A clinico‐pathological comparison between mandibular and maxillary ameloblastomas in Sri Lanka

J Oral Pathol Med (2010) 39 : 236–241 Background: The aim of this retrospective study was to analyse the relative prevalence and the clinico‐pathological characteristics of mandibular and maxillary ameloblastomas in Sri Lanka. Methods: Clinico‐pathological features of a total of 286 cases of ameloblastomas were analysed. Results: Out of the 286 cases, 87.8% (251/286) of ameloblastomas occurred in the mandible, while 10.8% (31/286) occurred in the maxilla indicating a ratio of 8:1. In the mandible, 54% (136/251), 40% (100/251) and 6% (15/251) of tumours and in the maxilla, 23% (7/31), 48% (15/31) and 29% (9/31) of tumours were solid/multicystic ameloblastomas (SMA), unicystic ameloblastomas (UA) and desmoplastic ameloblastomas (DA) respectively. No gender predilection was observed in mandibular or maxillary ameloblastomas. Most of the lesions were observed in 2nd to 5th decade of life (mean age 33.2 years). No differences between mandibular and maxillary ameloblastomas were observed with reference to overall cellularity and mitotic activity. Solid/multicystic and UAs showed a predilection to posterior region, while DAs were frequently found in the anterior region of both jaws. Twenty‐one percentage (60/286) of ameloblastomas presented with recurrences, and 94% (34/36) of these recurrences were observed in cases treated conservatively. Conclusion: In conclusion, mandibular ameloblastomas were more prevalent than maxillary ameloblastomas, while no differences were observed in age or gender distribution between the mandibular and maxillary ameloblastomas. However, higher proportion of DAs and UAs was observed in the maxilla compared with some of the other studies. SMA should be treated with resection to prevent recurrences.     

成釉细胞瘤的锥形束CT表现分析

目的 对成釉细胞瘤的锥形束CT（CBCT）表现进行总结分析,为其临床诊断提供依据。方法 对病理确诊的有完整CBCT影像资料的37例成釉细胞瘤病例进行回顾性分析,观察其不同CBCT表现。结果 37例资料中,31例为原发病例,6例为复发病例。CBCT表现： 37例病变中,有 36例（97.3%）为骨内型,其中多房型 17例,单房型 17例,蜂窝型 2例; 1例（2.7%）为骨外型,即软组织型。88.2%（15/17）多房型病变内见舌形嵴;34例（94.4%）颌骨呈唇颊侧或（和）腭舌侧膨隆,颌骨骨密质局部不连续。结论 CBCT检查能精确地反映成釉细胞瘤病变形态和内部结构,对其术前诊断及手术计划具有重要的指导意义。     

Histopathology of ameloblastoma of the jaws; some critical observations based on a 40 years single institution experience

The aim of the present study is to examine all cases of intraosseous benign ameloblastomas treated between 1970 and 2010 in a single institution and to look for a possible correlation between the histopathological aspects and the demographical and clinical parameters, as well as the treatment outcome. The data of a total number of 44 patients were retrieved from the records. Nine patients were excluded because of doubt about the correct diagnosis (8 patients) or because of an extra-osseous presentation (1 patient). No statistically significant differences were found between the histopathological (sub)types of ameloblastomas and the demographical and clinical parameters, nor between the histopathological (sub)types and treatment outcome. Of the 28 patients treated by enucleation, in 17 patients one or more recurrences occurred, with no significant predilection for any histopathological (sub)type, including the unicystic type. There were no significant differences in the recurrence rate after enucleation in patients below and above the age of 20 years either. In six out of 17 patients with a recurrence, the recurrent lesion showed a different histopathological subtype than was encountered in the primary. In two cases a change from solid/multicystic to desmoplastic ameloblastomas was noticed. In conclusion, the current histopathological classification of benign intraosseous ameloblastoma does not seem to have clinical relevance with the possible exception of the luminal unicystic ameloblastoma that has been removed in toto, unfragmented. Since no primary desmoplastic ameloblastomas were encountered in the present study no further comments can be made on this apparently rare entity.     

A survey of tumours of the jawbones in Hong Kong Chinese: 1963-1982

A total of 114 tumours of the jawbones was confirmed in a survey of 204,583 surgical specimens in Chinese in the University Department of Pathology, Hong Kong from 1963-1982. Odontogenic tumours totalled 82 of which 62 per cent were ameloblastomas. Thus, odontogenic tumours, in particular ameloblastomas, are relatively common in Chinese. In the 51 cases of ameloblastoma, the mean age at presentation in females was significantly younger than in males. Pathological analysis of the ameloblastomas showed the following: (1) connection of tumour epithelium with oral mucosal epithelium suggests a better prognosis; (2) basaloid pattern in the tumour may prognostically indicate a more aggressive biological behaviour; (3) neoplastic infiltration of the grossly normal bone surrounding the tumour mass was frequent; (4) ameloblastomas not uncommonly contained cysts lined by innocuous-looking epithelium; (5) a significant proportion of ameloblastomas appeared grossly as thin-walled unilocular cysts. The implications of these findings in the diagnosis and treatment of ameloblastoma are emphasized.     

Argyrophilic nucleolar organizer regions (AgNORs) in ameloblastomas and adenomatoid odontogenic tumours (AOTs)

Twenty-two cases of ameloblastoma and ten cases of adenomatoid odontogenic tumour (AOT) were analyzed comparatively by the AgNOR technique. Ameloblastomas were distributed into three groups according to their clinical behaviour: primary lesions without recurrences (PLWTR), 5 cases; primary lesions with recurrences (PLWR), 4 cases; and recurrences, 13 cases. The cases were also regrouped according to their histological pattern: follicular (9 cases), plexiform (7 cases), acanthomatous (4 cases) and unicystic (2 cases). Considering histological patterns, there was a significant statistical difference only between follicular and plexiform types. There were no significant differences between the group of ameloblastomas and the group of AOTs or between the three groups of ameloblastomas with different clinical behaviour. Our results strongly suggest that the distinct clinical behaviour of ameloblastomas and AOT is not correlated with their cellular proliferation ratio. Thus, the infiltrative ability of the ameloblastomas is probably not related to the cellular proliferation index of these tumours.     

Primary intra-osseous carcinoma involving the maxilla

Primary intra-osseous carcinoma, especially in the maxilla, is a rare sub-type of odontogenic carcinoma. The authors describe a recurrent case with maxillary involvement. In 1981, an intra-osseous maxillary tumour was excised from a 33 year-old male. There were two recurrences (in 1983 and 1984). Extra-osseous sites for the origin of the tumour were excluded. The histopathological appearance of the tumour was that of a primary intra-osseous carcinoma. At the age of 22 years, the patient had an osteosarcoma of the radius and at the age of 31 years, pulmonary tuberculosis. The differential diagnosis of primary intra-osseous carcinoma is discussed.     

Maxillary ameloblastomas: a review of the literature and of a 15-year database.

INTRODUCTION: Cases of maxillary ameloblastomas from 15-year database (1986-2000) collected in the Department of Cranio-Maxillofacial Surgery of the University Hospital of Zurich were evaluated. PATIENTS: Twenty-six patients suffering from ameloblastoma had been collected. Five of them, had a maxillary ameloblastoma, three females and two males. METHODS: A clinical retrospective study was performed. In addition a review of the literature was undertaken and the findings have been compared and contrasted. PATIENTS: The overall incidence of ameloblastoma within the mandible (21) was four times higher than in the maxilla (5). In 69 per cent of the cases (18) it occurred in men, in 31 percent (8) in women. The sex ratio differed with the maxillary ameloblastomas: 40 percent male (2) and 60 per cent female (3). Although slow growing and nearly painless, it can reach a considerable size within the mid-face involving such highly specialized structures as the orbit, skull-base and brain. Wide resections with a safety margin of healthy bone to prevent local recurrence were undertaken. Nevertheless, recurrence was frequent due to invasion of the adjacent bone. CONCLUSION: On the one hand, a recurrence was found after a simple curettage of a 'dental cyst'. On the other hand, extensive bone destruction, involvement of the nasal cavity, the ethmoidal and sphenoidal sinuses, infiltration of the skull-base and distant metastasis were observed. The current treatment of choice is partial maxillectomy with a 10-15 mm safety margin of healthy bone including the alveolar ridge, the hard palate, the mucosa of the maxillary sinus and the lateral nasal wall. For the removal of tumours close to or invading the retromaxillary space the temporal approach gives ample access.     

Malignant transformation of peripheral ameloblastoma

A peripheral (extraosseous) ameloblastoma was excised from the maxillary left tuberosity of an 82-year-old man. It recurred twice over a 5-year period, once as squamous cell carcinoma and again as undifferentiated carcinoma. Analysis of the literature suggests that peripheral ameloblastomas may have the same potential for malignant transformation as intraosseous ameloblastomas.     

890例颌骨成釉细胞瘤临床病理分析

目的:了解颌骨成釉细胞瘤的临床病理现状, 为临床诊疗提供帮助。方法:回顾性分析2003年1月—2014年6月间于我科住院治疗的890例颌骨成釉细胞瘤的临床病理资料,对其性别、年龄、发病部位、病理表现、治疗方法进行分析。结果:890例成釉细胞瘤患者中,平均年龄40.15岁,男女比例1.62:1。下颌骨受累724例(81.35%),上颌骨受累166例(18.65%),左右颌骨发病率基本相同,颌骨任一部位均可发生。病理亚型中,实体型378例,单囊型427例,是成釉细胞瘤最为常见的病理亚型。治疗方面,414例患者接受刮治手术,212例接受开窗手术,264例接受截骨手术。结论:成釉细胞瘤好发于青年,多见于下颌骨;男性发病率较女性高,下颌磨牙及下颌支区为最易受累部位;实体型及单囊型为最常见的病理亚型,刮治术为最常见的治疗方式。     

Clinicopathological evaluation of 164 dental follicles and dentigerous cysts with emphasis on the presence of odontogenic epithelium in the connective tissue. The hypothesis of “focal ameloblastoma”

Objectives: Some ameloblastomas presumably originate from odontogenic epithelium within the connective tissue of dental follicles and dentigerous cysts. Therefore, it would seem reasonable to discuss as whether odontogenic epithelium proliferations, frankly displaying ameloblastomatous features (“focal ameloblastoma”), should be considered as an “early” ameloblastoma. Study Design: Histopathological reports from 164 dental follicles and dentigerous cysts from the Department of Oral and Maxillofacial Surgery/Oral Pathology of the VU Free University medical center in Amsterdam, The Ne-therlands, were reviewed. Histopathological slides from 39 cases reporting the presence of odontogenic epithelium within the connective tissue were re-evaluated in order to assess the possible presence of focal ameloblastomas. Results: Focal ameloblastomas were detected in one dental follicle and in two dentigerous cysts. During a follow-up period of 6, 8 and 22 years, respectively, no clinical signs of (recurrent) ameloblastoma have occurred in these patients. Conclusions: Focal ameloblastoma possibly represents the early stage of ameloblastoma development. Key words:Ameloblastoma, odontogenic epithelium, dentigerous cyst, dental follicle.     

Immunohistochemical detection of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in ameloblastomas

BACKGROUND: To evaluate the roles of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in tumor progression, expression of MMP-1, -2 and -9 and TIMP-1 and -2 was analyzed in ameloblastomas as well as tooth germs. METHODS: Frozen tissue sections of seven tooth germs and 22 ameloblastomas were immunohistochemically examined using anti-MMP-1, -2 and -9 and anti-TIMP-1 and -2 antibodies. RESULTS: MMP-1, -2 and -9 and TIMP-1 and -2 were expressed strongly in mesenchymal components of tooth germs, and stromal cells of ameloblastomas. Immunoreactivity for MMP-9 in stromal cells of ameloblastomas was significantly stronger than in mesenchymal cells of dental follicles and dental papillae. Dental laminae showed weak MMP-2 expression in six tooth germs, MMP-9 expression in two tooth germs and TIMP-1 expression in six tooth germs. Some tumor cells showed weak MMP-2 expression in 19 ameloblastomas, MMP-9 expression in four ameloblastomas and TIMP-1 expression in all cases. TIMP-2 reactivity was prominently found in basement membrane zones of dental laminae in tooth germs, and tumor cell islands or nests in ameloblastomas. CONCLUSION: Expression of MMPs and TIMPs was considered to be associated with interactions between epithelial cells and mesenchymal components in normal and neoplastic odontogenic tissues; these molecules might play a role in regulation of tumor progression in ameloblastomas as well as regulation of developmental processes in tooth germs.     

Metastasis to the lateral retropharyngeal lymph node from squamous cell carcinoma of the oral cavity: Report of three cases

Carcinoma of the oral cavity sometimes metastasizes to the lateral retropharyngeal lymph node (LRPLN), especially when posteriorly invading the soft palate or oropharynx. CT or MRI imaging has enabled detection of LRPLN metastasis in the early stage, but the prognosis of patients with metastasis to this node is extremely poor. The authors report three patients with squamous cell carcinoma of the oral cavity with no posterior invasion who developed metastasis to LRPLN during observation. The primary sites of these three cases were gingiva of the upper incisor region, gingiva of the lower premolar region, and maxillary bone of the upper incisor region. Each patient underwent surgery as their initial therapy, but a recurrent tumor in the LRPLN was detected by CT or MRI despite good loco-regional control. A salvage operation with postoperative radiation therapy was performed for two patients, but only one is still alive with no evidence of tumor 14 months after the last surgery. Management of LRPLN metastasis in oral cancer patients is a challenge for oral surgeons, but early detection by CT or MRI and surgery with postoperative radiation therapy is likely to yield the best local control.     

Dentigerous cyst versus unicystic ameloblastoma – differential diagnosis in routine histology

BACKGROUND: Unicystic ameloblastomas (UAs) and dentigerous cysts (DCs) have an identical clinical and radiographic appearance. Some subtypes of UAs have a better prognosis than solid or multicystic ameloblastomas, and simple enucleation is the adequate treatment. The present study was designed to test the hypothesis that UAs with small islands of ameloblastomatous epithelium may be misdiagnosed as a DC or keratocyst if no more than two histologic sections are examined. METHODS: A total of 101 resection specimens from 22 women and 73 men (mean age: 46.5 years) were selected, all showing the clinical and radiographic features of a DC. Only cysts with a minimum diameter of 15 mm in the panoramic X-ray were considered for the present investigation. The histopathologic diagnosis had been routinely established by examining two sections. For our study, the specimens were investigated by step sections at 50 microm and by staining of 5 microm thin sections with hematoxylin and eosin (H&E) at 1 mm levels. An average of 15 slides were evaluated per case. RESULTS: Microscopic examination of the step sections did not reveal ameloblastomatous epithelium in the cyst lining epithelium of the 101 cases. Thus, every primary diagnosis of a dentigerous cyst was confirmed. In four cases, additional rather large odentogenic cell nests were detected with palisading of basaloid cells, while there was a lack of other signs of ameloblastic differentiation. All lesions were completely resected, and no additional treatment was performed. CONCLUSIONS: Step sectioning of larger DCs may reveal associated odontogenic cell nests in some cases but does not lead to the detection of formerly missed ameloblastic cells. Thus, unicystic ameloblastomas are not misdiagnosed if only two slides are prepared for routine diagnosis of DCs.     

多排螺旋CT三维成像技术在种植牙上颌窦内提升中的应用

目的 探讨三维螺旋CT在评估上颌后牙区牙槽骨高度及指导上颌窦内提升术中的作用。方法 21例病例拍摄全景片测量牙槽嵴高度后,再拍摄三维螺旋CT测量各部位牙槽骨高度、明确上颌窦底形态。所有病例均采用上颌窦内提升术同期植入种植体。结果 全景片及CT测量得出的植区最低高度分别为（0.85±0.11） cm和（0.70±0.10） cm（P＜0.05）,有统计学差异;经CT诊断平坦、斜坡、“w”型窦底形态分别为3、12、6例。术后均未发生并发症,随访观察12~30个月,短期疗效满意。结论 三维螺旋CT可精确测量上颌骨各部位的骨高度,可明显提高种植前对颌骨质量评估的准确率。     

Soft tissue recurrent ameloblastomas also show some malignant features: A clinicopathological study of a 15-year database

Background

To investigate the clinicopathological features of six cases of soft tissue recurrent ameloblastoma and explore the role of increased aggressive biological behavior in the recurrences and treatment of this type of ameloblastomas.

Material and Methods

In this study, we retrospectively reviewed recurrent ameloblastomas during a 15-year period; six cases were diagnosed as soft tissue recurrent ameloblastoma. The clinical, radiographic, cytological and immunohistochemical records of these six cases were investigated and analyzed.

Results

All the six soft tissue recurrent ameloblastomas occurred after radical bone resection, and were located in the adjacent soft tissues around the osteotomy regions. In Case 4, the patient developed pulmonary metastasis, extensive skull-base infiltration and cytological malignancy after multiple recurrences and malignant transformation was diagnosed. In the other five cases, although there were no cytological signs are sufficient to justify an ameloblastoma as malignant, some malignant features were observed. In Case 1, the tumor showed moderate atypical hyperplasia and the Ki-67 staining percentage was 40% positive, which are strongly suggestive of potential malignance. In Case 5, the patient developed a second soft tissue recurrence in the parapharyngeal region and later died of tumor-related complications. All the remaining three patients showed cytology atypia of varying degrees and high expression of PCNA or Ki-67, which confirmed active cell proliferation.

Conclusions

Increased aggressiveness is an important factor of soft tissue recurrence. An intraoperative rapid pathological examination and more radical treatment are suggested for these cases. Key words: Ameloblastoma, soft tissue recurrence, aggressive biological behaviour.     

Recurrent ameloblastoma of the jaws: A follow-up study

Twenty-six cases of recurrent ameloblastoma of the jaws within a 15-year period are presented. They represent 8.9% of all cases of ameloblastoma seen in this period. The highest incidence was found in the third decade of life. There is a higher incidence of recurrences in the mandible (16/26) as compared to the maxilla (6/26). Over 80% of the recurrences presented within five years of primary surgery, emphasising the need for adequate and intensive follow-up during this critical period. Three patients whose lesions were operated on in the mandible showed similar lesions in the maxilla after a period of time. Conservative procedures at primary surgery produced the most recurrences. The cure rate for surgery of maxillary ameloblastoma was comparatively poor. The need for good visibility, adequate access and radical surgery in maxillary ameloblastoma is stressed.     

螺旋 CT 仿真内镜对上颌窦底的测量研究

目的:探讨螺旋CT仿真内镜(virtual endoscopy VE)对评估上颌窦内提升前后窦底形态改变的意义。方法:对15例上颌窦内提升患者术前术后采用64排螺旋CT扫描,三维重建后仿真内镜观察上颌窦底形态改变,测量内提升高度及窦底种植体表面覆盖的软硬组织的厚度。结果:15例上颌后牙缺失患者经过螺旋CT仿真内窥镜术前测量,可以清晰地看到上颌窦内呈现不规则锥形结构,影像类似于真实内镜的图像。上颌窦底形态平坦型:9例(60.0%),V形:4例(26.7%),窦底分隔:2例(13.3%),上颌窦底最低点位置:上颌第二前磨牙与上颌第一磨牙间,种植有效牙槽骨高度:5-8mm,平均6.5mm。模拟手术评估后共植入21枚种植体。术后螺旋CT仿真内镜可以清晰地看到上颌窦底内提升后局部隆起的"帐篷状"改变,21枚种植体提升上颌窦底3±1.5mm,窦底种植体表面覆盖的软硬组织的厚度2.5±0.8mm。结论:螺旋CT仿真内镜是一种无创性、可重复操作的检查手段,不仅可以对骨组织进行三维重建,还可以对软组织进行重建,能多角度、全方位地清晰显示上颌窦内提升前后窦底形态结构的改变,对基层综合性医院上颌窦内提升有着重要的临床价值。     

Odontogenic tumours: 240 cases diagnosed over 31 years at a Brazilian university and a review of international literature

This study describes the epidemiology and clinical presentation of odontogenic tumours (OT) seen at a regional Brazilian oral and maxillofacial pathology service; to assess the quantitative impact of the most recent World Health Organization (WHO) classification of these lesions; and to compare this series with others available in international databases. The study was carried out by retrospectively analysing 240 cases diagnosed from 1978 to 2009, followed by a comprehensive review of the literature. The patients’ mean age was 29 years, with a male to female ratio of 1:1.1. Benign lesions comprised 97.9% of the cases (mostly keratocystic odontogenic tumours (KCOT), odontomas and ameloblastomas) with the remaining tumours depicting a prevalence of less than 5%. Adenomatoid OT were less frequent than in most previous studies, while malignant OT were strikingly numerous. Most OT in children and in the anterior maxilla were odontomas, while maxillary ameloblastomas were rare. Lack of swelling was more frequent in KCOT than in ameloblastomas. The present study confirms the relative impact of KCOT in the epidemiology of OT and identifies more similarities between the present series with reports from the United States and Europe than with African and Asian populations.     

Playing wind instruments as a potential aetiologic cofactor in external cervical resorption: two case reports

AIM: To present two cases of external cervical resorption (ECR) on maxillary incisors, in which the primary aetiologic factor is suggested to be pressure trauma by frequently playing wind instruments. SUMMARY: The exact aetiological spectrum of ECR is still poorly understood. For resorption to occur, a defect in the cementum layer (trigger) is a likely prerequisite. Whilst the mechanism for continuation (stimulus) is still unclear, knowledge of potential predisposing factors is important in assessing patients at risk. Pressure generated by playing wind instruments could present an aetiological factor in ECR because it affects the cervical region of the root surface. The cases that are presented may confirm this hypothesis and the extent of resorption defects is shown by cone-beam computer tomography (CT) and micro-focus CT imaging techniques.     

Human ameloblastomas in vitro: light microscopical and ultrastructural observations

The light microscopical and ultrastructural morphology in vitro of one case each of human plexiform, follicular and acanthomatous ameloblastoma are described. Ultrastructural analysis of cultured tumour cells revealed that the main cell type growing in vitro displayed morphological features typical of columnar cells or preameloblast-like cells of ameloblastomas. Irrespective of histological type all cases showed indistinguishable in vitro light microscopical and ultrastructural morphology. These findings strongly suggest that the columnar cell type accounts for the main proliferative capacity of ameloblastomas in vitro and most likely also in vivo.