Aggressive pregnancy tumor (Pyogenic Granuloma) with extensive alveolar bone loss mimicking a malignant tumor: case report and review of literature / Tumor agresivo del embarazo (Granuloma Piógeno) con gran pérdida del hueso alveolar simulando un tumor maligno: Reporte de caso y revisión bibliográfica

Oral pyogenic granuloma is a hyperplastic inflammatory lesion commonly associated to local irritation or trauma. Females are more affected than men probably due to the vascular effects of hormones that occur during puberty, pregnancy and menopause. In the pregnancy, the lesions are known as "pregnancy tumor" and tend to occur more frequently during the second and third trimester. In the oral cavity, histopathological examination is required for diagnosis, since the lesion is clinically indistinguishable from other reactive lesions and, usually, there is no evidence of bone involvement. The authors report a rare case of pyogenic granuloma with destruction of alveolar bone mimicking a malignant tumor in a 20-year-old woman in the 19th week of pregnancy.

El granuloma piógeno oral es una lesión hiperplásica inflamatoria asociada a la presencia de irritación local o trauma. Las mujeres son más afectadas que los hombres, probablemente debido a los efectos vasculares de las hormonas que se producen durante la pubertad, el embarazo y la menopausia. En el embarazo, las lesiones se conocen como "tumor del embarazo" y tienden a ocurrir con más frecuencia durante el segundo y tercer trimestres. En la cavidad oral, el examen histopatológico es necesario para el diagnóstico, ya que la lesión es clínicamente indistinguible de otras lesiones reactivas y, por lo general, no hay evidencia de afectación ósea. Los autores divulgan un caso raro de granuloma piógeno con la destrucción del hueso alveolar simulando un tumor maligno en una mujer de 20 años de edad, en la semana 19 de embarazo.

Odontogenic myxoma: clinico-pathological, immunohistochemical and ultrastructural findings of a multicentric series.

The aim of this study was to analyze the clinico-pathological and immunohistochemical features of 62 cases of odontogenic myxoma (OM) diagnosed in three Oral Pathology Diagnostic Services in Latin America, as well as to describe the ultrastructural features of three of these cases. OM showed a wide age range (9-71 years), with a mean of 27.97 yr (SD: 11.01) and a male to female ratio of 1:2.2. Mandible was affected in 37 cases (59.6%) and maxilla in 25 (40.4%), with 61.3% located in the posterior region. Thirty-nine cases (62.9%) were multilocular and 23 (37.1%) unilocular. Size ranged from 1 to 13 cm, (mean: 5.2 cm). Thirty-seven multilocular (54.8%) and 6 unilocular lesions (26%) were larger than 4 cm (p<0.05). Epithelial islands were identified in 5 cases (8%) on H&E stained sections, but AE1/AE3 and CK14 disclosed these structures in 15 cases each (24.2%); CK5 was positive in 8 (12.9%); CK7 in 2 (3.2%) and CK19 in only 3 cases (4.8%). All cases were negative for CKs 8 and 18, S-100 protein, NSE and CD68, and showed a low index of expression of Bcl2 and ki-67 proteins (<1%). Mast cell antibodies showed these cells in 45 cases (72.6%). Myofibroblastic differentiation evidenced by myofilaments and fibronexi was found in one case out of the three studied by TEM and 29 cases (46.7%) were positive by immunohistochemistry for alpha actin. In conclusion, only a minority of OM had epithelial islands, and only 3 cases expressed CK 19, indicating an odontogenic epithelium origin. Immunohistochemical and ultrastructural findings suggest that OM is a mesenchymal neoplasm in which several factors may contribute to its pathogenesis, including myofibroblastic differentiation and the participation of mast cell products. However, further investigations are needed to better understand the participation of these elements in this particular neoplasm.

Complex odontoma: confocal laser scanning microscopy analysis of a case.

Confocal laser scanning microscopy (CLSM) represents a recent acquisition in the study of biological samples stained for fluorescence observation. Particularly, this technique allows a bidimensional investigation of tissues and cells with the possibility to elaborate a three-dimensional model. The aim of this study is the use of this technique, as a complementary and not substitutive application of the histological examination, for the morphological and histopathological analysis in a case of mixed complex-composed odontoma. The analyzed specimen has been surgically removed in the superior frontal region in a 12 year-old boy and submitted to conventional histopathological analysis. The specimen, hematoxylin-eosin stained, has been subsequently submitted to confocal laser scanning microscopic analysis in autofluorescence by using a Nikons C1 system. This analysis has underlined not visible aspects in traditional optical microscopy, such as the mineralization of hard tissues and the morpho-structural organization of the cellular component. The presence of enamel and dentin may be observed in the different phases of odontogenesis with clear fluorescence gradients determined by the different mineralization degrees. Thus, the odontogenetic components appear strongly autofluorescent in the classical follicular configuration. Three-dimensional reconstruction is made possible by the acquisition of serial bidimensional images that are subsequently analysed by using a specific software device. This study shows the confocal laser scanning microscopy versatility in the analysis of odontogenic neoplasms with production of mineralized tissues.

Lesiones de células gigantes de los maxilares / Giant-cell lesions of the jaws

Teniendo en cuenta las dificultades diagnósticas que ofrecen las lesiones gigantocelulares de los maxilares, se realiza el presente artículo en el que se recoge una síntesis sobre estas lesiones desde el punto de vista clínico, radiológico e histopatológico. Se presentan fotos que ilustran los aspectos conceptuales debatidos y que constituyen parte de las discrepancias históricamente manejadas en torno a las mismas

Myofibrosarcoma of the upper jawbones: a clinicopathologic and ultrastructural study of two cases.

Two problematic spindle cell sarcomas involving upper jawbones in two adult male patients have been studied by histology, immunohistochemistry, and transmission electron microscopy, and respectively graded as low-grade malignancy and high-grade malignancy. While any single methodological study did not allow confident classification of them into one or other of the classical categories of spindle cell sarcomas (fibrosarcoma versus leiomyosarcoma), the overall contribution from all three methodologies ultimately allowed them to be categorized as sarcomas with myofibroblastic differentiation. Histologically, both tumors had morphological features of an amalgama between neoplastic fibroblasts and smooth muscle cells. Immunohistochemically, both tumors expressed reactivity only for muscle specific actin and alpha smooth muscle actin, in addition to vimentin. Ultrastructurally, both tumors, while showing fibroblast-like cytoplasmic features, had a spurious and imperfectly organized cell surface defying convincing classification into any of specific categories (i.e., both appeared in terms of ultrastructure as poorly differentiated sarcoma, the former with low level of smooth muscle differentiation and possibly the presence of some fibronexus component, the latter with no smooth muscle differentiation but with possible evidence of very rare fibronectin fibril). Therefore, on balance, the most tenable diagnosis seemed to us that of a myofibrosarcoma in both cases. This work is presented considering the fact that myofibrosarcoma currently represents a topical theme of debate, and that this is the first report in medical literature concerning with myofibrosarcomas of the head and neck area in adults.

A novel cell line that retains the morphological characteristics of the cells and matrix of odontogenic myxoma.

Little is known about the histogenesis of the human odontogenic myxoma or the relation between tumour cells and the matrix. In order to attempt to remedy this situation, we established and investigated a cell line derived from a human odontogenic myxoma. To our knowledge this is the first cell line derived from this tumour. The cell line, named Mix 1, preserved features of the tumour cells. Mix 1 cells expressed vimentin, type I collagen, fibronectin, tenascin and hyaluronic acid. Ultrastructural analysis of cells of the tumour and cell line demonstrated similarities, both containing Golgi apparatus, rough endoplasmic reticulum and mitochondria indicative of secretory cells. Ultrastructural analysis showed the matrix to be represented by bundles of collagen fibrils in the tumour, and by irregular filaments in cultures more than 60 days old. The Mix 1 cell line promises to be an excellent model for investigating the biology of the odontogenic myxoma.

A case report of a compound odontoma causing delayed eruption of a central maxillary incisor: clinical and microscopic evaluation.

A case of a compound odontoma caused delayed eruption of a central incisor in the maxilla is presented with clinical, radiographic, and microscopic findings. The odontoma was surgically removed and microscopic examination showed a lot of crown-like structures in a very irregular form, some of which were fused to each other at their apical parts. Enamel and pre-enamel were totally abnormal, whereas the inside of the pulp chamber tissue did not present any histological sign of functional tissue. The most homogeneous tissue was dentin. The removal of the odontoma was followed by a rapid eruption of the impacted central incisor.

Clear cell variant of calcifying epithelial odontogenic tumor (CEOT) in the maxilla: report of a case with immunohistochemical and ultrastructural investigations.

A rare case of clear cell variant of calcifying epithelial odontogenic tumor is presented with immunohistochemical and ultrastructural investigations. A 14-year-old Japanese girl was admitted with a complaint of swelling in the right posterior maxilla. Radiological examination showed a well-circumscribed radiolucent lesion located close to the impacted third molar. After only a partial tumor excision, the tumor recurred 13 years later. It appeared radiologically as an irregular radiodensity, and a subtotal maxillectomy was performed. Histological examination showed sheets and/or strands composed almost entirely of clear vacuolated epithelial cells in a stroma containing intercellular amyloid-like material and calcification. Histochemical and ultrastructural analysis detected cytoplasmic glycogen granules in the clear cells, and positive immunoreactivities for cytokeratins 8, 13 and 19; filaggrin and anti-ameloblastoma antibodies suggested an odontogenic epithelial origin.

Odontogenic ghost cell carcinoma: a case report with immunohistochemical and ultrastructural characterization.

The odontogenic ghost cell tumor (OGCT) is the rare, neoplastic variant of the calcifying odontogenic cyst (COC). To date, there have been only four reports of malignant OGCTs, in five patients. We report an additional case of a malignant odontogenic ghost cell tumor that involved the right maxilla of a 20-year-old man. Our report includes its immunocytochemical and ultrastructural characterization.

Myoepithelial tumors of salivary glands: a clinicopathologic, immunohistochemical, ultrastructural, and flow-cytometric study.

Myoepitheliomas of the salivary glands remain a controversial entity. To contribute to the knowledge of this entity, 16 myoepithelial tumors of the salivary glands were studied: 12 benign myoepitheliomas (BME) and 4 malignant myoepitheliomas (MME). The clinical and the histologic findings of each case were studied Immunohistochemistry and flow-cytometry analysis were performed from the paraffin-embedded material in 15 cases. An electron-microscopy study was performed in 8 cases. The myoepithelial tumors affected patients of both sexes equally. The mean age of the patients with BME was 54 years, and the mean age of patients with MME was 62 years. Eight cases of BME originated in the parotid gland and 4 cases originated in the minor salivary glands. All the MME developed from a benign preexistent tumor: two developed from a pleomorphic adenoma in the parotid gland, and the other two MME developed in the minor salivary gland from a BME. The myoepithelial tumors were composed of epithelioid, plasmacytoid, spindle, or clear cell types, and they showed a solid or a myxoid pattern of growth. Immunohistochemical studies revealed marked and diffuse positivity to cytokeratins, vimentin, and S-100 protein in all cases. Glial fibrillary acidic protein was positive in 8 cases (53%), and muscle-specific actin and smooth-muscle actin were positive in only 3 cases (20%); they were all cases of BME. Desmin was negative in all tumors. Ultrastructural studies showed the presence of basal membrane, tight junctions, intermediate filaments, and microvilli as well as actin-like filaments lacking focal densities in all cases. But actin-like filaments with focal densities were not identified. Flow cytometry determined that all BME were diploid with a mean proliferative index of 7.73%. Two of the MME were diploid and the other two MME were aneuploid. The mean proliferative index of MME was 11.93%. In conclusion, BME and MME originated in major and minor salivary glands can display different histologic patterns and cellular features. Some immunohistochemical and ultrastructural characteristics have been found in all these neoplasms, which supports the idea that myoepitheliomas are composed by neoplastic modified myoepithelial cells, not fully differentiated. These techniques can be useful for the diagnosis of these tumors.

Calcifying epithelial odontogenic tumours in small domesticated carnivores: histological, immunohistochemical and electron microscopical studies.

Histological, immunohistochemical and electron microscopical studies revealed one feline and four canine calcifying epithelial odontogenic tumours in 115 oral tumours over a 10-year period. The tumours consisted of islands and sheets of odontogenic epithelium of varying size within a stroma of fibrous connective tissues. The tumour cells were pleomorphic with variable amounts of eosinophilic cytoplasm and large hyperchromatic, polymorphic nuclei with prominent nucleoli. Clusters of keratinized tumour cells ("shadow cells") were frequently seen within the islands and sheets. The multiple spherules of homogeneous eosinophilic material stained positively with Congo red and Dylon stains and produced an apple green birefringence under polarization microscopy, indicative of amyloid. Mineralized foci were scattered throughout the tumour masses and in the homogeneous spherules. Immunohistochemically, the tumour cells reacted with anti-human keratin antibody, but not with anti-human vimentin or anti-chicken desmin antibodies. The homogeneous spherules did not react with anti-human keratin, anti-human vimentin, anti-chicken desmin, anti-amyloid A, anti-laminin or anti-human collagen (type I, III, IV) antibodies. Ultrastructurally, the cytoplasm of tumour cells was abundant and contained a large number of electron-dense bundles of tonofilaments. The homogeneous spherules consisted of fine filaments measuring about 10-12 nm in diameter.

Melanotic neuroectodermal tumour of infancy: an immunohistochemical and ultrastructural study.

Two cases of melanotic neuro-ectodermal tumour of infancy (MNTI)--a rare neoplasm arising in the first year of life--are reported, with the results of immunohistochemical and ultrastructural examination. The tumours consisted of a biphasic cell population in a fibrous stroma. The small, darkly staining cells comprising the first population stained positively for synaptophysin, showing them to be neuroblasts, and the large epithelioid cells comprising the second cell population stained positively with the antibodies HMB-45 and NKI-Beteb, showing them to be melanocytes. Ultrastructural examination of the second case confirmed the biphasic nature of the tumour cells, with secretory granules and neurofilaments in the neuroblastic population, and melanosomes in the epithelioid population. These results add to the evidence supporting the neural crest origin of MNTI and confirm its formation from two distinct cell lines. Both cases have responded to local excision, with no recurrence more than a year after initial treatment.

Rhabdomyosarcoma of the oral cavity. Report of four cases.

Clinical and pathologic findings of four cases of rhabdomyosarcoma of the oral soft tissues are described that include findings from immunohistochemistry and electron microscopy. Three cases occurred in children under 16 years of age and one in a 22-year-old. Included is a brief discussion on reported gene abnormalities that may contribute to neoplastic development.

[Osseous hemangioma of the upper jaw]. / Hemangioma óseo de maxilar superior.

Osseous hemangioma is a rare tumour of head and neck localisation. In this work the AA. present a case of the tumour located in the upper maxilla, considering the actual concept and the possibilities of differential diagnosis in relation with both radiologic and anatomopathological characteristics.

Maxillary ameloblastoma with intracranial invasion--case report.

A 79-year-old male presented with recurrent maxillary ameloblastoma with intracranial invasion into the left orbit, previously histologically diagnosed as benign ameloblastoma. Skull x-ray films and computed tomography showed the multicystic mass had destroyed the skull base. The tumor was nearly completely removed. However, microscopic examination revealed residual tumor cells around the left optic nerve. Histological examination found no malignant transformation in the tumor specimen. Aggressive complete removal of maxillary ameloblastoma should be attempted even in cases of intracranial invasion.