Ameloblastic carcinoma: Clinicopathological analysis of 18 cases and a systematic review.

OBJECTIVES: Exploring the clinicopathological features of ameloblastic carcinoma (AC) and reviewing the literature to improve the diagnosis and treatment of the disease. MATERIALS AND METHODS: Clinical data and pathological features of 18 cases of AC were retrospectively analyzed. A systematic review was carried out by searching PubMed and Medline databases using the MeSH terms "ameloblastic" and "carcinoma." RESULTS: In the systematic analysis, 125 cases of AC from 81 eligible original studies and 18 cases of AC from this research were included. The male-to-female ratio was 2.58:1, and the mandible-to-maxilla ratio was 1.80:1. Mean age of patients was 45.3 years. Thirty-seven cases of recurrence and 27 cases of metastasis were recorded. CONCLUSION: AC is a rare neoplasm of the odontogenic epithelium. A systematic review indicates that diagnoses at the early phase and a close periodic assessment for recurrence and metastasis are necessary.

Recurrence factors in pediatric ameloblastoma: Clinical features and a new classification system.

BACKGROUND: Ameloblastomas of jaw in the pediatric population are a rare clinical entity and have not been well addressed in the literatures. The present retrospective study analyzed the risk factors associated with recurrence of pediatric ameloblastomas. METHODS: Cases of primary pediatric ameloblastomas seen in a tertiary hospital between 2005 and 2015 were analyzed to identify the clinical factors associated with recurrence. RESULTS: There were a total of 104 cases of primary pediatric ameloblastomas. The overall mean maximum tumor diameter was 4.11 ± 1.339 cm. The receiver operating characteristic curve and the Youden Index showed an optimal cutoff point of 4.95 cm to accurately predict recurrence. Bone cortex/soft tissue invasion were associated with tumor recurrence (P < .001). CONCLUSIONS: The maximum tumor diameter, root resorption, and bone cortex/soft tissue invasion were risk factors for recurrence of pediatric ameloblastomas. The new classification system may serve as a predictor of recurrence in pediatric ameloblastomas.

COX-2 as a determinant of lower disease-free survival for patients affected by ameloblastoma.

Ameloblastoma is a locally aggressive neoplasm with a poorly understood pathogenesis. Therefore, the aim of this study is to investigate whether COX-2 expression is associated with ameloblastoma microvascular density (MVD) and with tumor aggressiveness. Sixty-three cases of primary ameloblastomas arranged in tissue microarray were submitted to immunohistochemistry against cyclooxigenase-2 (COX-2) and CD34. Clinicopathological parameters regarding sex, age, tumour size, tumour duration, tumour location, treatment, recurrences, radiographic features, vestibular/lingual and basal cortical disruption and follow-up data were obtained from patients' medical records and correlated with the proteins expression. The results on BRAF-V600E expression were obtained from our previous study and correlated with COX-2 and CD34 expressions. Log-rank univariate analysis and multivariate Cox regression model were done to investigate the prognostic potential of the molecular markers. Twenty-eight cases (44.4%) exhibited cytoplasmic positivity for COX-2, predominantly in the columnar peripheral cells, with a mean MVD of 2.2 vessels/mm2. COX-2 was significantly associated with recurrences (p < 0.001) and BRAF-V600E expression (p < 0.001), whereas lower MVD was associated with the use of conservative therapy (p = 0.004). Using univariate and multivariate analyses, COX-2 was significantly associated with a lower 5-year disease-free survival (DFS) rate (p < 0.001 and p = 0.012, respectively), but not with a higher MVD (p = 0.68). In conclusion, COX-2 expression in ameloblastomas is not associated with MVD, but it is significantly associated with recurrences and with a lower DFS.

BRAF-V600E expression correlates with ameloblastoma aggressiveness.

AIMS: The aim of this study was to investigate whether the expression of BRAF-V600E determines an aggressive clinical and molecular presentation of ameloblastoma. METHODS AND RESULTS: Ninety-three cases of solid ameloblastomas were arranged in a 1.0-mm tissue microarray (TMA) block. Immunohistochemistry against a large panel of cytokeratins (CK), epidermal growth factor receptor (EGFR), parathyroid hormone-related peptide (PTHrP), syndecan-1, Ki67, p53 and BRAF-V600E were performed. Clinicopathological parameters, including sex, age, tumour size, tumour duration, tumour location, treatment, recurrences, radiographic pattern, vestibular/lingual and basal cortical plates disruption and follow-up data, were obtained from patients' medical records. Immunoexpression of BRAF-V600E was investigated in 73 cases that remained available in TMA sections. Our results indicated that 46.6% (34 cases) demonstrated cytoplasm positivity (six weak and 28 strong positivity). BRAF-V600E expression was associated significantly with the expression of CK8 (P = 0.00077), CK16 (P = 0.05), PTHrP (P = 0.0082) and p53 (P = 0.0087). Additionally, a significant association was seen with the presence of recurrences (P = 0.0008), multilocular radiographic appearance (P = 0.044) and disruption of basal bone cortical (P = 0.05). Univariate analysis showed that BRAF-positive cases (P = 0.001), EGFR-negative/weak positive cases (P = 0.03) and multilocular tumours (P = 0.04) had a significantly lower disease-free survival rate, but these parameters were not considered independent prognostic factors in the multivariate analysis (P > 0.05). CONCLUSIONS: Our findings suggest an association of BRAF-V600E with parameters of a more aggressive behaviour of ameloblastoma, supporting the future use of BRAF inhibitors for targeted therapy of this neoplasm.

Ameloblastoma: 25 Year Experience at a Single Institution.

Ameloblastoma is a rare, locally aggressive odontogenic neoplasm, accounting for fewer than 1 % of head and neck tumors. Recent literature suggests that the initial surgical approach and histologic growth patterns are the most important prognostic determinants in ameloblastoma. The aim of this study was to compare the clinical presentation, management, and outcomes of patients with ameloblastoma with data reported in the literature; the study spanned 2 decades at a single institution. The institution's database was searched for all patients with pathologically confirmed ameloblastoma, diagnosed between 1990 and 2015. The data collected included sex, age, clinical and imaging findings, management, histologic pattern, clearance of surgical margins, length of follow-up, time to recurrence, and disease-related mortality. The potential risk factors of recurrence were evaluated using log-rank test, proportional hazard model, and Fisher exact test. Review of the database yielded 54 patients with pathologically confirmed ameloblastoma and follow-up. Recurrence was noted in 13 (24 %) patients. Surgical approach was associated with the risk of recurrence (6.1 % following radical resection vs. 52 % following limited surgery, p = 0.002). There were trends toward higher recurrence rate in the group with pathologically documented positive margins (p = 0.054) and in follicular ameloblastoma (p = 0.35). Transformation into ameloblastic carcinoma was identified in two patients. There was no disease-related mortality. Our study confirms the recent data regarding the importance of radical surgical resection in management of ameloblastoma. Surgical approach appears to be the strongest predictor of tumor clearance.

Ameloblastic carcinoma: a Brazilian collaborative study of 17 cases.

AIMS: Ameloblastic carcinoma (AMECA) is an odontogenic malignancy that combines the histological features of ameloblastoma and cytological atypia. Because of its rarity, it poses difficulties in diagnosis. The aim of this study was to investigate the socio-demographic data, histopathology, immunohistochemical features, treatment and outcomes of 17 cases. METHODS AND RESULTS: Descriptive statistical analyses were used to portray the clinicopathological data collected, retrospectively. Log-rank tests were performed to determine new prognostic factors. Lesions were immunostained for Ki67, p16, p53, and cytokeratins (CKs), and compared with solid/multicystic ameloblastomas (n = 15). AMECA was mostly diagnosed at a late stage, affecting the posterior mandible of male patients in their fifth decade of life. Recurrence was diagnosed in nearly 90% of treated patients, and metastasis occurred in four patients. The mean number of Ki67-positive cells was 86.4 ± 66 per field. Tumours were focally positive for CK7, CK8, CK14, and CK18, and diffusely positive for CK19, p53, and p16. AMECA showed increased immunoexpression of CK18, CK19, p16, p53 and Ki67 as compared with benign cases. CONCLUSIONS: Our study has contributed to the improved characterization of the epidemiology, prognostic markers, treatment options and outcomes of AMECA. Current criteria must be reviewed to simplify the diagnostic process for these neoplasms.

Incidence and overall survival of malignant ameloblastoma.

BACKGROUND: Malignant ameloblastoma, comprising metastasizing ameloblastoma and ameloblastic carcinoma, represents 1.6-2.2% of all odontogenic tumors. Due to its rare nature, malignant ameloblastoma has only been reported in the literature in small case series or case reports. Using the Surveillance, Epidemiology and End-Results (SEER) database, we have performed a population-based study to determine the incidence rate and the absolute survival of malignant ameloblastoma. METHOD: Using the International Classification of Diseases for Oncology (ICD-O) codes 9310/3 and 9270/3, data from the SEER database were used to calculate the incidence rate and absolute survival rate of population with malignant ameloblastoma. RESULTS: The overall incidence rate of malignant ameloblastoma was 1.79 per 10 million person/year. The incidence rate was higher in males than females and also higher in black versus white population. The median overall survival was 17.6 years from the time of diagnosis and increasing age was associated with a statistically significant poorer survival. CONCLUSIONS: To our best knowledge, we report the largest population-based series of malignant ameloblastoma. The incidence rate was 1.79 per 10 million person/year and the overall survival was 17.6 years.

Giant ameloblastoma mortality; a consequence of ignorance, poverty and fear.

Ameloblastoma is a benign tumour of odontogenic origin. Although locally invasive, delay in treatment can lead to severe disfiguring of the facial region. In this report, we present two cases, a man and a woman, of a large ameloblastoma that presented with the typical radiographic features of variably sized radiolucent loculations. Patients presented initially with relatively small tumours but due to fear of surgery, ignorance and possibly poverty, tumour growth became enormous. The female patient died while awaiting consent for surgery and the male patient died at home due to complications closely associated with fear and growth of tumour. Literatures on mortality of ameloblastoma are reviewed. The need for more public enlightenment on the nature and treatment of facial tumours is highlighted.

Discoidin domain receptors: a promoter of the aggressive behavior of ameloblastomas.

Discoidin domain receptors 1 and 2 (DDR1 and DDR2) are members of the receptor tyrosine kinases, which regulate fundamental cellular processes concerning proliferation, differentiation, adhesion, motility, and apoptosis. The dysregulation of these receptors is linked to a number of human diseases, including fibrotic disorders, atherosclerosis, and cancer. However, there have been no studies that analyzed the expression of these DDRs in ameloblastomas (ABs). In this study, we investigated the expression level and distribution of both DDRs in ABs and determined whether these receptors could predict the prognosis of the disease. Real-time reverse transcription polymerase chain reaction, western blot, and immunohistochemical analyses were performed to detect the DDR mRNA and protein expression levels in normal oral mucosa (NOM) and ABs. The relationship of the DDRs with the clinicopathology and prognosis of ABs was analyzed statistically. The mRNA expression levels of DDR1 and DDR2 were found to be increased by 3.42- and 3.66-fold in ABs versus NOM, respectively. Recurrent ABs displayed higher DDR mRNA expression than did primary ABs (P < 0.05). Using western blot analysis, the DDR proteins were found to be lower in NOM than in ABs (P < 0.05), and primary ABs showed lower expression levels than did recurrent ones (P < 0.05). Immunohistochemically, the DDR protein expressions were markedly higher in ABs than in NOM (P < 0.05), and AB patients with higher DDR protein expression showed higher recurrence (P < 0.05). Multivariate analysis with the Cox proportional hazards model indicated the expression of both DDRs to be an independent prognostic factor of ABs. It was suggested that the up-regulation of DDR expression might play an important role in the tumorigenesis and aggressiveness of ABs. Thus, DDR protein expression may be considered as a good biomarker for indicating the prognosis of ABs.

EGFR, CD10 and proliferation marker Ki67 expression in ameloblastoma: possible role in local recurrence.

BACKGROUND: Ameloblastoma is an odontogenic neoplasm characterized by local invasiveness and tendency towards recurrence. AIMS: Studying the role played by EGFR, CD10 and Ki67 in the recurrence of ameloblastoma. METHODS: This study was carried out on 22 retrospective cases of mandibular ameloblastoma from the period from Jan 2002 to Jan 2008 with follow up period until Jan 2011 (3 to 8 years follow up peroid). Archival materials were obtained from pathology department, Mansoura university. Paraffin sections of tumor tissue from all cases were submitted for routine H&E stains and immunohistochemistry using EGFR, CD10 and Ki67 monoclonal antibodies. Statistical analysis using of clinical data for all patients, tumor type, EGFR, CD10 and Ki67 expression in relation to recurrence were evaluated. RESULTS: Among the 22 cases, 10 cases were males and 12 were females with sex ratio 1:1.2. Age ranged from 34 to 59 years old with a mean age 44.18 year. Five cases showed local recurrence within studied period and proved by biopsy. No statistically significant relation was found between local recurrence and patient age, tumor size, tumor type, EGFR expression. There was a significant relation between CD10 expression as well as Ki67 labelling index and recurrence (P value = 0.003, 0.000 respectively). CONCLUSION: Evaluation of CD10 and Ki67 status together with conventional histological evaluation can help in providing more information about the biologic behavior of the tumor, while EGFR could be a target of an expanding class of anticancer therapies. Since ameloblastomas are EGFR-positive tumors, anti-EGFR agents could be considered to reduce the size of large tumors and to treat unresectable tumors that are in close proximity to vital structures. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here:http://www.diagnosticpathology.diagnomx.eu/vs/1902106905645651.

Ameloblastic carcinoma: an analysis of 6 cases with review of the literature.

OBJECTIVES: The purpose of this study is to report 6 cases of ameloblastic carcinoma and to analyze all published cases regarding demographic features, clinical behavior, treatment, and prognosis. STUDY DESIGN: We reviewed our 6 cases of ameloblastic carcinoma and 98 cases previously reported in the English literature. Available follow-up data from 59 cases was analyzed. RESULTS: In the analysis of our cases, the average age of 6 patients was 61 years and there was a predilection for the maxilla and male. Five cases arose de novo, whereas 1 case was secondary type of ameloblastic carcinoma. Microscopically, our cases showed malignant cytologic features with some histologic features of ameloblastoma. Malignant cytologic features included nuclear pleomorphism, hyperchromatism, and high mitotic activity (33.3%). Necrosis and vascular invasion were also seen in 4 cases and 1 case, respectively. Immunostaining for cytokeratins 5, 14, and 18 was all positive and labeling index of Ki-67 was 13.91%. Two patients (33.3%) had a metastatic lesion in the regional lymph nodes without distant metastasis. In the analysis of the literature, the mean age was 49.2 years with a wide age range (7-91 years). The rate of occurrence was higher in males, and the most common site of occurrence was the mandible. The male-to-female ratio was 1.97:1 and the mandible-to-maxilla ratio was 1.71:1. Most cases (70%) involved the posterior portion of the jaw. The most common symptom was swelling, followed by pain, ulceration, paresthesia, and trismus. The recurrence rate in patients treated with surgical resection was 28.3%, whereas the rate in cases of conservative therapy was 92.3%. There was a significant correlation between treatment modality and recurrence (P = 0.000). Metastatic lesions were detected in 22% of patients during follow-up, and the lung was the most common area of distant metastasis. The 5- and 10-year survival rates were 72.9% and 56.8%, respectively. There was a significant decrease in the 5-year survival rate in patients with metastasis (21.4%; P = 0.0000). CONCLUSION: Metastasis from an ameloblastic carcinoma is significantly correlated with poor prognosis. Therefore, diagnosis at an early stage and close periodic screening for metastasis are necessary to improve patient prognosis.

Tumor cell proliferation and microsatellite alterations in human ameloblastoma.

Ameloblastoma is the most common odontogenic tumor. It can exhibit a variety of histological patterns, a great infiltrative potential and a high recurrence rate. Mutations in microsatellite sequences are a hallmark of neoplastic transformation but little is known about their role in ameloblastoma development. In this study DNA was extracted from laser-microdissected samples of 24 ameloblastomas and was analyzed for the status of 22 microsatellite loci. The occurrence and the pattern of microsatellite alterations, in form of loss or length variation, was evaluated and correlated with the Ki67 labeling index and with other clinicopathologic parameters. The prognostic significance of these alterations was also evaluated. High Ki67 expression was significantly associated with a shorter disease-free survival (p=0.003 by log-rank test). Alterations of at least one of the selected loci was observed in all (100%) the ameloblastomas analyzed with a mean of 4 altered microsatellites for each tumor. The microsatellites most frequently altered were D9S747 and D11S488 (42%). All the other loci analyzed were altered in less than 40% of cases and some of them (D3S1312, D3S1300, IFNA, D9S164, D13S176 and TP53) did not show alterations in any of the ameloblastomas analyzed. No relationship was observed between the occurrence of microsatellite alterations and other parameters, such as patients age and gender, tumor size, localization and histotype. The occurrence of microsatellite alterations was more frequent in tumors displaying a high Ki67 labeling index (p=0.03) and in a univariate analysis was predictor of an increased risk of disease recurrence (p=0.039 by log-rank test). These findings demonstrate that microsatellite alterations are frequent event in ameloblastomas. They also suggest that evaluation of tumor cells proliferative activity and microsatellite alterations may be helpful to stratify ameloblastomas prognostically and to predict the clinical behavior of these tumors.

Ameloblastic carcinoma of the maxilla: case report and review of the literature.

MATERIAL AND METHODS: A case of ameloblastic carcinoma of the maxilla arising in a 90-year-old patient is presented along with a review of 65 other cases of the international literature. RESULTS: The median age was 44 years with a predominance of men (42/66). The maxilla was concerned in almost one third of cases (21/66). Twenty patients died of disease after a median time of 60 months. Fifteen patients died with metastatic spread in the lung, brain, or bones; the others were due to a local recurrence. The specific survival rate was 68.7% at 5 years. CONCLUSION: Ameloblastic carcinoma is a rare entity of odontogenic tumors that exhibits malignant histologic features in the primary site. Specific mortality, estimated at 31.3% at 5 years, was generally due to a metastatic spread.