Pedro Roldan

Multimodal navigation in the functional microsurgical resection of intrinsic brain tumors located in eloquent motor areas: role of tractography

OBJECT Nowadays the role of microsurgical management of intrinsic brain tumors is to maximize the volumetric resection of the tumoral tissue, minimizing the postoperative morbidity. The purpose of this paper was to study the benefits of an original protocol developed for the microsurgical treatment of tumors located in eloquent motor areas where the navigation and electrical stimulation of motor subcortical pathways have been implemented. METHODS A total of 17 patients who underwent resection of cortical or subcortical tumors in motor areas have been included in the series. The preoperative planning for multimodal navigation was done by integrating anatomical studies, motor functional MR (fMR) imaging, and subcortical pathway volumes generated by diffusion tensor (DT) imaging. Intraoperative neuromonitoring included motor mapping by direct cortical stimulation (CS) and subcortical stimulation (sCS), and localization of the central sulcus by using cortical multipolar electrodes and the N20 wave inversion technique. The location of all cortically and subcortically stimulated points with positive motor response was stored in the navigator and correlated with the cortical and subcortical motor functional structures defined preoperatively. RESULTS The mean tumoral volumetric resection was 89.1 +/- 14.2% of the preoperative volume, with a total resection (> or = 100%) in 8 patients. Preoperatively a total of 58.8% of the patients had some kind of motor neurological deficit, increasing 24 hours after surgery to 70.6% and decreasing to 47.1% at 1 month later. There was a great correlation between anatomical and functional data, both cortically and subcortically. A total of 52 cortical points submitted to CS had positive motor response, with a positive correlation of 83.7%. Also, a total of 55 subcortical points had positive motor response; in these cases the mean distance from the stimulated point to the subcortical tract was 7.3 +/- 3.1 mm. CONCLUSIONS The integration of anatomical and functional studies allows a safe functional resection of the brain tumors located in eloquent areas. Multimodal navigation allows integration and correlation among preoperative and intraoperative anatomical and functional data. Cortical motor functional areas are anatomically and functionally located preoperatively thanks to MR and fMR imaging and subcortical motor pathways with DT imaging and tractography. Intraoperative confirmation is done with CS and N20 inversion wave for cortical structures and with sCS for subcortical pathways. With this protocol the authors achieved a good volumetric resection in cortical and subcortical tumors located in eloquent motor areas, with an increase in the incidence of neurological deficits in the immediate postoperative period that significantly decreased 1 month later. Ongoing studies must define the safe limits for functional resection, taking into account the intraoperative brain shift. Finally, it must be demonstrated whether this protocol has any long-term benefit for patients by prolonging the disease-free interval, the time to recurrence, or the survival time.

Association of loss of 1p and alterations of chromosome 14 in meningioma progression

Meningiomas are usually benign tumors; however, they can recur after surgical resection and occasionally show histologic progression to a higher grade II and III malignancy. The second most frequently reported genetic abnormality after 22q loss is deletion of 1p, although alterations in 9q, 10q, and 14q are also implicated in meningioma progression. Fourteen tumors comprising six benign, four atypical, and four malignant meningiomas were examined by means of cytogenetic and fluorescence in situ hybridization analysis. All tumors showed losses in different regions of 1p, with 1p11, 1p13, 1p21, 1p22, 1p32, and 1q21 breakpoints; eight tumors also presented alterations of chromosome 14. Five of the six cases with deletions on 1p and normal chromosome 14 were grade I, and two were recurrent. All but one of the eight cases with simultaneous 1p deletion and alterations of chromosome 14 were grade II (3 cases) and grade III (4 cases); all the grade III cases were recurrent. These results support the possible association between changes in 1p and chromosome 14 with the evolution of aggressive meningiomas through tumor progression.

Primary glioblastomas with and without EGFR amplification: Relationship to genetic alterations and clinicopathological features

Glioblastomas express a notable heterogeneity in both the histological and cell patterns with glial astrocytic differentiation. Primary glioblastoma, which is the most frequent presentation (90–95%), occurs mainly in older patients and arises de novo, without any clinical or histological evidence of a less malignant precursor lesion. EGFR amplification has been identified as a genetic hallmark of primary glioblastomas and occurs in 40–60% of cases. However, there exist primary glioblastomas without EGFR amplification/overexpression. The purpose of this study was to stabilize the association between cases with and without EGFR gene amplification with clinical and genetic parameters in 45 cases of primary glioblastomas. EGFR amplification was observed in 24 cases (53%), while in the remaining 21 cases (47%) this alteration was not displayed. And whereas EGFR was overexpressed in 79% of cases with EGFR amplification, only 33% of the cases without EGFR amplification showed overexpression. The amplification of EGFR was associated with amplifications in MDM2 and CDK4 and a higher percentage of cases with promoter methylation of INK4a. Only one case of glioblastoma with EGFR amplification presented TP53 mutation simultaneously. Seven remaining cases with TP53 mutations were glioblastomas without EGFR amplification. The INK4a, INK4b and ARF deletions were similar in the two groups. Primary glioblastomas with and without EGFR amplification did not show any significant differences in average survival. The genetic studies suggest the existence of molecular subtypes within primary glioblastoma that may, when fully defined, contribute toward the development of drugs that specifically target tumors with divergent genetic profiles.

Solitary fibrous tumor of the orbit: Morphological, cytogenetic and molecular features

Solitary fibrous tumor (SFT), a benign neoplasm arising in mesenchymal structures, was initially described in the pleura but subsequently has also been documented in other locations. It is uncommon in the orbit, where it closely resembles other benign spindle‐shaped mesenchymal tumors of this area such as schwannoma, meningioma or hemangiopericytoma. We present a case of orbital SFT in a 34‐year‐old woman. The radiological study showed the presence of an enhanced uptake lesion measuring 2 cm in major diameter. The histopathological evaluation revealed alternating cellular and hypocellular areas with spindle‐shaped cells. The cellular organization displayed a broad variety of irregular morphological patterns. The neoplastic cells were intensely positive for CD34 and vimentin, while S100, epithelial membrane antigen (EMA), Caldesmon, Calretinin and WT‐1 proved negative. The pericellular matrix exhibited strong positivity for CD44 and collagen IV. Scarce mitotic figures, a Ki‐67 nuclear labeling index of <5%, and focal expression of p53 were also observed. Measurement of DNA content revealed a DNA index of 1, indicating a diploid peak in 95% of the tumor cells. A normal 46,XX karyotype was present. No TP53 (exons 5–8) mutations or MDM2 and CDK4 amplifications were observed. No p14ARF, p15INK4B and p16INK4A deletions or hypermethylation were observed in this benign tumor. Following surgical resection and radiotherapy, the patient showed no tumor relapse after one year of follow‐up.

The activation of ERK1/2 MAP kinases in glioblastoma pathobiology and its relationship with EGFR amplification.

The ERK1/2 activated protein kinase (MAPK) pathway is a critical signaling system that mediates ligand‐stimulated signals for the induction of cell proliferation, differentiation and survival, involved in malignant transformation. The purpose of this study was to determine the activation of ERK1/2 in this tumor, and to determine the relationship of ERK1/2 activation with the amplification/overexpression of EGFR as well as with 9p21 locus gene alterations, both of which are genetic factors frequently associated with glioblastoma. We used immunohistochemistry and Western blot analysis to analyze the activation of ERK1/2 in 22 patients with glioblastoma, and we studied the amplification/overexpression of EGFR; as well as the molecular alterations in 9p21 locus genes. Positive immunostaining ERK1/2 was observed in 86.4% of the tumors, displaying mainly nuclear immunolocalization; and by immunoblotting, ERK1/2 was activated in 68% of the cases. The 70% of cases with EGFR amplification presented activated ERK1/2. The joint presence of amplified EGFR and alterations in the 9p21 genes was observed in 50% of the cases, whereas the simultaneous occurrence of these two phenomena with the activation of ERK1/2 was observed in 40% of the cases. Our results suggest that the activation of ERK1/2 is implicated in the pathobiology of glioblastoma. This activation of ERK1/2 is probably related in part to the amplification of EGFR as well as to alterations in 9p21 locus genes (homozygous deletion and promoter methylation). However, the activation of ERK1/2 also involves pathways that are independent of the EGFR.

Meningioma: Un modelo de evolución citogenética en la iniciación y progresión tumoral

Resumen Los meningiomas son tumores del sistema nervioso central con amplia heterogeneidad morfologica. Aunque son generalmente benignos, tienen la capacidad de evolucionar a un grado histologico mayor (atipico y anaplasico) que esta relacionado con un incremento de su agresividad biologica y/o la capacidad de recidivar. Esta evolucion se caracteriza a nivel citogenetico por la monosomia total o parcial del cromosoma 22 en la etapa mas temprana, seguida de cambios cromosomicos secundarios tanto numericos como estructurales durante la progresion tumoral. En este trabajo presentamos una revision sobre 85 casos de meningiomas, 43 benignos, 28 atipicos y 14 malignos, estudiando sus caracteristicas clinicas, histopatologicas y citogeneticas, obteniendose que la introduccion de anomalias numericas como la monosomia 10, 14 y 18, y anomalias estructurales como deleciones del cromosoma lp estan directamente relacionadas con los tumores de mayor agresividad, y especialmente, la combinacion de alteraciones en el cromosoma lp y 14 se presenta con mayor frecuencia en los meningiomas atipicos y anaplasicos. Estos hechos significan que la presencia de cariotipos complejos aumenta progresivamente desde los meningiomas de grado I a los meningiomas de grado III. Asi mismo, estos cariotipos son los mas habituales en los tumores recidivantes.

Hipofisitis granulomatosa idiopática. Estudio morfológico e inmunohistoquímico de una observación

Resumen Los procesos inflamatorios de la glandula hipofisaria constituyen un grupo de interes por su escasa frecuencia. Con frecuencia se presentan como lesiones ocupantes de espacio y cursan con cuadros de panhipopituitarismo. Ello platea problemas de diagnostico diferencial con implicaciones terapeuticas importantes En este trabajo presentamos un caso de hipofisitis granulomatosa idiopatica, en una paciente de 55 anos con crisis diarias de cefalea y panhipopituitarismo y un aumento de tamano de la glandula hipofisaria. La morfologia destaca una lesion inflamatoria granulomatosa no necrotizante, con celulas multinu-cleadas gigantes y un infiltrado linfoplasmocitario. El estudio inmunohistoquimico muestra la presencia de macrofagos (CD68+) y un infiltrado inflamatorio heterogeneo (CD45RO y CD20+). Se analiza el diagnostico diferencial con otros procesos granulomatosos infecciosos o no infecciosos y con la histiocitosis. En la discusion examinamos la posible relacion con la hipofisitis linfocitaria.

Oligoastrocitoma con diferenciación en células en anillo de sello: Estudio morfológico, ultraestructural e inmunohistoquímico

Resumen Presentamos un caso de tumor glial mixto (oligoastrocitoma) con celulas en anillo de sello. Esta diferenciacion celular es rara en tumores gliales del sistema nervioso central. En este estudio analizamos las caracteristicas morfologicas, ultraestructurales e inmunohistoquimicas del tumor. Las celulas neoplasicas con caracteristicas morfologicas en anillo de sello mostraban expresion de GFAP, S-100 y vimentina. En la discusion consideramos el diagnostico diferencial con otros tumores primarios del sistema nervioso central, asi como con metastasis cerebrales de neoplasias con diferenciacion en celulas en anillo de sello.

Monosomía 1p y fosfatasa alcalina en meningiomas. Estudio clinicopatológico, histoquímico y genético en 10 tumores

Fundamento Los estudios citogeneticos en meningiomas indican que la monosomia 1p es unimportante factor en su progresion. En este cromosoma, en 1p34-p36.1, aparecen localizadoslos genes que codifican la fosfatasa alcalina inespecifica (FA-in), enzima de amplia distribucionen el organismo, que se localiza tambien en los meningiomas. La perdida de expresion deesta enzima en los meningiomas ha sido asociada con la monosomia 1p en estas neoplasias. Pacientes y metodo En este trabajo estudiamos 10 meningiomas correspondientes a 8 pacientesque tienen como caracteristica comun la monosomia 1p, tres de ellos con patron morfologicobenigno, dos atipicos y 5 malignos. Se realiza un estudio citogenetico y FISH, asi como la determinacionde FA-in en citologia por improntas del tumor. Resultados El estudio demuestra que 8 de las 10 observaciones presentan perdida de expresionde FA-in. En un caso se demostro positividad en un 20% de las celulas. Un caso fue positivo,con actividad demostrada en el 80% de las celulas. Conclusiones El trabajo analiza la relacion entre la falta de expresion de FA-in, la monosomia1p y la agresividad del meningioma. Los resultados apoyan el interes de la determinacion deesta enzima en improntas como un metodo rapido y de interes pronostico.

Association between epidermal growth factor receptor amplification and ADP-ribosylation factor 1 methylation in human glioblastoma.

PurposeGlioblastoma (GB) is the most frequent and most malignant primary brain tumor in adults. Previously, it has been found that both genetic and epigenetic factors may play critical roles in its etiology and prognosis. In addition, it has been found that the epidermal growth factor receptor gene (EGFR) is frequently over-expressed and amplified in primary GBs. Here, we assessed the promoter methylation status of 10 genes relevant to GB and explored associations between these findings and the EGFR gene amplification status.MethodsTumor samples were obtained from 36 patients with primary GBs. In addition, 6 control specimens were included from patients who were operated for diseases other than brain tumors. The amplification status of the EGFR gene, and its deletion mutant EGFRvIII, were evaluated using FISH and MLPA, respectively. The IDH1/2 gene mutation status was verified using Sanger sequencing. A commercial DNA methylation kit was used to assess the promoter methylation status of 10 pre-selected genes. Metabolic profiles were measured using HR-MAS NMR spectroscopy. The EGFR and ARF1 mRNA expression levels were quantified using qRT-PCR.ResultsOf the 10 genes analyzed, we found that only ARF1 promoter hypermethylation was significantly associated with EGFR gene amplification. ARF1 is a GTPase that is involved in vesicle trafficking and the Golgi apparatus. Subsequent tumor metabolism measurements revealed a positive association between EGFR amplification and different membrane precursors and methyl-donor metabolites. Finally, we found that EGFR gene amplifications were associated with distinct tumor infiltration patterns, thus representing a putative novel functional association between EGFR gene amplification and ARF1 gene promoter methylation in GB.ConclusionsThe results reported here provide a basis for a new hypotheses connecting EGFR gene amplification in GB cells with ARF1 gene promoter methylation, vesicle trafficking, membrane turnover and tumor metabolism. The mechanism(s) underlying these connections and their functional consequences remain to be established.