A Case of Whipple Disease With Cutaneous Manifestations.

ABSTRACT: Whipple disease (WD) is a rare bacterial infectious disease that is classically characterized by years of arthralgia, followed by malabsorption, diarrhea, and weight loss. However, WD may manifest in virtually any organ system, and patients with WD rarely develop subcutaneous erythema nodosum-like lesions. We report a case of a 51-year-old man diagnosed with WD who subsequently developed widely distributed erythematous subcutaneous nodules after 5 months of antibiotic therapy.

Clonal selection drives genetic divergence of metastatic medulloblastoma.

Medulloblastoma, the most common malignant paediatric brain tumour, arises in the cerebellum and disseminates through the cerebrospinal fluid in the leptomeningeal space to coat the brain and spinal cord. Dissemination, a marker of poor prognosis, is found in up to 40% of children at diagnosis and in most children at the time of recurrence. Affected children therefore are treated with radiation to the entire developing brain and spinal cord, followed by high-dose chemotherapy, with the ensuing deleterious effects on the developing nervous system. The mechanisms of dissemination through the cerebrospinal fluid are poorly studied, and medulloblastoma metastases have been assumed to be biologically similar to the primary tumour. Here we show that in both mouse and human medulloblastoma, the metastases from an individual are extremely similar to each other but are divergent from the matched primary tumour. Clonal genetic events in the metastases can be demonstrated in a restricted subclone of the primary tumour, suggesting that only rare cells within the primary tumour have the ability to metastasize. Failure to account for the bicompartmental nature of metastatic medulloblastoma could be a major barrier to the development of effective targeted therapies.

Radiological Growth Patterns of Prolactinomas and Nonfunctioning Adenomas.

OBJECTIVES: To compare growth patterns of nonfunctioning and prolactin-producing pituitary macroadenomas, and to find whether their specific growth patterns are associated with clinically significant effects on vision. MATERIALS AND METHODS: From our comprehensive provincial neuropituitary registry, we retrospectively identified 35 randomly selected patients each with nonfunctioning adenomas and prolactinomas >10 mm in any dimension. MRI scans were analyzed to determine the superior and inferior growth, volume, and maximum craniocaudal height of the adenomas. Patients underwent visual field testing at diagnosis. Continuous variables were compared using Student's t test, the Mann-Whitney U test, and ANOVA. Categorical variables were compared using the chi-square test. RESULTS: The mean height of prolactinomas (23.2±11.3 mm) was similar to nonfunctioning adenomas (22.3±9.3 mm, p=0.8), and so were mean tumor volumes (prolactinoma=5.9±8 ml vs. nonfunctioning adenoma=4.8±5 ml, p=0.47). However, the mean suprasellar growth for prolactinomas was 2.9±5.3 mm and 7.3±4.7 mm for nonfunctioning adenomas (p<0.001), and the mean infrasellar growth was 10.2±8.0 and 5.0±6.6 mm, respectively (p=0.04). The inferior growth pattern of prolactinomas was associated with a significantly lower likelihood of having visual field abnormalities (11.4 vs. 57.1%, p<0.001). CONCLUSIONS: Prolactinomas have predominantly inferior growth compared to nonfunctioning adenomas and are less likely to cause vision changes.

A role for matrix remodelling proteins in invasive and malignant meningiomas.

AIMS: Meningiomas are one of the most common brain tumours in adults. Invasive and malignant meningiomas present a significant therapeutic challenge due to high recurrence rates and invasion into surrounding bone, brain, neural and soft tissues. Understanding the molecular mechanism of invasion could help in designing novel therapeutic approaches in order to prevent the need for repeat surgery, decrease morbidity and improve patient survival. The aim of this study was to identify the key factors and underlying mechanisms which govern invasive properties of meningiomas. METHODS: Formalin-fixed paraffin-embedded (FFPE) as well as frozen tumour tissues from bone-invasive, non-invasive and malignant meningiomas were used for RNA microarray, quantitative real-time PCR or Western blot analyses. Malignant meningioma cell lines (F5) were subject to MMP16 downregulation or overexpression and used for in vitro and in vivo functional assays. Subdural xenograft meningioma tumours were generated to study the invasion of tumour cells into brain parenchyma using cell lines with altered MMP16 expression. RESULTS: We establish that the expression level of MMP16 was significantly elevated in both bone-invasive and brain invasive meningiomas. Gain- and loss-of-function experiments indicated a role for MMP16 in meningioma cell movement, invasion and tumour cell growth. Furthermore, MMP16 was shown to positively regulate MMP2, suggesting this mechanism may modulate meningioma invasion in invasive meningiomas. CONCLUSIONS: Overall, the results support a role for MMP16 in promoting invasive properties of the meningioma tumours. Further studies to explore the potential value for clinical use of matrix metalloproteinases inhibitors are warranted.

The role of drebrin in glioma migration and invasion.

Glioblastoma (GBM) is the most common primary brain tumor in adults. Despite current advances in therapy consisting of surgery followed by chemotherapy and radiation, the overall survival rate still remains poor. Therapeutic failures are partly attributable to the highly infiltrative nature of tumor adjacent to normal brain parenchyma. Recently, evidence is mounting to suggest that actin cytoskeleton dynamics are critical components of the cell invasion process. Drebrin is an actin-binding protein involved in the regulation of actin filament organization, and plays a significant role in cell motility; however, the role of drebrin in glioma cell invasiveness has not yet been fully elucidated. Therefore, this study was aimed to clarify the role of drebrin in glioma cell morphology and cell motility. Here we show that drebrin is expressed in glioma cell lines and in operative specimens of GBM. We demonstrate that stable overexpression of drebrin in U87 cells leads to alterations in cell morphology, and induces increased invasiveness in vitro while knockdown of drebrin in U87 cells by small interfering RNA (siRNA) decreases invasion and migration. In addition, we show that depletion of drebrin by siRNA alters glioma cell morphology in A172 GBM cell line. Our results suggest that drebrin contributes to the maintenance of cell shape, and may play an important role in glioma cell motility.

Methylation of the TERT promoter and risk stratification of childhood brain tumours: an integrative genomic and molecular study.

BACKGROUND: Identification of robust biomarkers of malignancy and methods to establish disease progression is a major goal in paediatric neuro-oncology. We investigated whether methylation of the TERT promoter can be a biomarker for malignancy and patient outcome in paediatric brain tumours. METHODS: For the discovery cohort, we used samples obtained from patients with paediatric brain tumours and individuals with normal brain tissues stored at the German Cancer Research Center (Heidelberg, Germany). We used methylation arrays for genome-wide assessment of DNA. For the validation cohort, we used samples obtained from several tissues for which full clinical and follow-up data were available from two hospitals in Toronto (ON, Canada). We did methylation analysis using quantitative Sequenom and pyrosequencing of an identified region of the TERT promoter. We assessed TERT expression by real-time PCR. To establish whether the biomarker could be used to assess and predict progression, we analysed methylation in paired samples of tumours that transformed from low to high grade and from localised to metastatic, and in choroid plexus tumours of different grades. Finally, we investigated overall survival in patients with posterior fossa ependymomas in which the identified region was hypermethylated or not. All individuals responsible for assays were masked to the outcome of the patients. FINDINGS: Analysis of 280 samples in the discovery cohort identified one CpG site (cg11625005) in which 78 (99%) of 79 samples from normal brain tissues and low-grade tumours were not hypermethylated, but 145 (72%) of 201 samples from malignant tumours were hypermethylated (>15% methylated; p<0.0001). Analysis of 68 samples in the validation cohort identified a subset of five CpG sites (henceforth, upstream of the transcription start site [UTSS]) that was hypermethylated in all malignant paediatric brain tumours that expressed TERT but not in normal tissues that did not express TERT (p<0.0001). UTSS had a positive predictive value of 1.00 (95% CI 0.95-1.00) and a negative predictive value of 0.95 (0.87-0.99). In two paired samples of paediatric gliomas, UTSS methylation increased during transformation from low to high grade; it also increased in two paired samples that progressed from localised to metastatic disease. Two of eight atypical papillomas that had high UTSS methylation progressed to carcinomas, while the other six assessed did not progress or require additional treatment. 5-year overall survival was 51% (95% CI 31-71) for 25 patients with hypermethylated UTSS posterior fossa ependymomas and 95% (86-100) for 20 with non-hypermethylated tumours (p=0.0008). 5-year progression-free survival was 86% (68-100) for the 25 patients with non-hypermethylated UTSS tumours and 30% (10-50) for those with hypermethylated tumours (p=0.0008). INTERPRETATION: Hypermethylation of the UTSS region in the TERT promoter is associated with TERT expression in cancers. In paediatric brain tumours, UTSS hypermethylation is associated with tumour progression and poor prognosis. This region is easy to amplify, and the assay to establish hypermethylation can be done on most tissues in most clinical laboratories. Therefore the UTSS region is a potentially accessible biomarker for various cancers. FUNDING: The Canadian Institute of Health Research and the Terry Fox Foundation.

Recurrence patterns across medulloblastoma subgroups: an integrated clinical and molecular analysis.

BACKGROUND: Recurrent medulloblastoma is a therapeutic challenge because it is almost always fatal. Studies have confirmed that medulloblastoma consists of at least four distinct subgroups. We sought to delineate subgroup-specific differences in medulloblastoma recurrence patterns. METHODS: We retrospectively identified a discovery cohort of all recurrent medulloblastomas at the Hospital for Sick Children (Toronto, ON, Canada) from 1994 to 2012 (cohort 1), and established molecular subgroups using a nanoString-based assay on formalin-fixed paraffin-embedded tissues or frozen tissue. The anatomical site of recurrence (local tumour bed or leptomeningeal metastasis), time to recurrence, and survival after recurrence were assessed in a subgroup-specific manner. Two independent, non-overlapping cohorts (cohort 2: samples from patients with recurrent medulloblastomas from 13 centres worldwide, obtained between 1991 and 2012; cohort 3: samples from patients with recurrent medulloblastoma obtained at the NN Burdenko Neurosurgical Institute [Moscow, Russia] between 1994 and 2011) were analysed to confirm and validate observations. When possible, molecular subgrouping was done on tissue obtained from both the initial surgery and at recurrence. RESULTS: Cohort 1 consisted of 30 patients with recurrent medulloblastomas; nine with local recurrences, and 21 with metastatic recurrences. Cohort 2 consisted of 77 patients and cohort 3 of 96 patients with recurrent medulloblastoma. Subgroup affiliation remained stable at recurrence in all 34 cases with available matched primary and recurrent pairs (five pairs from cohort 1 and 29 pairs from cohort 2 [15 SHH, five group 3, 14 group 4]). This finding was validated in 17 pairs from cohort 3. When analysed in a subgroup-specific manner, local recurrences in cohort 1 were more frequent in SHH tumours (eight of nine [89%]) and metastatic recurrences were more common in group 3 and group 4 tumours (17 of 20 [85%] with one WNT, p=0·0014, local vs metastatic recurrence, SHH vs group 3 vs group 4). The subgroup-specific location of recurrence was confirmed in cohort 2 (p=0·0013 for local vs metastatic recurrence, SHH vs group 3 vs group 4,), and cohort 3 (p<0·0001). Treatment with craniospinal irradiation at diagnosis was not significantly associated with the anatomical pattern of recurrence. Survival after recurrence was significantly longer in patients with group 4 tumours in cohort 1 (p=0·013) than with other subgroups, which was confirmed in cohort 2 (p=0·0075), but not cohort 3 (p=0·70). INTERPRETATION: Medulloblastoma does not change subgroup at the time of recurrence, reinforcing the stability of the four main medulloblastoma subgroups. Significant differences in the location and timing of recurrence across medulloblastoma subgroups have potential treatment ramifications. Specifically, intensified local (posterior fossa) therapy should be tested in the initial treatment of patients with SHH tumours. Refinement of therapy for patients with group 3 or group 4 tumours should focus on metastases.

Mesenchymal glioma stem cells trigger vasectasia-distinct neovascularization process stimulated by extracellular vesicles carrying EGFR.

Targeting neovascularization in glioblastoma (GBM) is hampered by poor understanding of the underlying mechanisms and unclear linkages to tumour molecular landscapes. Here we report that different molecular subtypes of human glioma stem cells (GSC) trigger distinct endothelial responses involving either angiogenic or circumferential vascular growth (vasectasia). The latter process is selectively triggered by mesenchymal (but not proneural) GSCs and is mediated by a subset of extracellular vesicles (EVs) able to transfer EGFR/EGFRvIII transcript to endothelial cells. Inhibition of the expression and phosphorylation of EGFR in endothelial cells, either pharmacologically (Dacomitinib) or genetically (gene editing), abolishes their EV responses in vitro and disrupts vasectasia in vivo. Therapeutic inhibition of EGFR markedly extends anticancer effects of VEGF blockade in mice, coupled with abrogation of vasectasia and prolonged survival. Thus, vasectasia driven by intercellular transfer of oncogenic EGFR may represent a new therapeutic target in a subset of GBMs.

The alternative lengthening of telomere phenotype is significantly associated with loss of ATRX expression in high-grade pediatric and adult astrocytomas: a multi-institutional study of 214 astrocytomas.

Loss-of-function of alpha thalassemia/mental retardation syndrome X-linked (ATRX) protein leads to a phenotype called alternative lengthening of telomeres (ALT) in some tumors. High-grade astrocytomas comprise a heterogeneous group of central nervous system tumors. We examined a large cohort of adult (91) and pediatric (n=88) high-grade astrocytomas as well as lower grade forms (n=35) for immunohistochemical loss of ATRX protein expression and the presence of ALT using telomere-specific fluorescence in situ hybridization, with further correlation to other known genetic alterations. We found that in pediatric high-grade astrocytomas, 29.6% of tumors were positive for ALT and 24.5% were immunonegative for the ATRX protein, these two alterations being highly associated with one another (P<0.0001). In adult high-grade astrocytomas, 26.4% of tumors were similarly positive for ALT, including 80% of ATRX protein immunonegative cases (P<0.0001). Similar frequencies were found in 11 adult low-grade astrocytomas, whereas all 24 pilocytic astrocytomas were negative for ALT. We did not find any significant correlations between isocitrate dehydrogenase status and either ALT positivity or ATRX protein expression in our adult high-grade astrocytomas. In both cohorts, however, the ALT positive high-grade astrocytomas showed more frequent amplification of the platelet-derived growth factor receptor alpha gene (PDGFRA; 45% and 50%, respectively) than the ALT negative counterparts (18% and 26%; P=0.03 for each). In summary, our data show that the ALT and ATRX protein alterations are common in both pediatric and adult high-grade astrocytomas, often with associated PDGFRA gene amplification.

Aberrant patterns of H3K4 and H3K27 histone lysine methylation occur across subgroups in medulloblastoma.

Recent sequencing efforts have described the mutational landscape of the pediatric brain tumor medulloblastoma. Although MLL2 is among the most frequent somatic single nucleotide variants (SNV), the clinical and biological significance of these mutations remains uncharacterized. Through targeted re-sequencing, we identified mutations of MLL2 in 8 % (14/175) of MBs, the majority of which were loss of function. Notably, we also report mutations affecting the MLL2-binding partner KDM6A, in 4 % (7/175) of tumors. While MLL2 mutations were independent of age, gender, histological subtype, M-stage or molecular subgroup, KDM6A mutations were most commonly identified in Group 4 MBs, and were mutually exclusive with MLL2 mutations. Immunohistochemical staining for H3K4me3 and H3K27me3, the chromatin effectors of MLL2 and KDM6A activity, respectively, demonstrated alterations of the histone code in 24 % (53/220) of MBs across all subgroups. Correlating these MLL2- and KDM6A-driven histone marks with prognosis, we identified populations of MB with improved (K4+/K27-) and dismal (K4-/K27-) outcomes, observed primarily within Group 3 and 4 MBs. Group 3 and 4 MBs demonstrate somatic copy number aberrations, and transcriptional profiles that converge on modifiers of H3K27-methylation (EZH2, KDM6A, KDM6B), leading to silencing of PRC2-target genes. As PRC2-mediated aberrant methylation of H3K27 has recently been targeted for therapy in other diseases, it represents an actionable target for a substantial percentage of medulloblastoma patients with aggressive forms of the disease.

Long-term outcomes for adult craniopharyngioma following radiation therapy.

BACKGROUND: We report long-term outcomes in adult patients with craniopharyngioma following surgery and radiation therapy (RT). MATERIAL AND METHODS: Fifty-three patients treated with RT (median, 50 Gy in 25 fractions) between 1980 and 2009 with pathologically confirmed craniopharyngioma were reviewed (53% solid and 47% cystic/solid). The median age was 53 years (range, 22-76), 53% were female, 83% were sub-totally resected, 6% were gross totally resected and 11% had a biopsy and/or cyst aspiration alone. RT was delivered adjuvantly in 53% of patients as opposed to salvage intent upon progression. RESULTS: Median follow-up was seven years (86 months, range, 8-259). The 5- and 10-year progression-free survival (PFS) rates were 85% and 69%, overall survival (OS) rates were 76% and 70%, and cause-specific survival (CSS) rates were both 88%, respectively. Both univariable and multivariable analysis identified age (<53 or ≥53) as a prognostic factor for OS (p =0.0003) and CSS (p =0.05). PFS was observed to be worse in patients with >2 surgeries prior to RT (p =0.01). Neither the intent of radiation or tumor type (cystic vs. solid/cystic) were prognostic or predictive. New endocrinopathies and visual dysfunction were observed in 53% and 17% of patients post-surgery, and in 11% and 6% post-RT, respectively. CONCLUSION: We report long-term favorable PFS, CSS and OS for craniopharyngioma post-RT. We observe age as a significant prognostic factor, however, timing of radiation was not.

Clinical Neuropathology practice guide 6-2013: morphology and an appropriate immunohistochemical screening panel aid in the identification of synovial sarcoma by neuropathologists.

AIMS: Pathologists are under increasing pressure to accurately subclassify sarcomas, yet neuropathologists have limited collective experience with rare sarcoma types such as synovial sarcoma. We reviewed 9 synovial sarcomas affecting peripheral nerve diagnosed by neuropathologists and explored the morphologic and immunohistochemical differences between these and MPNST. Our goal was to make practical recommendations for neuropathologists regarding which spindle cell tumors affecting nerve should be sent for SYT-SSX testing. METHODS: Clinical records and genetics were reviewed retrospectively and central pathology review of 9 synovial sarcomas and 6 MPNST included immunohistochemistry for SOX10, S100, BAF47, CK (lmw, pan, CK7, CK19), EMA, CD34, bcl2, CD99, and neurofilament. RESULTS: Common synovial sarcoma sites were brachial plexus, spinal and femoral nerve, none were "intra-neural", all had the SYTSSX1 translocation, and 6/9 were monophasic with myxoid stroma and distinct collagen. Half of the monophasic synovial sarcomas expressed CK7, CK19 or panCK in a "rare positive cells pattern", 8/9 (89%) expressed EMA, and all were SOX10 immunonegative with reduced but variable BAF47 expression. CONCLUSIONS: We recommend that upon encountering a cellular spindle cell tumor affecting nerve neuropathologists consider the following: 1) SYT-SSX testing should be performed on any case with morphology suspicious for monophasic synovial sarcoma including wiry or thick bands of collagen and relatively monomorphous nuclei; 2) neuropathologists should employ a screening immunohistochemical panel including one of CK7, panCK or CK19, plus EMA, S100 and SOX10, and 3) SYT-SSX testing should be performed on any spindle cell tumor with CK and/or EMA immunopositivity if SOX10 immunostaining is negative or only labels entrapped nerve elements.

Analysis of histomorphology in malignant hyperthermia-susceptible patients.

BACKGROUND: Malignant hyperthermia (MH) is a potentially lethal disorder of skeletal muscle triggered by anesthetic agents. A histomorphological examination of diseased muscle may provide insight into MH pathophysiology, but it is not a routine part of standard-of-care practice for the identification of MH-susceptibility. In this study, we investigated muscle histomorphology in a large cohort of MH-susceptible (MHS) patients and examined its relationship to genotype and phenotype. METHODS: All consenting patients who were identified as MHS based on a caffeine-halothane contracture test (CHCT) performed during 1992-2011 were retrospectively identified and recruited for this study. Results of the histomorphological examination, which is a routine part of our centre-specific practice, were reviewed. Patient demographics, MH proband status, histological features, CHCTs, and genetic results for MH-causative mutations were summarized. RESULTS: Seven of the 399 patients classified as MHS had histological characteristics consistent with central core disease, and one patient was a carrier of Duchenne's muscular dystrophy. Eighty-six (22%) patients had histological abnormalities, and five (6%) of these had evidence of "frank" myopathy. No histologic abnormalities were consistent among the MHS patients; however, a higher proportion of MH probands had abnormal histomorphology compared with the general MHS population, and patients with evidence of "frank" myopathy showed similarities in clinical history, biochemistry, CHCT, and genetic testing. CONCLUSION: Despite the inability of the histomorphological examination to identify consistent features in MHS patients, histology may serve as a potential adjunct to CHCT and aid in the identification of other myopathies. Nevertheless, the specifics of its utility ought to be assessed in other studies and by way of formal cost-effectiveness analysis.

Proteins involved in regulating bone invasion in skull base meningiomas.

BACKGROUND: Bone invasive skull base meningiomas are a subset of meningiomas that present a unique clinical challenge due to brain and neural structure involvement and limitations in complete surgical resection, resulting in higher recurrence and need for repeat surgery. To date, the pathogenesis of meningioma bone invasion has not been investigated. We investigated immunoexpression of proteins implicated in bone invasion in other tumor types to establish their involvement in meningioma bone invasion. METHODS: Retrospective review of our database identified bone invasive meningiomas operated on at our institution over the past 20 years. Using high-throughput tissue microarray (TMA), we established the expression profile of osteopontin (OPN), matrix metalloproteinase-2 (MMP2), and integrin beta-1 (ITGB1). Differential expression in tumor cell and vasculature was evaluated and comparisons were made between meningioma anatomical locations. RESULTS: MMP2, OPN, and ITGB1 immunoreactivity was cytoplasmic in tumor and/or endothelial cells. Noninvasive transbasal meningiomas exhibited higher vascular endothelial cell MMP2 immunoexpression compared to invasive meningiomas. We found higher expression levels of OPN and ITGB1 in bone invasive transbasal compared to noninvasive meningiomas. Strong vascular ITGB1 expression extending from the endothelium through the media and into the adventitia was found in a subset of meningiomas. CONCLUSIONS: We have demonstrated that key proteins are differentially expressed in bone invasive meningiomas and that the anatomical location of bone invasion is a key determinant of expression pattern of MMP1, OPN, and ITGB1. This data provides initial insights into the pathophysiology of bone invasion in meningiomas and identifies factors that can be pursued as potential therapeutic targets.

Frequent ATRX mutations and loss of expression in adult diffuse astrocytic tumors carrying IDH1/IDH2 and TP53 mutations.

Gliomas are the most common primary brain tumors in children and adults. We recently identified frequent alterations in chromatin remodelling pathways including recurrent mutations in H3F3A and mutations in ATRX (α-thalassemia/mental-retardation-syndrome-X-linked) in pediatric and young adult glioblastoma (GBM, WHO grade IV astrocytoma). H3F3A mutations were specific to pediatric high-grade gliomas and identified in only 3.4 % of adult GBM. Using sequencing and/or immunohistochemical analyses, we investigated ATRX alterations (mutation/loss of expression) and their association with TP53 and IDH1 or IDH2 mutations in 140 adult WHO grade II, III and IV gliomas, 17 pediatric WHO grade II and III astrocytomas and 34 pilocytic astrocytomas. In adults, ATRX aberrations were detected in 33 % of grade II and 46 % of grade III gliomas, as well as in 80 % of secondary and 7 % of primary GBMs. They were absent in the 17 grade II and III astrocytomas in children, and the 34 pilocytic astrocytomas. ATRX alterations closely overlapped with mutations in IDH1/2 (p < 0.0001) and TP53 (p < 0.0001) in samples across all WHO grades. They were prevalent in astrocytomas and oligoastrocytomas, but were absent in oligodendrogliomas (p < 0.0001). No significant association of ATRX mutation/loss of expression and alternative lengthening of telomeres was identified in our cohort. In summary, our data show that ATRX alterations are frequent in adult diffuse gliomas and are specific to astrocytic tumors carrying IDH1/2 and TP53 mutations. Combined alteration of these genes may contribute to drive the neoplastic growth in a major subset of diffuse astrocytomas in adults.

Benefit of 5 years of enzyme replacement therapy in advanced late onset Pompe. A case report of misdiagnosis for three decades with acute respiratory failure at presentation.

We report on a 57 year old female patient who presented in acute respiratory failure with severe generalized weakness. She was previously misdiagnosed for over three decades as polymyositis. She was treated with enzyme replacement therapy (ERT) for over five years, after being diagnosed with late onset Pompe Disease (LOPD). She returned to independent living with the use of non invasive ventilation at nights. ERT should be considered in the management of patients with advanced LOPD and the effects of ERT closely monitored.

Endoscopic Coregistered Ultrasound Imaging and Precision Histotripsy: Initial In Vivo Evaluation.

Objective. Initial performance evaluation of a system for simultaneous high-resolution ultrasound imaging and focused mechanical submillimeter histotripsy ablation in rat brains. Impact Statement. This study used a novel combination of high-resolution imaging and histotripsy in an endoscopic form. This would provide neurosurgeons with unprecedented accuracy in targeting and executing nonthermal ablations in minimally invasive surgeries. Introduction. Histotripsy is a safe and effective nonthermal focused ablation technique. However, neurosurgical applications, such as brain tumor ablation, are difficult due to the presence of the skull. Current devices are too large to use in the minimally invasive approaches surgeons prefer. We have developed a combined imaging and histotripsy endoscope to provide neurosurgeons with a new tool for this application. Methods. The histotripsy component had a 10 mm diameter, operating at 6.3 MHz. Affixed within a cutout hole in its center was a 30 MHz ultrasound imaging array. This coregistered pair was used to ablate brain tissue of anesthetized rats while imaging. Histological sections were examined, and qualitative descriptions of ablations and basic shape descriptive statistics were generated. Results. Complete ablations with submillimeter area were produced in seconds, including with a moving device. Ablation progress could be monitored in real time using power Doppler imaging, and B-mode was effective for monitoring post-ablation bleeding. Collateral damage was minimal, with a 100 µm maximum distance of cellular damage from the ablation margin. Conclusion. The results demonstrate a promising hardware suite to enable precision ablations in endoscopic procedures or fundamental preclinical research in histotripsy, neuroscience, and cancer.

Pathology and genetics of meningiomas.

This article constitutes a mini-review of the pathology and genetics of meningiomas. Meningiomas are the most common primary intracranial tumors. They are usually durally based and are often found adjacent to venous sinuses and dural infoldings. The majority of these tumors are WHO grade I, although a minority is WHO grade II, atypical, or WHO grade III, anaplastic. Grade II and III meningiomas show a greater tendency than Grade I tumors to recur and metastasize. The current WHO scheme recognizes 15 histologic subtypes of meningiomas. Nine of these are WHO grade I, three are grade II, and three are grade III. In addition to these histologic subtypes, meningiomas can also be graded on the basis of mitotic activity, evidence of brain invasion, growth pattern cellular density, nuclear atypia, and necrosis. Loss of the long arm of chromosome 22, which is usually associated with inactivation of the NF2 gene, is the most common genetic abnormality found in meningiomas. Other chromosomal abnormalities associated with tumorogenesis and increased gradeof meningiomas include loss of heterozygosity for chromosome 1p, loss of 14q, deletion of 9p21, abnormalities of chromosome 10 and 17q. Telomerase activity increases with meningiomas grade as well. The only proven environmental risk factor for meningiomas is ionizing radiation. Radiation-induced meningiomas are more often multiple and have higher recurrence rates than standard meningiomas.

Mouse models of medulloblastoma.

Medulloblastoma is the most common malignant pediatric brain tumor. Despite its prevalence and importance in pediatric neuro-oncology, the genes and pathways responsible for its initiation, maintenance, and progression remain poorly understood. Genetically engineered mouse models are an essential tool for uncovering the molecular and cellular basis of human diseases, including cancer, and serve a valuable role as preclinical models for testing targeted therapies. In this review, we summarize how such models have been successfully applied to the study of medulloblastoma over the past decade and what we might expect in the coming years.

Germinoma of the Corpus Callosum.

A case is described of a young man presenting with diabetes insipidus and a junctional scotoma. A diffuse infiltrating mass centred in the corpus callosum and suprasellar area is found, which on pathological examination proved to be a primary intracranial germinoma. The case illustrates that rarely the corpus callosum can be involved by this tumour and that diagnosis may be delayed in atypical presentations.