[Medulloblastoma. Pathology]. / Médulloblastome. Anatomie pathologique.

Medulloblastomas, embryonal neuroepithelial tumors developed in the cerebellum or brain stem, are mainly observed in childhood. The treatment of WHO-Grade IV tumors depends on stratifications that are usually based on postoperative data, histopathological subtype, tumor extension and presence of MYC or NMYC amplifications. Recently, molecular biology studies, based on new technologies (i.e. sequencing, transcriptomic, methylomic) have introduced genetic subtypes integrated into the latest WHO-2016 neuropathological classification. According to this classification, the three genetic groups WNT, SHH, with or without mutated TP53 gene, and non-WNT/non-SHH, comprising subgroups 3 and 4, are recalled in this review. The contribution of immunohistochemistry to define these groups is specified. The four histopathological groups are detailed in comparison to the WHO-2007 classification and the molecular data: classic medulloblastoma, desmoplastic/nodular medulloblastoma, medulloblastoma with extensive nodularity, and large cell/anaplastic medulloblastoma. The groups defined on genetic and histopathological grounds are not strictly concordant. Depending on the age of the patients, their correlations are different, as well as their role in the management and prognosis of these tumors. Other embryonal tumors, for which new classifications are in progress and gliomas may be confused with a medulloblastoma and the elements of the differential diagnosis of these entities are discussed. This evolution in classification fully justifies ongoing structuring procedures such as histopathological review (RENOCLIP) and the organization of molecular biology platforms.

A new HPF specimen carrier adapter for the use of high-pressure freezing with cryoscanning electron microscope: two applications: stearic acid organization in a hydroxypropyl methylcellulose matrix and mice myocardium.

Cryogenic transmission electron microscopy of high-pressure freezing (HPF) samples is a well-established technique for the analysis of liquid containing specimens. This technique enables observation without removing water or other volatile components. The HPF technique is less used in scanning electron microscopy (SEM) due to the lack of a suitable HPF specimen carrier adapter. The traditional SEM cryotransfer system (PP3000T Quorum Laughton, East Sussex, UK; Alto Gatan, Pleasanton, CA, USA) usually uses nitrogen slush. Unfortunately, and unlike HPF, nitrogen slush produces water crystal artefacts. So, we propose a new HPF specimen carrier adapter for sample transfer from HPF system to cryogenic-scanning electronic microscope (Cryo-SEM). The new transfer system is validated using technical two applications, a stearic acid in hydroxypropyl methylcellulose solution and mice myocardium. Preservation of samples is suitable in both cases. Cryo-SEM examination of HPF samples enables a good correlation between acid stearic liquid concentration and acid stearic occupation surface (only for homogeneous solution). For biological samples as myocardium, cytoplasmic structures of cardiomyocyte are easily recognized with adequate preservation of organelle contacts and inner cell organization. We expect this new HPF specimen carrier adapter would enable more SEM-studies using HPF.

A French retrospective study on clinical outcome in 102 choroid plexus tumors in children.

The aim of this study was to review and describe therapeutic approaches in children with choroid plexus tumor (CPT) based on a nationwide series. The World Health Organization classification subdivides these rare tumors into three histological subtypes corresponding to three grades of malignancy: low grade (grade I) choroid plexus papilloma (CPP), intermediate grade (grade II) atypical choroid plexus papilloma (aCPP) and high grade (grade III) choroid plexus carcinoma (CPC). This retrospective study included 102 French children younger than 18 years, treated from 2000 to 2012: 54 CPP, 26 aCPP and 22 CPC. The 5 year overall survival was 100% in CPP, 96.2% in aCPP and 64.7% in CPC. In patients with localized disease, complete surgical resection was achieved in 48/52 CPP, 20/26 aCPP and 7/14 CPC. In this group, patients with complete surgical resection had better event free survival than patients with partial resection (88.9 vs. 41.6%). 28 patients (1 CPP, 6 aCPP and 22 CPC) had adjuvant chemotherapy. 2 aCPP and 9 CPC had radiotherapy. We underlined the need for a central histological review to accurately analyze clinical data; we reported a much higher overall survival for CPC than in most previous CPT series probably including atypical teratoid rhabdoid tumors. In our series, the 5 years overall survival in CPC (64.7%) was higher than event free survival (25.2%) and could be interpreted as a clue for the efficiency of adjuvant/salvage therapy even if the heterogeneity of applied treatments in this retrospective series does not allow for meaningful statistical comparisons.

How biophysical in vivo testing techniques can be used to characterize full thickness skin equivalents.

BACKGROUND: The reliability of the biophysical properties of skin equivalents (SEs) remains a challenge for medical applications and for product efficacy tests following the European Directive 2003/15/EC2 on the prohibition of animal experiments for cosmetic products. METHODS: We propose to adapt the biophysical in vivo testing techniques to compare full thickness model growth vs. time. The interest in using such techniques lies in possible comparisons between in vivo and in vitro skin as well as monitoring samples over the culture time. RESULTS: High frequency ultrasound technique, optical coherence tomography (OCT), and laser scanning microscopy were used to analyze SEs morphology at days D42 and D60 whereas their microstructure was assessed through transmission electron microscopy and classical histology. A correlation between these observations and mechanical measurements has been proposed so as to underline the consequence of both the development of the dermis elastic fibers and the epidermis differentiation. CONCLUSION: Ultrasounds measurements show a highly homogeneous dermis whereas the OCT technique clearly distinguishes the stratum corneum and the living epidermis. The increase in the thicknesses of these layers as well as the growth in elastin and collagen fibers results in strong modifications of the samples mechanical properties.

Improvement of the cytological diagnostic accuracy of follicular thyroid lesions by the use of the Ki-67 proliferative index in addition to cytokeratin-19 and HBME-1 immunomarkers: a study of 61 cases of liquid-based FNA cytology with histological controls.

OBJECTIVES: To evaluate HBME-1, cytokeratin-19 (CK-19) and Ki-67 immunomarkers in order to increase the diagnostic accuracy of preoperative thyroid fine needle aspiration (FNA) cytology. METHODS: Immunocytochemistry against HBME-1, CK-19 and Ki-67 was performed on 123 thyroid FNAs processed by liquid-based cytology (LBC). Statistical analysis was carried out on 61 cases with histological control and sufficient material for one or more of the three markers. The Bethesda System was used for cytological diagnosis. RESULTS: Taking into account all the cytological categories, with a cut-off of 30% of positive cells, HBME-1 (n = 47) and CK-19 (n = 53) showed a sensitivity for malignancy of 66.7% (95% confidence interval, 53.2-80.1) and 90.5% (82.6-98.4) and a specificity of 90.6% (82.3-99) and 75% (63.3-86.7), respectively. For Ki-67 (n = 54) with a cut-off of 1% of positive cells, the sensitivity was 85.0% (75.5-94.5) and the specificity 70.6% (58.4-82.7). In the follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) category (n = 37), which was the focus of the study, papillary thyroid carcinomas (PTCs) were less numerous (four cases, three of which were the follicular variant), the positivity of the three immunomarkers combined showed an overall accuracy of 91% (21/23). The mean percentage of Ki-67-positive cells was increased in malignant lesions, with the exception of follicular variant PTCs: 16% ± 15.6% in two follicular carcinomas, 4.8% ± 3.2% in 13 classical PTCs, 1% ± 1.2% in five follicular variant PTCs and 0.5% ± 1.9% in 34 non-malignant lesions. CONCLUSIONS: Immunocytochemistry using HBME-1, CK-19 and the Ki-67 proliferative index increased the diagnostic accuracy of FNA in the FN/SFN category of the Bethesda System, which may help to distinguish lesions in this category with a low or high risk of malignancy. Thus, clinical management would be improved.

Dual roles of hemidesmosomal proteins in the pancreatic epithelium: the phosphoinositide 3-kinase decides.

Given the failure of chemo- and biotherapies to fight advanced pancreatic cancer, one major challenge is to identify critical events that initiate invasion. One priming step in epithelia carcinogenesis is the disruption of epithelial cell anchorage to the basement membrane which can be provided by hemidesmosomes (HDs). However, the existence of HDs in pancreatic ductal epithelium and their role in carcinogenesis remain unexplored. HDs have been explored in normal and cancer pancreatic cells, and patient samples. Unique cancer cell models where HD assembly can be pharmacologically manipulated by somatostatin/sst2 signaling have been then used to investigate the role and molecular mechanisms of dynamic HD during pancreatic carcinogenesis. We surprisingly report the presence of mature type-1 HDs comprising the integrin α6ß4 and bullous pemphigoid antigen BP180 in the human pancreatic ductal epithelium. Importantly, HDs are shown to disassemble during pancreatic carcinogenesis. HD breakdown requires phosphoinositide 3-kinase (PI3K)-dependent induction of the matrix-metalloprotease MMP-9, which cleaves BP180. Consequently, integrin α6ß4 delocalizes to the cell-leading edges where it paradoxically promotes cell migration and invasion through S100A4 activation. As S100A4 in turn stimulates MMP-9 expression, a vicious cycle maintains BP180 cleavage. Inactivation of this PI3K-MMP-9-S100A4 signaling loop conversely blocks BP180 cleavage, induces HD reassembly and inhibits cell invasion. We conclude that mature type-1 HDs are critical anchoring structures for the pancreatic ductal epithelium whose disruption, upon PI3K activation during carcinogenesis, provokes pancreatic cancer cell migration and invasion.

Investigation of the significance of Oil Red O-positive macrophage excess in bronchoalveolar lavage fluid during HIV infection.

OBJECTIVE: To assess the significance of increased levels of Oil Red O-positive macrophages (ORO-PM) in bronchoalveolar lavage fluids (BALFs) from HIV-positive patients. METHODS: Cytological data for seventy BALF samples from 66 consecutive HIV-infected patients were analysed according to antiretroviral therapy regimen, presence of Pneumocystis jiroveci infection, blood CD4(+) T cell count, HIV-1 viral load and plasma lipid levels. Non-parametric tests were used to compare the values between groups. RESULTS: The percentages of ORO-PM were high in this group: 40% [6-80] (median [interquartile range]). They were positively correlated with the BALF total cell count, 21% [5-48.5] for <300 cells/mm(3) and 60% [26.5-80] for >300 cells/mm(3) (P<0.01) but inversely correlated with the percentage of BALF lymphocytes, 50% [20-80] for <15% lymphocytes and 11.5% [2-47] for ≥15% lymphocytes (P<0.01). Antiretroviral therapy with or without protease inhibitors, plasma lipid levels, HIV-1 viral load, blood CD4(+) T cell count or presence of a Pneumocystis jiroveci infection were not correlated with the ORO-PM status. CONCLUSION: Significantly increased numbers of ORO-PM were correlated with high total cell counts and low lymphocyte counts in BALF, irrespective of disease activity or treatment. Extended work on a larger series of patients needs to be conducted.

Utility of Ki67 immunostaining in the grading of pineal parenchymal tumours: a multicentre study.

AIMS: Pineal parenchymal tumours (PPTs) are rare neoplasms that are divided into pineocytoma (PC), pineoblastoma (PB) and PPT of intermediate differentiation (PPTID). Factors affecting the survival of patients with PPTs are morphological subtype and histological grading according to mitotic index and neurofilament immunostaining. Grading criteria to distinguish PPTIDs are difficult to define, particularly when using small specimens. The Ki67 labelling index (LI) might be helpful in distinguishing between grade II and III PPTIDs. Our study was performed to assess the predictive value of the Ki67 LI in a large cooperative series of PPTs and to evaluate whether inclusion of this data would improve and refine the World Health Organization classification. METHODS: A retrospective analysis of 33 PPTs was performed. The histological features of the tumours were reviewed and Ki67 LI scoring was evaluated by immunohistochemistry. Data were correlated with the patients' survival. RESULTS: The mean Ki67 LI was significantly different for tumour grades (0 in PC, 5.2 ± 0.4 in PPTID grade II, 11.2 ± 2.0 in PPTID grade III, 36.4 ± 6.2 in PB; P < 0.0001). However, there was no statistically significant difference in either overall or disease-free survival evaluated by the Kaplan-Meier method for patients with different grade tumours or Ki67 LI, possibly due to the different clinical management of patients in different centres. CONCLUSIONS: The Ki67 LI may be a useful additional tool for grading PPTs, more particularly in small tumour samples.

DNA replication stress response involving PLK1, CDC6, POLQ, RAD51 and CLASPIN upregulation prognoses the outcome of early/mid-stage non-small cell lung cancer patients.

Lung cancer is the leading cause of cancer deaths worldwide. Clinical staging classification is generally insufficient to provide a reliable prognosis, particularly for early stages. In addition, prognostic factors are therefore needed to better forecast life expectancy and optimize adjuvant therapeutic strategy. Recent evidence indicates that alterations of the DNA replication program contribute to neoplasia from its early stages and that cancer cells are frequently exposed to endogenous replication stress. We therefore hypothesized that genes involved in the replication stress response may represent an under-explored source of biomarkers. Expressions of 77 DNA replication-associated genes implicated in different aspects of chromosomal DNA replication, including licensing, firing of origins, elongation, replication fork maintenance and recovery, lesion bypass and post-replicative repair were determined in primary tumors and adjacent normal tissues from 93 patients suffering from early- or mid-stage non-small cell lung cancer (NSCLC). We then investigated a statistically significant interaction between gene expressions and survival of early-stage NSCLC patients.The expression of five genes, that is, POLQ, PLK1, RAD51, CLASPIN and CDC6 was associated with overall, disease-free and relapse-free survival. The expression levels are independent of treatment and stage classification. Except RAD51, their prognostic role on survival persists after adjustment on age, sex, treatment, stage classification and conventional proliferation markers, with a hazard ratio of 36.3 for POLQ (95%CI 2.6-517.4, P=0.008), 23.5 for PLK1 (95%CI 1.9-288.4, P=0.01), 20.7 for CLASPIN (95%CI 1.5-275.9, P=0.02) and 18.5 for CDC6 (95%CI 1.3-267.4, P=0.03). We also show that a five-gene signature including POLQ, PLK1, RAD51, CLASPIN and CDC6 separates patients into low- and high-risk groups, with a hazard ratio of 14.3 (95% CI 5.1-40.3, P<0.001). This 'replication stress' metamarker may be a reliable predictor of survival for NSCLC, and may also help understand the molecular mechanisms underlying tumor progression.

Cerebral amyloid angiopathy and microhemorrhages after amyloid beta vaccination: case report and brief review.

After the interruption of the international multicenter Phase 2 clinical trial with active immunotherapy based on synthetic Abeta42 (AN1792), few reports about the neuropathological findings in those patients and those from the Phase 1 clinical trial were published. These reports described some pathological similarities among the patients such as a reduction in the burden of amyloid plaques, the reactions of microglia/macrophages and the persistence of neurofibrillary tangles and neuropil threads. In addition, a lymphocytic inflammatory infiltrate as well as white matter lesions were present in some cases with meningoencephalitis. In both animal models of vaccination, as well as some vaccinated patient samples, there appears to be a correlation between vaccination and hemorrhages. Subsequently, two series reports concerning 8 patients from the Phase 1 initial trial showed that immunization with Abeta42 seemed to result in clearance of amyloid plaques, but did not prevent progressive neurodegeneration and that it increased vessel wall amyloid angiopathy as well as cortical microhemorrhages. Recent clinical data gave further encouraging results regarding vaccination in humans demonstrating that long term follow-up of patients from the second clinical trial revealed reduced functional decline, at least, in antibody responders. Here we describe a patient diagnosed with Alzheimer's disease who also participated in the Phase 2 clinical trial. A neuropathological examination confirmed Alzheimer's disease without meningoencephalitis and revealed a severe amyloid angiopathy with frequent microhemorrhages, the decrease of amyloid load being difficult to ascertain. Our results are in agreement with previous studies and confirm the presence of severe amyloid angiopathy after vaccination. The latter may be a transient phenomenon depending on the degree of immune response and the pathological stage of the disease when the patient underwent treatment. In addition, our vaccinated case also demonstrated microhemorrhages and microinfarcts which were already noticed to occur with a higher density in immunized Alzheimer's disease patients.

Desmoplastic infantile astrocytoma with benign histological phenotype and multiple intracranial localizations at presentation.

Desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma (DIG) are rare intracranial tumors that mostly occur in the first 2 years of life and involve superficial cerebral cortex. Despite the large size of these lesions and some worrisome histological and radiological features, prognosis is generally favorable after gross total resection. We report an original observation of a desmoplastic infantile astrocytoma in a 5-year-old boy with multiple localizations on initial presentation, including the unusual subtentorial region. Magnetic resonance imaging showed a temporal tumor with prepontine and interpeduncular extension, and two other distinct localizations in cisterna magna and left cerebellar hemisphere. Leptomeningeal enhancements were present around the basal cistern. The surgical samples, corresponding exclusively to subtentorial lesions, were devoid of anaplastic features; the temporal lesion was untouched because of the interpeduncular extension. Adjuvant chemotherapy was applied, with shrinkage of lesions. DIA and DIG are more generally unifocal at initial presentation. When the tumor is large, multilobular involvement is common, but multiple location of DIG is, on the contrary, very rare. Previously, only five cases of DIG/DIA located in two or more separate locations have been published. We report the sixth, and first noninfantile, case of DIA/DIG with multifocal initial presentation.

[Domino transplantation of a living-donor kidney graft affected by thrombotic microangiopathy: surgical aspects]. / Transplantation domino à partir d'un donneur vivant d'un rein greffé atteint d'une micro-angiopathie thrombotique: aspects chirurgicaux.

We report surgical aspects of the first case of retransplantation of a kidney initially retrieved from a cadaveric donor, then on a first recipient which developed a recurrent severe and intractable thrombotic microangiopathy on the allograft.

[Clinical course and outcome in French adults with Moyamoya disease]. / Aspects cliniques et évolutifs de la maladie de Moyamoya chez des adultes français.

BACKGROUND AND PURPOSE: Moyamoya disease is rare among non-Asian populations and its clinical features are ill-defined. We report 12 new cases of Moyamoya disease in French, non-Asian adults. METHODS: We identified adults with Moyamoya disease managed at a French University Hospital from 1998 through 2006. We reviewed baseline clinical and radiological data and collected follow-up data between March and June 2008. The risk of recurrent stroke was determined using the Kaplan-Meier method. RESULTS: Twelve patients, 10 women and two men, were included. The mean age at baseline was 31.1 years. The initial clinical manifestation was ischemic stroke in 10 patients. The disease was clinically asymptomatic in two patients. The mean follow-up in the 10 symptomatic patients was 52.4 months. Only one patient was surgically treated. The one and five-year risk of recurrent stroke were both 50%. At the end of the follow-up, one patient was dead, four patients had no functional impairment (grade 0-1 on the Rankin scale), and seven patients had moderate functional impairment (grade 2-3 on the Rankin scale). A cognitive dysfunction as identified by failure on the Trail Making Test part B was found in six of ten patients evaluated. CONCLUSION: Moyamoya disease in this cohort of French, non-Asian adults was associated with high rates of both recurrent stroke and cognitive impairment. The findings suggest that Moyamoya disease in non-Asian adults is a potentially severe disease.

[Radiation-induced cavernoma: two cases]. / Cavernomes radio-induits. A propos de deux cas.

Only a few cases of cavernomas induced by radiation treatment, 78 patients, have been reported in the literature. The prevalence may be underestimated. Cavernomas occur several years after radiotherapy for brain neoplasia. Medulloblastoma, glioma and acute lymphoblastic lymphoma are commonly diagnosed and treated in childhood, generally in males. We report new cases of cavernomas induced by radiation treatment. The first case was a 55-year-old man given radiation and chemotherapy for frontal astrocytoma at the age of 46. The second concerned a 30-year-old woman treated by radiation and surgery for brainstem medulloblastoma at the age of four. Epidemiological and pathogenic features of radiation-induced cavernoma are discussed.

Comparison of extent of tau pathology in patients with frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), frontotemporal lobar degeneration with Pick bodies and early onset Alzheimer's disease.

In order to gain insight into the pathogenesis of frontotemporal lobar degeneration (FTLD), the mean tau load in frontal cortex was compared in 34 patients with frontotemporal dementia linked to chromosome 17 (FTDP-17) with 12 different mutations in the tau gene (MAPT), 11 patients with sporadic FTLD with Pick bodies and 25 patients with early onset Alzheimer's disease (EOAD). Tau load was determined, as percentage of tissue occupied by stained product, by image analysis of immunohistochemically stained sections using the phospho-dependent antibodies AT8, AT100 and AT180. With AT8 and AT180 antibodies, the amount of tau was significantly (P < 0.001 in each instance) less than that in EOAD for both FTDP-17 (8.5% and 10.0% respectively) and sporadic FTLD with Pick bodies (16.1% and 10.0% respectively). With AT100, the amount of tau detected in FTDP-17 was 54% (P < 0.001) of that detected in EOAD, but no tau was detected in sporadic FTLD with Pick bodies using this particular antibody. The amount of insoluble tau deposited within the brain in FTDP-17 did not depend in any systematic way upon where the MAPT mutation was topographically located within the gene, or on the physiological or structural change generated by the mutation, regardless of which anti-tau antibody was used. Not only does the amount of tau deposited in the brain differ between the three disorders, but the pattern of phosphorylation of tau also varies according to disease. These findings raise important questions relating to the role of aggregated tau in neurodegeneration - whether this represents an adaptive response which promotes the survival of neurones, or whether it is a detrimental change that directly, or indirectly, brings about the demize of the affected cell.

Immunodetection of SV40 large T antigen in human central nervous system tumours.

BACKGROUND/AIMS: DNA sequences from Simian virus 40 (SV40) have been previously isolated from various human tumours of the central nervous system (CNS). This study aimed to investigate a series of tumours of the CNS for the expression of the SV40 large T antigen (Tag), which is an oncogenic protein of the virus. METHODS: A French series of 82 CNS tumours was investigated for Tag expression using a monoclonal antibody and immunohistochemistry. A Tag positive hepatocellular carcinoma cell line from transgenic mice and a kidney biopsy from a patient infected by SV40 were used as positive controls. RESULTS: None of the tumours (20 ependymomas, 20 glioblastomas, 12 oligodendrogliomas, three plexus choroid adenomas, two plexus choroid carcinomas, 15 meningiomas, and 10 medulloblastomas) contained SV40 Tag positive cells. CONCLUSIONS: The lack of SV40 Tag in 82 CNS tumours of various types is at variance with previous studies from different countries, and suggests that the virus may not be an important factor in CNS tumorigenesis, at least in French cases.

Detection of human cytomegalovirus genome and gene products in central nervous system tumours.

Human cytomegalovirus (HCMV) genome and related proteins have been reported in a great proportion of malignant gliomas. However, these results are unexpected since HCMV is not known as an oncogenic virus. By immunohistochemistry (with an anti-IE1 monoclonal antibody) and in situ hybridisation (with biotinylated DNA probes) on tissue microarrays and frozen sections, we investigated a French series of central nervous system (CNS) tumours, including 97 glioblastomas. In 10 cases of glioblastoma, rare astrocyte-like cells, admixed with tumour cells, stained positively for HCMV and in one case a doubtful staining of rare cells was noticed. This may indicate a reactivation of the virus under local immunosuppression but none of the cases of CNS tumours (n=132) contained HCMV genomes and/or proteins in a significant proportion of tumour cells. Our results strongly suggest that HCMV is unlikely to be implicated in the development of human malignant gliomas, at least in French cases.