Modelo experimental de meningoencefalitis tuberculosa

Tesis (Doctorado en Ciencias Quimicobiológicas), Instituto Politécnico Nacional, SEPI, ENCB, 2010, 1 archivo PDF, (62 páginas). tesis.ipn.m

Neuropatología quirúrgica: Parte III. Patología celular básica

La patología literalmente es el estudio del dolor. Para ser precisos, es una disciplina que une a la práctica clínica con la ciencia básica, identificando cambios macroscópicos o microscópicos en las células, tejidos, y órganos enfermos. De manera tradicional, a la patología se le divide en patología básica o general y patología especial o sistémica. Los cuatro aspectos del proceso de la enfermedad en los cuales se enfoca la patología son la causa de la enfermedad, los mecanismos mediante los cuales se desarrolla, la vía mediante la cual ocurren los cambios estructurales o morfológicos y las consecuencias funcionales

Neuropatología quirúrgica: Parte II. El reporte histopatológico

El reporte histopatológico tiene como objetivo principal el de dar a conocer los factores histopatológicos pronósticos en relación a probable conducta biológica y no solamente proporcionar un diagnóstico específico. Sin embargo, existen algunos elementos histológicos que no permiten en ocasiones, la precisión diagnóstica morfológica, por lo tanto el diagnóstico final de una enfermedad neurológica (al igual que otro tejido en estudio) deberá hacerse de manera interdisciplinaria a través del análisis detallado del estudio clínico, radiológico e histopatológico. Para conseguir el más preciso diagnóstico morfológico, es necesario el llenado completo de la solicitud de los datos generales del paciente, cuadro clínico, evolución de la enfermedad y el diagnóstico clínico. Con esto, se podrá realizar una adecuada correlación clinicopatológica, objetivo principal de cualquier especialidad médica

Neuropatología quirúrgica: Parte I. Indicaciones del estudio transoperatorio

Aunque ya se habían presentado sugerencias sobre la importancia del estudio transoperatorio fue hasta 1905 que Louis B. Wilson en la Clínica Mayo popularizó la biopsia transoperatoria usando tinción con azul de metileno. En neurocirugía al cirujano le interesa saber si una neoplasia esta presente y su grado de malignidad y en esa base normar la conducta. Los estudios pueden ser por congelación y la impronta. El patólogo debe tener la información clínica que permita normar su criterio. Se pueden diferenciar lesiones no neoplásicas que simulan gliomas o gliomas que simulan otras neoplasias

Intraventricular Neurilemmoma (Schwannoma): Shall GFAP Immunostaining Be Regarded as a Histogenetical Tag or as a Mere Histomimetical Trait?

Neurilemmomas are benign neoplasms presumedly derived from Schwann cells which rarely originate within the central nervous system. Moreover, their intraventricular location has been seldom noticed with less than 30 cases reported worldwide. Here, we add another case study to the record as well as the fifth one in Latin American population. A 16-year-old boy without significant past clinical data debuted with headache and progressive left eye blindness during six months. Neuroimaging scans showed a bulky, multiloculated, intraventricular tumour emerging from the posterior horn of the left lateral ventricle. Microscopically, the lesion put on view the classical schwannian histology: spindle cells arranged in both compact and loosely textured areas. Verocay bodies were not present but vessel hyalinisation, pericellular reticulin, and senescent atypia were observed. The immunoperoxidase reactions were also consistent with neurilemmal differentiation; however, glial fibrillary acidic protein expression was widespread and unexpectedly seen. Traditionally conceived as “nerve sheath tumours” the dual immunophenotype herein demonstrated points to a different histogenetical pathway other than sheer Schwann cell derivation. As previously advised by some authors, neoplastic transformation from a multipotent stem cell may explain the occasional finding of these tumours in unconventional intracranial compartments

Lipomatous/Extensively Vacuolated Ependymoma with Signet-Ring Cell-Like Appearance: Analysis of a Case with Extensive Literature Review

“Lipomatous” and “extensively vacuolated” are descriptive captions that have been used to portray a curious subset of ependymomas distinctively bearing cells with a large vacuole pushing the nucleus to the periphery and, thus, simulating a signet-ring cell appearance. Here, we would like to report the first ependymoma of this kind in a Latin American institution. A 16-year-old boy experienced cephalea during three months. Magnetic resonance imaging scans showed a left paraventricular tumour which corresponded to anaplastic ependymoma. Intriguingly, it was also composed of cells with single or multiple hollow cytoplasmic vacuoles sometimes giving a signet-ring cell-like configuration. Immunolabeling of these showed membrane positivity for GFAP, PS100, and CD99, while Ki-67 expression was null. Ultrastructural examination of retrieved paraffin-embedded tissue showed the presence of scarce microlumina filled with microvilli but failed to demonstrate any content in such optically empty vacuoles as only scant granulofibrillary debris was observed. A schism prevails at present regarding these unusual morphological variants, being either “lipomatous” or “vacuolated” based mainly on the EMA immunoprofile. This, however, is a misappropriate approaching. Could it be that perhaps we are dealing with the same histopathological entity or it may simply happen that fixation and artefacts cannot allow for their proper identification

Rhabdoid choroid plexus carcinoma: a rare histological type Carcinoma de plexus coroides de tipo rabdoide: un tipo histológico raro

Primary central nervous system atypical teratoid/rhabdoid tumors mostly occur during early childhood and are almost invariably fatal. These tumors show similar histological and radiological features to primitive neuroectodermal tumor, meduloblastoma and choroid plexus carcinoma, but present different biological behaviors. We present the case of an 18 year-old man who presented headache, vomiting and ataxia. CT-scan and MRI revealed a posterior fossa tumor. A gross total resection was performed. An intraoperative study showed papillary-like tumors with large cells and mitotic features. Histological examination showed two different main growth patterns: solid sheets of undifferentiated polygonal cells with papillary features and rhabdoid cells. Immunohistochemically, these rhabdoid cells were positive for vimentin, epithelial membrane antigen, smooth-muscle actin, cytokeratin, S-100 protein, and glial fibrillary acidic protein. Electro-microscopically, the typical rhabdoid cells contained whorled bundles of intermediate filaments in their cytoplasm. A rhabdoid tumor is a clinicalpathological entity and emphasizes the necessity to distinguish this unique tumor from other pediatric central nervous system neoplasms. Cytopathological features, immunohistochemistry and electro-microscopy differential diagnoses are discussed.Los tumores de tipo rabdoide primarios en cualquier sitio son raros y en el sistema nervioso central son extremadamente raros y ocurren principalmente en niños, el tumor teratoide/rabdoide es el tumor más frecuente dentro de este grupo y de evolución clínica fatal. El tumor neuroectodermico primitivo, medulobalstoma y al carcinoma de plexos coroides son tumores generalmente muestran aspectos clínicos radiológicos e histológicos similares, con evolución diferente. Presentamos el caso de un hombre joven de 18 años que inició con cefalea vómitos y ataxia. La imagen de TC muestra tumor en fosa posterior. Se realizó resección total del tumor. En el estudio transoperatorio se observó neoplasia maligna de células grandes con mitosis y que formaba estructuras papilares. Histológicamente se observaron dos patrones diferentes, uno formado por nidos sólidos de células poligonales indiferenciadas con formación de estructuras papilares y el otro con abundantes células grandes de aspecto rabdoide. Por inmunohistoquímica las células de aspecto rabdoide fueron positivas para vimentina, antigeno de membrana epitelial, actina de músculo liso, citoqueratina, y proteína S-100, La PGAF fue focalmente positiva. Se realizó microscopía electrónica de las células rabdoides que mostraban nidos irregulares de filamentos intermedios intracitoplasmicos y lamina basal. El tumor rabdoide cerebral es clínica como histológicamente una rara entidad en la población pediátrica. Se discute el aspecto citopatológicas de inmunohistoquímica y de microscopia electrónica y sus diagnósticos diferenciales

Comparative Proteomic Study Shows the Expression of Hint-1 in Pituitary Adenomas

Pituitary adenomas (PAs) can be unpredictable and aggressive tumors. No reliable markers of their biological behavior have been found. Here, a proteomic analysis was applied to identify proteins in the expression profile between invasive and non-invasive PAs to search for possible biomarkers. A histopathological and immunohistochemical (adenohypophyseal hormones, Ki-67, p53, CD34, VEGF, Flk1 antibodies) analysis was done; a proteomic map was evaluated in 64 out of 128 tumors. There were 107 (84%) invasive and 21 (16%) non-invasive PAs; 80.5% belonged to III and IV grades of the Hardy–Vezina classification. Invasive PAs (n = 56) showed 105 ± 43 spots; 86 ± 32 spots in non-invasive PAs (n = 8) were observed. The 13 most prominent spots were selected and 11 proteins related to neoplastic process in different types of tumors were identified. Hint1 (Histidine triad nucleotide-binding protein 1) high expression in invasive PA was found (11.8 ± 1.4, p = 0.005), especially at high index (>10; p = 0.0002). High Hint1 expression was found in invasive VEGF positive PA (13.8 ± 2.3, p = 0.005) and in Flk1 positive PA (14.04 ± 2.28, p = 0.006). Hint1 is related to human tumorigenesis by its interaction with signaling pathways and transcription factors. It could be related to invasive behavior in PAs. This is the first report on Hint expression in PAs. More analysis is needed to find out the possible role of Hint in these tumors