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Odontogenic tumors: a study of 340 cases in a Brazilian population.

BACKGROUND: The aim of this study was to determinate the relative frequency of odontogenic tumors (OTs) in a Brazilian population and to compare this data with previous reports. METHODS: We reviewed the achieves of 19 123 specimens from oral pathology laboratory of Universidade Federal de Minas Gerais, from 1954 to 2004. Using the criteria of histologic typification published by the World Health Organization in 1992, we classified the OTs. RESULTS: A total of 340 OTs were found. The frequency of OTs comprises 1.78% of all pathologic specimens in our laboratory. The most frequent tumor was ameloblastoma (45.2%), followed by odontomas (24.91%), and myxomas (9.1%). CONCLUSIONS: Odontogenic tumors are uncommon lesions in this Brazilian population and malignant OTs are very rare. The relative frequency of various types of OTs, age, and gender distribution are similar to those reported in African, Asian but not to Chilean and North American series.

Adolescent↗

Ameloblastic fibroma and related lesions: a clinicopathologic study with reference to their nature and interrelationship.

BACKGROUND: Ameloblastic fibroma (AF) and related lesions constitute a group of lesions, which range in biologic behavior from true neoplasms to hamartomas. The aim of this study was to elucidate the nature and interrelationship of this group of lesions. METHODS: Clinical and pathological studies were undertaken retrospectively on 13 cases of AF and seven cases of ameloblastic fibro-odontoma (AFO). Thirty-three complex odontomas and 33 compound odontomas were also included for comparative purpose. Relevant follow-up data were recorded and the literature was reviewed. RESULTS: The majority of patients with AF (nine cases, 69.2%) were over the age of 22 years with frequent involvement (76.9%) of the posterior mandible. Tumors recurred in four of 11 patients with follow-up information and two recurrent tumors showed malignant transformation. There was no case in this series that could be designated as the so-called ameloblastic fibrodentinoma, apart from one recurrent AF in which further maturation to form only tubular dentin materials was identified. AFO tended to occur at a younger age group with an average of 9.6 years. Recurrence was noted in two of five patients with follow-up data and both recurrent lesions showed limited growth potential and further maturation into a complex odontoma. Significant differences were noted in the age and site distribution between the complex and the compound odontomas. CONCLUSION: Whilst the majority, if not all, of AFs are true neoplasms with a potential to recur and/or of malignant transformation, some, especially those occurred during childhood, could represent the primitive stage of a developing odontoma. Our data also suggests that some AFOs are hamartomatous in nature, representing a stage preceding the complex odontoma.

Adolescent↗

Clinical update--the teeth and the maxillary sinus: the mutual impact of clinical procedures, disease conditions and their treatment implications. Part 2. Odontogenic sinus disease and elective clinical procedures involving the maxillary antrum: diagnosis and management.

Although odontogenic sinusitis is a rare entity when compared to sinus disease of rhinogenic origin, it is extremely important to identify a dental aetiology when it occurs. The offending tooth or teeth would thus require endodontic treatment or extraction, and the sinus disease carefully assessed and appropriately managed. Aetiology and presentation of oro-antral fistulae are also discussed and guidelines for the management of this complication are recommended. Certain lesions such as cysts and tumours may involve the jaws and hence the maxillary antrum; some of these, such as a radicular cyst are quite common, but the rarer ones are included for completeness. Surgical techniques are continuously evolving to optimise form and function of the jaws, and when applied to the maxilla there may be some impact on nasal and sinus function. The advent, and now proven success, of osseointegrated jaw implants have brought with them innovations and refinements of bone grafting techniques, and more recently distraction osteogenesis for augmentation. Maxillary osteotomies for surgical orthodontics, and to facilitate prosthodontic treatment are briefly mentioned, as most of these inevitably involve the antrum and/or nose. This paper discusses, in summary form, important aspects of clinical dental practice which may involve the maxillary antrum. It is thus a broad overview of certain pathologic conditions and elective surgical procedures which have relevance to both medical and dental practitioners.

Bone Transplantation↗

Kinetically-based multiple drug treatment for advanced head and neck cancer.

A multiple drug regimen was given to 36 patients with advanced carcinomas of the head and neck. In 19 of the 24 patients who were assessable the tumour regressed more than 50%; in one it regressed by 25%; and in four it did not respond at all. Multiple drug chemotherapy should be given much earlier in the course of these cancers, preferably as an adjuvant to surgery or radiotherapy.

Antineoplastic Agents↗

Nestin expression in odontoblasts and odontogenic ectomesenchymal tissue of odontogenic tumours.

BACKGROUND: Nestin, one of the intermediate filaments constituting the cytoskeleton, is a marker of neural stem cells or progenitor cells. Its expression is also related to tooth development and repair of dentine. AIMS: The aim of this study was to investigate nestin expression in various odontogenic tumours and evaluate its usefulness for histopathological diagnosis. METHODS: We studied formalin fixed, paraffin embedded specimens from 129 cases of odontogenic tumours and 9 of mandibular intraosseous myxoma. After characterisation of odontogenic ectomesenchymal tissues in these tumours using antibodies to vimentin, desmin, neurofilament, and glial fibrillary acidic protein, we immunohistochemically examined nestin expression. RESULTS: No differentiation towards muscle and nervous tissues was found in the odontogenic ectomesenchymal tissues. Although almost all the ameloblastomas and malignant ameloblastomas were negative for nestin, odontogenic ectomesenchyme in the odontogenic mixed tumours demonstrated nestin immunolocalisation, particularly in the region adjacent to the odontogenic epithelium. Odontoblasts and their processes, pulp cells near the positive odontoblasts, and flat cells adhering to the dentine showed immunoreaction with nestin in the odontomas and odontoma-like component in the ameloblastic fibro-odontomas. Neoplastic cells in almost half cases of jaw myxoma and one case of odontogenic fibroma expressed nestin. CONCLUSIONS: The distribution of nestin in the odontogenic mixed tumours suggests that nestin expression in the odontogenic ectomesenchyme is upregulated by stimulation from odontogenic epithelium. In addition, nestin may also be involved in the differentiation from pulp cells to odontoblasts in odontogenic tumours. Therefore, nestin is a useful marker for the odontogenic ectomesenchyme and odontoblasts in odontogenic tumours. Nestin, one of the intermediate filaments constituting the cytoskeleton, is a marker of neural stem cells or progenitor cells. Its expression is also related to tooth development and repair of dentine.

Adolescent↗

Ameloblastoma in the maxillomandibular region: MR imaging.

Nine patients suspected of having primary ameloblastoma of the mandible or maxilla and five patients with clinical and/or radiologic indications of postoperative recurrence of ameloblastoma were examined with magnetic resonance (MR) imaging. In the former, results were compared with those of conventional radiography, computed tomography (CT), and pathologic analysis. Seven tumors were multilocular; two were unilocular. MR imaging showed a mixed pattern of solid and cystic components (n = 9), irregularly thick walls (n = 9), and papillary projections (n = 6). MR imaging was superior to conventional radiography and CT in demonstrating these findings. However, shell-like bulgings of the bone cortex were demonstrated more effectively with conventional radiography and/or CT in six cases, and soft-tissue invasion was overestimated with MR imaging in four cases. All tumors except one showed strong enhancement of solid components including papillary projections, walls, and septa at enhanced MR imaging. In the latter group of patients, MR imaging correctly demonstrated recurrence in two and no recurrence in three.

Adolescent↗

Role of fine needle aspiration cytology in the preoperative presumptive diagnosis of ameloblastoma.

OBJECTIVE: To determine the role of fine needle aspiration cytology (FNAC) on the preoperative presumptive diagnosis of ameloblastoma. STUDY DESIGN: Sixty-three patients, diagnosed preoperatively and postoperatively with ameloblastoma, were evaluated between 1990 and 2003. The patients were classified according to whether they were diagnosed with ameloblastoma preoperatively or postoperatively, on histologic examination. RESULTS: The accuracy rate for ameloblastoma was 0.95% for all biopsy methods, while the incisional biopsy rate was 75.00%. Concerning clinical diagnosis, ameloblastoma was mistaken mostly (56.41%) for odontogenic cysts (22 of 39). CONCLUSION: FNAC should be utilized more commonly on intraosseous and soft tissue lesions in the oral and maxillofacial regions, to obtain sufficient material. It is convenient, inexpensive and noninvasive as compared with other biopsy methods.

Adult↗

Transforming growth factor beta 2 in epithelial differentiation of developing teeth and odontogenic tumors.

Dysregulation of TGF beta 2, a modulator of cell growth and differentiation, can result in uncontrolled growth and tumor formation. Our comparative studies on the expression of TGF beta 2 mRNA and protein indicate that TGF beta 2 may primarily be a regulator of epithelial differentiation during tooth development (between 13 and 20 gestational wk) and tumorigenesis of odontogenic neoplasms. A paracrine mode of action for TGF beta 2 in early human tooth germ (cap/early bell stage) is suggested by location of mRNA in the mesenchyme surrounding the tooth germ, whereas protein is found in the epithelial dental lamina and enamel organ. During the late bell stage, TGF beta 2 gene expression shifted from the mesenchyme to the odontogenic epithelium and was colocalized with protein, suggesting an autocrine role for the terminal differentiation of ameloblasts. In odontogenic tumors of epithelial origin (ameloblastomas) and epithelial-ectomesencymal origin (ameloblastic fibromas), TGF beta 2 mRNA was mostly located in the mesenchymal tumor component and protein in the epithelial tumor component. Odontogenic ectomesenchymal tumors (myxomas) were not associated with TGF beta 2 mRNA and protein expression. The results imply that TGF beta 2 may play an important role in epithelial-mesenchymal interactions in human tooth morphogenesis and development of odontogenic tumors.

Adolescent↗

Osteogenic and chondrogenic sarcomas of the jaws.

Osteosarcomas and chondrosarcomas are the most common malignancies of the jaw bones, in which the incidence is approximately, 10% of their total distribution. The mandible is the bone of predilection for osteogenic sarcoma, the maxilla for chondrosarcoma. Both sarcomas are preponderantly locally invasive lesions that resist control, with 5-year cure rates less than 50% for either sarcoma.

Chondrosarcoma↗

AIDS-related plasmablastic lymphomas of the oral cavity and jaws: a diagnostic dilemma.

Acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphomas are highly pleomorphic in their clinical, pathological, and biological features. Recent investigations have led to the identification of a particular type of AIDS-related non-Hodgkin's lymphomas presenting in the oral cavity and jaws. This novel category of AIDS-related non-Hodgkin's lymphomas derives from B-cells and has been defined as plasmablastic lymphoma on the basis of its morphological and immunophenotypic features. Clinically, AIDS-related plasmablastic lymphoma is generally limited to the oral cavity at the time of diagnosis, although extension to distant sites frequently occurs at a later stage. Histologically, AIDS-related plasmablastic lymphoma is composed of a monomorphic and cohesive pattern of plasmablasts with basophilic cytoplasm. Phenotypically, AIDS-related plasmablastic lymphoma fails to express the most common B-cell-associated surface antigens, whereas it consistently expresses high levels of plasma cell-associated markers, including VS38c and CD138/syndecan-1. For the purpose of differential diagnosis, the morphological and immunophenotypic peculiarities of AIDS-related plasmablastic lymphoma clearly distinguish these lymphomas from other categories of AIDS-related non-Hodgkin's lymphomas, as well as from undifferentiated large cell carcinomas.

Antibodies, Neoplasm↗