4NQO carcinogenesis: a model of oral squamous cell carcinoma / Carcinogenesis inducida por 4NQO: un modelo de carcinoma oral de células escamosas

The experimental oral carcinogenesis induced by the chemical 4-nitroquinoline 1-oxide (4NQO) is one of the most frequent in the study of squamous cell carcinoma of the oral cavity (CCEC). The clear advantage is that the model is very similar to the physiological process of malignancy. The model has clear benefits by and is suitable for applications in therapeutic research.

La carcinogénesis oral experimental inducida por el químico 4-nitroquinolina 1-óxido (4NQO) es uno de los métodos más frecuentes en el estudio del carcinoma de células escamosas de la cavidad oral (CCECO). La clara ventaja del modelo radica en el gran parecido al proceso fisiológico de la neoplasia maligna. El modelo tiene beneficios claros y es adecuado para las aplicaciones de la investigación terapéutica.

Association of nucleolar organizing regions and Ki-67 expression with recurrence rate of hair follicle tumor in dogs / Associação das regiões organizadoras de nucléolos e da expressão do Ki-67 com a taxa de recorrência dos tumores de folículo piloso em cães

Mitotic index, nuclear diameter, number of nucleolar organizing regions, and Ki-67 expression, in hair follicle tumors of 82 dogs were evaluated. Tissue specimens were used to prepare sections for histological staining for number of nucleolar organizing region and immunohistochemical staining for Ki-67. Tumors were classified as trichoblastoma (n=32), benign trichoepithelioma (n=30), pilomatricoma (n=7), malignant trichoepithelioma (n=6), infundibular keratinizing acanthoma (n=5), and tricholemmoma (n=2). Head, dorsum, and limbs were the most affected sites. Malignant trichoepithelioma presented significantly higher mitotic index, number of nucleolar organizing regions and Ki-67 expression. Regarding benign neoplasms, trichoblastoma presented significantly higher mitotic index and number of nucleolar organizing regions. Ki-67 expression did not differ among hair follicle benign neoplasms. Recurrence was only observed in two cases, with one benign trichoepithelioma and one malignant trichoepithelioma. In the two cases, nodules have not been removed with clean surgical margin. It was concluded that in benign neoplasms of hair follicles, the number of nucleolar organizing regions and Ki-67 expression were significantly smaller than in malignant neoplasm. Clean surgical margins are suggested to be more responsible to tumor recurrences than the number of nucleolar organizing regions, expression of Ki-67, and the mitotic index.

O objetivo deste trabalho foi avaliar o índice mitótico, o diâmetro nuclear, o número de regiões organizadoras de nucléolos e a expressão do Ki-67 em 82 tumores de folículo piloso de cães, entre 2000 e 2006. Os tumores foram classificados como tricoblastoma (n=32), tricoepitelioma benigno (n=30), tricoepitelioma maligno (n=6), pilomatricoma (n=7), acantoma infundibular ceratinizante (n=5) e tricolemoma (n=2). A cabeça, o dorso e os membros foram os locais mais frequentemente acometidos. O tricoepitelioma maligno apresentou índice mitótico, número de regiões organizadoras de nucléolos e expressão do Ki-67 significativamente maiores quando comparado aos outros tipos de tumores. Dentre as neoplasias benignas, o tricoblastoma apresentou índice mitótico e número de regiões organizadoras de nucléolos significativamente maiores. A expressão do Ki-67 não diferiu entre os tumores benignos de folículo piloso. A recorrência foi observada apenas em dois casos, incluindo um tricoepitelioma benigno e um tricoepitelioma maligno. Em dois casos, os nódulos não foram removidos com margem cirúrgica completa. Desta forma, conclui-se que nas neoplasias benignas de folículo piloso, o número das regiões organizadoras de nucléolo e da expressão de Ki-67 foram significativamente menores que em neoplasias malignas. Além disto, sugere-se que a margem cirúrgica completa está mais associada à recorrência dos tumores que as regiões organizadoras de nucléolo, a expressão de Ki-67 e o índice mitótico.

Retrorectal and presacral tumors a clinicopathologic study

Neoplasms in the retrorectal or presacral area are uncommon. In this work we aimed at studying the cases of retrorectal or presacral tumors admitted to our institute in the last four years by H and E stain, immunostain and electron microscopy with review of the literature. Twenty nine patients are included in this study, having variable lesions comprising 10 congenital, 2 neurogenic, 1 osseous, 4 soft tissue tumors, 5 multiple myeloma and 7 metastatic lesions. Difficult cases were studied by immunostain and / or electron microscopy. Both techniques proved to be highly specific in diagnosing equivocal cases and determining the cell of origin

Aplicación de la microscopía electrónica y de la inmunohistoquímica al estudio de los tumores malignos: una revisión de su importancia diagnóstica / The use of electron microscopy and immunohistochemistry in the diagnosis of malignant tumors: a review of its diagnosis important

Se discuten los resultados del estudio con el microscopio electrónico de transmisión y con imunohistoquímica de una muestra considerable de tumores malignos examinados en el curso de los últimos veinte años. Se dividieron las neoplasias en tumores de células epiteliales, tumores fusocelulares, tumores malignos de células redondas y tumores de naturaleza endocrina. Se destacan los principales hallazgos ultraestructurales y los resultados con inmunohistoquímica que contribuyen a hacer el diagnóstico preciso, señalado la importancia de estos estudios para el diagnóstico, el pronóstico y el tratamiento de los enfermos de cáncer

La microscopia electronica en el diagnóstico de los tumores de la infancia / Electronic microscopy in the diagnosis of tumors in childhood

Se estudian en nuestro laboratorio las biopsias de 14 casos de tumores en niños. Se someten éstas a una doble fijación con glutaraldehído y ácido ósmico y se incluyen en araldita. Se observan los cortes ultrafinos después de recibir contraste con acetato de uranilo y citrato de plomo en un microscopio electrónico Hitachi H-300. Se expresa que los resultados obtenidos, al estudiar la ultraestructura de estos tumores, permite confirmar el diagnóstico histológico en algunos casos y llegar a conclusiones diagnósticas en otros, en los que se plantearon varias alternativas sobre la histogénesis del tumor, así como en los que el diagnóstico no fue posible por microscopia de luz. Se concluye que debe difundirse el uso del microscopio electrónico en el campo de la patología tumoral pediátrica en nuestro medio

Localizacion inmunocitoquimica de la hormona gonadotropina corionica en la placenta humana y en celulas tumorales / Immunocytochemical localization of chorionic gonadotropin hormone in human placentae and tumoral cells

Mediante el uso de los metodos de peroxidasa anti-peroxidasa e inmunofluorescencia aplicada a tejidos desparafinados y tratados con tripsina, se estudiaron inmunocitoquimicamente un grupo de placentas y tumores malignos. Al utilizar anticuerpos anti-GCH, la hormona gonadotropina corionica humana (GCH) fue localizada en celulas del sincitiotrofoblasto de plancetas de diferentes estados de desarrollo, se encontro ademas, que las celulas de Langhan's y del citotrofoblasto fueron negativas a la inmuno-reaccion. La mayoria de los tumores estudiados fueron encontrados positivos al aplicar los metodos mencionados. Se postula que la inmunosupresion selectiva del huesped por tumores y la inmunosupresion selectiva de tejidos maternos por tejidos fetales, podria estar mediada por la hormona gonadotropina corionica

Cell Reactions to Metastatic Tumors in the Regional Lymph Nodes: Light and Electron Microscopic Studies

Cell reactions to metastatic tumors in the regional lymph nodes were studied by light and electron microscope in 20 cases; i.e. reactive hyperplasia (3), tuberculosis (3), metastatic carcinomas from the breast (4), from the stomach (2), from the lung (2), metastatic epidermoid carcinoma (2), metastatic malanoma (2), and reticulum cell sarcoma (2). The lymph node response was usually germinal center predominence type and the pyroninophilic cell response was a similar pattern of nonspecific germinal centers with prominent reactive hyperplasia. In two cases of undifferentiated tumors, one from the breast and another from the lung, large numbers of pyroninophilic cells were found within the tumor tissue. However, the majority of lymphoid cells surrounding tumor cell or tumor masses were pyronin negative lymphocytes. Electron microscopic observations revealed that the cells surrounding tumor cells were mostly medium sized lymphocytes, occasionally blast cells and mature plasma cells. The contact border between the tumor cells and the surrounding cells was mostly tight and smooth, but occasionally loose with irregular processes, and widely separated in the case with plasma cells. Degenerative changes of adjacent cytoplasm of either the tumor cells or the lymphocytes were not frequent, but in some instances focal degeneration of adjacent cytoplasm, particularly on the side of the lymphocytes, was noted.