INTRODUCTION

The classification of odontogenic tumors has been revised from time to time in order to provide unified terminology. This reclassification had considerable impact on their prevalence and frequency distribution.

OBJECTIVES

This study was aimed to emphasize impact of changing classification systems on prevalence and relative frequency of odontogenic tumors. The secondary objective was to analyze demographics of various histological types of odontogenic tumors in comparison to published literature. Review of Indian studies (1992-2020) elaborating frequency of odontogenic tumors is summarized in the end.

METHODS

This was a hospital-based retrospective study wherein case files of odontogenic tumors diagnosed from 1990 to 2019 period were retrieved. The classification system used originally at the time of diagnosis was retained and prevalence of odontogenic tumors in three different periods (1990-2004, 2005-2016 and 2017-2019) was compared. Further, prevalence, frequency distribution and demographics of all these tumors (1990-2019) were analyzed using latest World Health Organization 2017 classification.

RESULTS

A total of 345 odontogenic tumors was diagnosed as per World Health Organization 2017 system of classification from 1990 to 2019. 96.81% tumors were benign and 3.81% constituted malignant odontogenic tumors. However, there was marked increase in prevalence of odontogenic tumors in 2005-2016 (6.2%) period as compared to 1990-2004 (3.87%) and 2017-2019 (3.47%). Ameloblastoma remained the most common tumor in three different periods, whereas keratocystic odontogenic tumor became second commonest tumor in 2005-2016 as compared to odontoma in 1990-2004 and adenomatoid odontogenic tumor in 2017-2019.

CONCLUSIONS

The continuous evolving systems of classification may partly be responsible for inconsistency in odontogenic tumors, with inclusion of keratocystic odontogenic tumor,and has marked impact on prevalence and frequency distribution of odontogenic tumors. The geographical variations in demographics of odontogenic tumors might reflect genetic and environment influence; however it requires elucidation by further studies.

A Retrospective Study of 158 Cases on the Risk Factors for Recurrence in Ameloblastoma

Background: Ameloblastoma is an odontogenic tumor occurring in jaws, with local aggressiveness and postoperative recurrence. This study was aim to investigate the clinical and radiographic risk factors for recurrence in ameloblastoma. Methods: Patients diagnosed with ameloblastoma between March 2009 and March 2019 were retrospectively analyzed. Clinical and Radiological data and follow-up records were collected. Survival analyses were performed by Kaplan-Meier and log-rank tests, as well as Cox proportional hazards model. Results: One hundred and fifty-eight patients (104 males and 54 females were enrolled. The overall recurrence rate for ameloblastoma was 13.29%, and 10.76% recurred within 5 years. Most of the tumors were located in mandible (86.71%), while the rest 21 cases were in maxilla (13.29%). More than half cases (55.06%) showed multilocular radiolucency, 61 cases (38.61%) showed unilocular radiolucency. Significant differences were found with amelobastoma recurrence rate related to treatment modality, impacted tooth and root resorption (P =0.002, 0.022 and 0.007 respectively). Conclusions: Treatment modality, impacted tooth and root resorption all showed statistically significant associations with the recurrence rate in ameloblastoma. However, due to the limitation of this study, further studies are needed to reveal the true mechanism of ameloblastoma recurrence.

Incidence and Prevalence of Head and Neck Pathological Spectrum in a Pediatric Population

AIM

The aim of this study is to determine the frequency of pediatric pathologies and their distribution according to age, gender, site and types of lesions reported over a period of 2004 - 2019 in two prominent Dental Colleges at Western UP, India.

MATERIAL AND METHODS

All the cases of pediatric pathology were retrospectively analyzed and reviewed that reported in the Department of Oral And Maxillofacial Surgery of 2 prominent dental colleges of Western UP, India. All consecutive patients (< 18 years), between 2004 to 2019, histologically diagnosed as having an intraosseous tumor or tumor-like lesions and cystic lesion, vascular lesions, patients with space infections and hardware infection formed the study population. Patients fulfilling the inclusion criteria were only considered for further study. The study was granted an exemption by the institutes. The entire study material was analyzed and grouped into prominent categories for logical conclusions: The accumulated data was grouped, entered, and analyzed.

RESULTS

One hundred two cases fulfilled the criteria. Gender distribution was equal, with mandible predominance and a predominance of non-odontogenic lesions. There were 4 malignant and 57 benign conditions. There were 23 lesions in the anterior jaw and 38 lesions were present in the posterior jaw.

CONCLUSION

The pattern of pediatric pathology presentation from this part of India has been documented. In this study, the pediatric jaw tumors are less common compared to those in adult jaw tumors with non-odontogenic tumors being more common.

An international collaborative study of 105 new cases of adenomatoid odontogenic tumors

OBJECTIVE

The aim of this study was to report the clinicopathologic features of 105 new cases of adenomatoid odontogenic tumor (AOT) from Brazil, Guatemala, Mexico, and South Africa.

STUDY DESIGN

Clinical and radiographic data were collected from records of 5 oral pathology laboratories, and all cases were microscopically reviewed.

RESULTS

This series of cases included 36 (34.2%) from South Africa; 33 (31.4%) from Brazil; 23 (21.9%) from Mexico; and 13 (12.3%) from Guatemala. Seventy-two patients (68.5%) were females and 33 patients (31.4%) were males, with an average age of 19.2 years. The tumors predominantly affected the anterior maxilla (48.5%), followed by the anterior mandible (29.5%); posterior mandible (15.2%); and posterior maxilla (6.6%). Sixty-three tumors (63.6%) were follicular, 34 (34.3%) were extrafollicular, and 2 (2%) were peripheral. In most cases, the tumors caused considerable cortical expansion (average size 3.4 cm). Microscopically, most cases showed rosette-like and duct-like structures.

CONCLUSIONS

This is one of the largest case series of AOTs reported in the literature and the first multicenter study involving populations from Latin America and South Africa. In a fifth of the present cases, the posterior regions of the gnathic bones were affected and the tumors demonstrated larger sizes compared with cases occurring in other populations.

Odontogenic tumors: A review of 93 cases in the Vidharba region of Maharashtra

Background:

Tumors of the odontogenic origin (OTs) are rare tumors accounting for 1% of all the jaw tumors in the oral cavity. The behavior of these tumors ranges from hamartomatous proliferation to malignant neoplasm.

Aim:

The aim of this study was to determine the epidemiological data, clinical and histopathological picture with variants of the OTs diagnosed at our institute in the Vidarbha region.

Settings and Design:

A retrospective study was carried out with the permission from the institutional authorities. The archival records of the Department of Oral Pathology and Microbiology were reviewed.

Materials and Methods:

A total of 93 cases of OTs were reviewed retrospectively from the archival records of the Department of Oral Pathology and Microbiology from January 2008 to December 2018. Statistical analysis was carried out and the determination of the age, gender, jaw, site, diagnosis, variants and year-wise distribution of odontogenic lesions was taken out using the SPSS software.

Results:

Ninety-three cases of OTs were identified. The most common OT identified was ameloblastoma (n = 37/39.7%) followed by keratocystic OT (n = 8/8.6%), adenomatoid OT (n = 7/7.5%) and odontome (O) (n = 6/6.4%). The tumors were diagnosed in a wide age range from 1^st to 3^rd decennium of life. The mandibular posterior region was the most commonly affected anatomical site with the maxilla and mandible ratio of 1:6.

Conclusion:

OTs were found to be rare in the sample studied. The findings of the study were in concordance to those of Asian and African series. Variations were shown from the series of American reports, and further investigations are needed for this disparity.

Odontogenic Myxoma: Systematic review and bias analysis

BACKGROUND

Odontogenic myxoma (OM) is a rare neoplasm, which originates from odontogenic ectomesenchyme. There is no study in the literature that analyses the best standards for OM diagnosis and how the treatment modalities may influence the recurrence rates.

OBJECTIVE

To evaluate the best standards for odontogenic myxoma (OM) diagnosis and treatment, and how these may influence the recurrence rates.

STUDY DESIGN

Two independent researchers performed a systematic review in many databases. Fifty-two eligible studies were included for qualitative analysis. Bias analysis was conducted according to Oxford Centre for Evidence-Based Medicine.

RESULTS

A total of 1363 OM cases were reported on, and female gender with average age of 27 years is the most common patient profile. Conventional microscopic findings were observed in 93.43% of the reported cases. In 57.49% of the cases, multilocular radiographic appearance was present, followed by unilocular appearance (32.87%). Posterior mandible was the site with the major prevalence, while surgical resection was the most common treatment modality, followed by enucleation. Recurrence rates for both treatment modalities were approximately close (13.04% and 25.0%, respectively).

CONCLUSION

The correct diagnosis of OM relies on the association of clinical, radiographic and microscopic findings. About imaging examinations, panoramic radiography and computed tomography are sufficient for the evaluation of OM. Recurrence rates were closely among the two most used surgery treatments. So according to some clinical-radiological aspects, conservative surgery may be preferred than aggressive surgery modalities.

Calcifying epithelial odontogenic tumors (Pindborg tumor) of maxilla in pediatric patients

The calcifying epithelial odontogenic tumor (CEOT) was first described by Pindborg as a distinct entity in 1955. Odontogenic tumors are derived from epithelial, ectomesenchymal, and/or mesenchymal elements that are or have been a part of the tooth-forming apparatus. Of all the odontogenic tumors, CEOT accounts for 1% of the cases. There is no sex predilection, with a 2:1 predilection for the mandible, mostly in the premolar/molar region. The CEOT typically presents clinically as an intraosseous, expansile, and painless mass that exhibits slow growth. It is often locally invasive. Most often, it is associated with an impacted tooth, is asymptomatic, and requires biopsy for diagnosis. Although most of these cases are primarily intraosseous, an extraosseous tumor is also known to occur, first observed by Pindborg in 1966. The lesions were surgically enucleated, and histopathological examination confirmed CEOT. The purpose of this article is to describe one additional case of both variants of CEOT.

Evaluation of biopsies of oral and maxillofacial lesions: a retrospective study

Objectives

This study aimed to determine the prevalence of odontogenic cysts, tumors, and other lesions among reports in the archives of the Department of Oral and Maxillofacial Surgery at the Faculty of Dentistry affiliated with Kocaeli University collected over a four-year period.

Materials and Methods

In this retrospective study, patient records from the archive of the Department of Oral and Maxillofacial Surgery from 2014 to 2018 were reviewed. Patient demographic information (age and sex) and lesion location were recorded and analyzed.

Results

From a total of 475 files reviewed, odontogenic cyst was confirmed in 340 cases (71.6%), and odontogenic tumor was confirmed in 52 cases (10.9%). Regarding odontogenic cyst type, the most common was radicular cyst (216 cases), followed by dentigerous cyst (77 cases) and odontogenic keratocyst (23 cases). Among odontogenic tumors, the most frequent was odontoma (19 cases), followed by ossifying fibroma (18 cases) and ameloblastoma (9 cases). Giant cell granuloma was also reported in 35 cases.

Conclusion

The distribution pattern of odontogenic cysts and tumors in our retrospective study is relatively similar to that reported in the literature. Complete clinical reports for final diagnosis of these lesions and routine follow-up examinations are very important for treatment.

Association between odontoma size, age and gender: Multivariate analysis of retrospective data

Background

The variety of characteristics related to odontoma research, including an unexplored one such as size, merits a multivariate approach that allows the adequate drawing of inferences with pertinent conclusions. The objective of this study is to establish the possible association between some characteristics related to the odontoma, tumor size among them.

Material and Methods

The sociodemographic characteristics of 60 patients were evaluated. Diagnosis, size, location, type of treatment performed, and prognosis were determined. These data were analyzed descriptively and through multivariate models.

Results

Thirty-four compound and 26 complex odontomas in 32 men and 28 women were observed. The age average of patients was 15.6±11 years. Most of the odontomas presented a size inferior to 10 mm. A statistically significant association was observed between the routine radiographic finding and the absence of dental eruption (p=0.0001). The model of linear regression adjusted between odontoma size and age (β=0.321, p=0.01), as well as the model of logistic regression adjusted between gender (men) and tumor size (OR=12; 1.7 - 93 IC 95%, (p=0.01) were statistically significant.

Conclusions

Statistically significant associations between odontoma size and age, and between the male gender and odontomas smaller than 10 mm were found adjusting by other confounding variables. These results could grant clinicians a greater knowledge of the context of odontoma characteristics, which in turn could favor a better diagnostic and therapeutic decision-making.

Key words:Odontoma, compound odontoma, diagnosis, multivariate analysis.

The presentation of odontogenic keratocysts in the jaws with an emphasis on the tooth-bearing area: a systematic review and meta-analysis

PURPOSE

This study was conducted in order to gain insight in the actual ratio of odontogenic keratocysts occurring in the tooth-bearing area as compared to the posterior region of the jaws in order to come up with reliable data to base upon a rational treatment policy.

METHODS

We searched MEDLINE, Web of Science, Scopus, and Cochrane databases for studies reporting on the location of mandibular and maxillary odontogenic keratocysts. All records were independently assessed and a meta-analysis was performed. Risk difference with a confidence interval of 95% of having the lesion in the posterior region versus the tooth-bearing area was the effect measure. P value for the summary effect of < 0.05 was considered statistically significant.

RESULTS

The 2615 records retrieved were reduced to 34 studies to be qualitatively/quantitatively assessed. The pooled values showed that the difference in the clinical risk of having keratocysts in the posterior region of the mandible and in the tooth-bearing area of the maxilla is 21 and 43%, respectively (P < 0.02 and P < 0.00001).

CONCLUSIONS

A substantial amount of keratocysts occur in the tooth-bearing area of the jaws, requiring attention.

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.

Malignant ameloblastoma: multiple local recurrence and metastasis in the scalp. Case report

Introduction: Ameloblastoma is a neoplasm usually found in the maxilla and mandible with progressive intraosseous growth and a tendency to local recurrence. Malignant or metastatic ameloblastoma is one of its rare variants; a histopathological study is required for diagnosis confirmation. The common sites of dissemination are the lungs and cervical lymph nodes. The treatment is surgical and radiotherapy or chemotherapy are palliative options.Case report: A case of malignant ameloblastoma was reported in a 39-year-old man with metastasis to the scalp and multiple local recurrences. The patient required mandibular osteotomy, multiple local resections, partial maxillary resection, free flap reconstruction, local scalp resection and free flap coverage. Due to a new relapse that could not be treated with a surgical approach, radiotherapy was ordered.Discussion: The site most frequently affected by malignant ameloblastoma due to hematogenous dissemination is the lung. This paper reports the case of a patient with compromised scalp. To date, according to a search conducted, only one case report about this type of metastatic neoplasm has been published.Conclusion: Histopathological diagnosis of ameloblastoma associated with surgical resection of the primary tumor and the metastatic tumor is the only approach that can offer disease-free survival.

Multiple Complex Odontomas of the Mandible: A Rare Case Report and Literature Review

A 53-year-old female appeared with pain in the right mandible ramus, for the past 9 months, after tooth extraction. Clinical and radiological examination using conventional and advanced computerized tomography diagnostic imaging led to a provisional diagnosis of multiple complex odontomas. Complete conservative excision of the lesion was performed. The clinical diagnosis was confirmed histopathologically. Postoperative period was uneventful with no evidence of recurrence. According to an extensive literature review, this report describes the oldest patient ever diagnosed with multiple odontomas in the literature.

Ameloblastic carcinoma: a clinicopathologic analysis of cases seen in a Nigerian Teaching Hospital and review of literature

Introduction

Ameloblastic carcinoma is a rare malignant odontogenic neoplasm that exhibits histological features of ameloblastoma in combination with cytological atypia. It may arise de novo or secondarily through malignant de-differentiation of pre-existing ameloblastoma or odontogenic cyst. Secondary ameloblastic carcinomas often results from repeated surgical intervention, which is a mainstay of odontogenic tumor management in resource limited settings. To date, relatively few cases of ameloblastic carcinomas have been reported and many cases have been misdiagnosed as ameloblastoma. This is due to its wide range of clinicopathological feature which range from indolent to aggressive. It may present as an aggressive ulcerated mass or as a simple cystic lesion; hence, it often challenging to delineate from its benign counterpart, ameloblastoma.

Methods

this study reviewed the clinicopathological data on 157 cases of odontogenic tumors diagnosed over a 10 years period from the pathology archive of the Oral Pathology Unit of Obafemi Awolowo University Teaching Hospital Complex (OAUTHC), Ile-Ife, Nigeria.

Results

of all these cases, we identified that 64.9% were Ameloblastomas, while 8.3% were ameloblastic carcinomas. Primary subtypes of ameloblastic carcinoma constituted 23.08%, while 69.23% of the cases were of the secondary subtype. We also found that the secondary subtype of ameloblastic carcinomas showed a higher mean duration value of 7.7 years. Most lesions were found in posterior mandible and presented with ulceration, perforation and ill-defined borders radiographically.

Conclusion

this study is among the few that have documented higher frequency of secondary ameloblastic carcinoma in the scientific literature.

Odontogenic tumours in Nigeria: A multicentre study of 582 cases and review of the literature

BACKGROUND

The objective of this study was to classify the various types of odontogenic tumours (OTs) using the newly updated 2017 world health organization (WHO) histological typing and to analyze the prevalence of these tumours among Nigerians as well as to compare the results obtained with reports from world-wide studies.

MATERIAL AND METHODS

The records of four major tertiary hospitals in Nigeria were reviewed over a 12-year (2004-2015) period. Lesions diagnosed as odontogenic tumours were classified into four groups according to the 2017 WHO histological typing. Data which consisted of age, sex and site were analyzed using SPSS for Window (version 20.0; SPSS Inc., Chicago, IL) and frequency tables were computed.

RESULTS

A total of 582 OTs were recorded and reviewed, benign OTs were 573 (98.5%) cases and malignant OTs were 9 (1.5%) cases. Of the benign OTs, the epithelial OTs were the commonest (500; 86%) while the benign mixed OTs were the least frequent (21; 3.6%). The mean age was 30±14 years (age range of 3-77years) and the peak age was in the third decade (197; 33.8%) of life. There was slight male gender and strong mandibular site predilection. Ameloblastoma, was the most frequent OT and it accounted for 75.5% of the OTs, followed by adenomatoid odontogenic tumour (8.1%) and odontogenic myxoma (7.2%). Malignant OTs accounted for 1.5% of the OTs.

CONCLUSIONS

OTs show a geographic variation with tendency for prevalence of the epithelial OTs in Africa. Ameloblastoma has a high prevalence among Nigerians and is the most common OTs in Africa. Prevalence of odontoma is relatively low in developing African countries like Nigeria when compared to the prevalence in developed countries.

Clinicopathological analysis of odontogenic tumors over 22 years period: Experience of a single center in northeastern Brazil

Background

Odontogenic tumors (OTs) are uncommon neoplastic lesions of the maxilla and mandible, which present difficult diagnosis and therapeutics. This paper aims to determine the frequency and distribution of OTs, over a period of 22 years, at a public university in Northeastern Brazil.

Material and Methods

We reviewed all cases of OTs from oral pathology laboratory of Federal University of Rio Grande do Norte (UFRN), from 1996 to 2017. The tumors were classified according to the latest (2017) World Health Organization Classification of Tumors. Data on age, gender, anatomic site, symptomatology, radiographic findings and tumor size were analyzed.

Results

In the analyzed period, 247 cases of OTs were diagnosed. Epithelial tumors were more common with 127 cases (51.8%). The most common tumors were ameloblastoma (n = 112 / 45.4%), odontoma (n = 89 / 36.1%) and odontogenic myxoma (n = 17 / 6.9%). Malignant odontogenic tumors were extremely rare in the studied population with only 2 cases (0.8%) of diagnosed carcinomas. These tumors were diagnosed in a wide age range, from 5 to 81 years, being more common in the second and third decades of life. In general, the mandible was the most affected anatomic site (n = 162/66%) and the mandible:maxilla ratio was of 2:1. Ameloblastoma was the tumor with the highest number of symptomatic cases (n = 26) and with the highest mean size (cm) with 4.5cm.

Conclusions

Odontogenic tumors were rare in the sample studied (2.2%), with ameloblastoma and odontoma being the most common tumors. Continuous studies that show the characteristics of these lesions are fundamental, especially after modifications in the international classification.

Key words:Odontogenic tumors, jaw neoplasms, epidemiology, oral pathology.