The identification of a Distinct Astrocyte Subtype that Diminishes in Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the presence of two hallmark pathologies: the accumulation of Amyloid beta (Aβ) and tau proteins in the brain. There is a growing body of evidence suggesting that astrocytes, a type of glial cell in the brain, play crucial roles in clearing Aβ and binding to tau proteins. However, due to the heterogeneity of astrocytes, the specific roles of different astrocyte subpopulations in response to Aβ and tau remain unclear. To enhance the understanding of astrocyte subpopulations in AD, we investigated astrocyte lineage cells based on single-nuclei transcriptomic data obtained from both human and mouse samples. We characterized the diversity of astrocytes and identified global and subpopulation-specific transcriptomic changes between control and AD samples. Our findings revealed the existence of a specific astrocyte subpopulation marked by low levels of GFAP and the presence of AQP4 and CD63 expression, which showed functional enrichment in Aβ clearance and tau protein binding, and diminished in AD. We verified this type of astrocytes in mouse models and in AD patient brain samples. Furthermore, our research also unveiled significant alterations of the ligand-receptor interactions between astrocytes and other cell types. These changes underscore the complex interplay between astrocytes and neighboring cells in the context of AD. Overall, our work gives insights into astrocyte heterogeneity in the context of AD and reveals a distinct astrocyte subpopulation that holds potential for therapeutic interventions in AD. Targeting specific astrocyte subpopulations may offer new avenues for the development of novel treatments for AD.

Post-zygotic rescue of meiotic errors causes brain mosaicism and focal epilepsy

Somatic mosaicism is a known cause of neurological disorders, including developmental brain malformations and epilepsy. Brain mosaicism is traditionally attributed to post-zygotic genetic alterations arising in fetal development. Here we describe post-zygotic rescue of meiotic errors as an alternate origin of brain mosaicism in patients with focal epilepsy who have mosaic chromosome 1q copy number gains. Genomic analysis showed evidence of an extra parentally derived chromosome 1q allele in the resected brain tissue from five of six patients. This copy number gain is observed only in patient brain tissue, but not in blood or buccal cells, and is strongly enriched in astrocytes. Astrocytes carrying chromosome 1q gains exhibit distinct gene expression signatures and hyaline inclusions, supporting a novel genetic association for astrocytic inclusions in epilepsy. Further, these data demonstrate an alternate mechanism of brain chromosomal mosaicism, with parentally derived copy number gain isolated to brain, reflecting rescue in other tissues during development.

Novel Adjuvant Targeted Approach for PTEN-Mutated Choroid Plexus Carcinoma in Adults: Case Report and Literature Review

53-year-old female, with CPC and PTEN mutation by NGS, was successfully treated with everolimus and brain radiation

Fatal Hemophagocytic Lymphohistiocytosis Resulting in the Death of a Previously Healthy 49-Year-Old Man in Ten Days

Hemophagocytic lymphohistiocytosis (HLH) is an aggressive, life-threatening condition with sudden onset of a systemic inflammatory response syndrome. The triggers can be apparently non-specific, and the clinical presentations can be very deceptive during a rapidly deteriorating clinical course. Herein, we report a case of a 49-year-old White/Caucasian male with no known past medical history who presented with multi-organ failure, including liver, kidney, and bone marrow, along with disseminated intravascular coagulation. He had a high probability of HLH. Unfortunately, he died ten days after the initial presentation. At autopsy, the liver was necrotic and immunostains revealed diffuse positivity for HSV-1 & 2. The bone marrow was markedly hypocellular with phagocytes containing intact and fragmented red blood cells. There was also disseminated fungal infection involving almost all tissues. PCR, done on frozen tissue samples, revealed Aspergillus fumigatus. The rapid and fatal course of this patient illustrates the sometimes-aggressive course of HLH and the importance of autopsy examination in revealing the underlying etiology for this patient's death.

Complex I inhibitor of oxidative phosphorylation in advanced solid tumors and acute myeloid leukemia: phase I trials

Although targeting oxidative phosphorylation (OXPHOS) is a rational anticancer strategy, clinical benefit with OXPHOS inhibitors has yet to be achieved. Here we advanced IACS-010759, a highly potent and selective small-molecule complex I inhibitor, into two dose-escalation phase I trials in patients with relapsed/refractory acute myeloid leukemia (NCT02882321, n = 17) and advanced solid tumors (NCT03291938, n = 23). The primary endpoints were safety, tolerability, maximum tolerated dose and recommended phase 2 dose (RP2D) of IACS-010759. The PK, PD, and preliminary antitumor activities of IACS-010759 in patients were also evaluated as secondary endpoints in both clinical trials. IACS-010759 had a narrow therapeutic index with emergent dose-limiting toxicities, including elevated blood lactate and neurotoxicity, which obstructed efforts to maintain target exposure. Consequently no RP2D was established, only modest target inhibition and limited antitumor activity were observed at tolerated doses, and both trials were discontinued. Reverse translational studies in mice demonstrated that IACS-010759 induced behavioral and physiological changes indicative of peripheral neuropathy, which were minimized with the coadministration of a histone deacetylase 6 inhibitor. Additional studies are needed to elucidate the association between OXPHOS inhibition and neurotoxicity, and caution is warranted in the continued development of complex I inhibitors as antitumor agents.

Postmortem study of organ-specific toxicity in glioblastoma patients treated with a combination of temozolomide, irinotecan and bevacizumab

PURPOSE

Systemic chemotherapy including monotherapy with temozolomide (TMZ) or bevacizumab (BEV); two-drug combinations, such as irinotecan (IRI) and BEV, TMZ and BEV and a three-drug combination with TMZ, IRI and BEV (TIB) have been used in treating patients with progressive high-grade gliomas including glioblastoma (GBM). Most patients tolerated these regimens well with known side effects of hypertension, proteinuria, and reversible clinical myelosuppression (CM). However, organ- or system- specific toxicities from chemotherapy agents have never been examined by postmortem study. This is the largest cohort used to address this issue in glioma patients.

METHODS

Postmortem tissues (from all major systems and organs) were prospectively collected and examined by standard institution autopsy and neuropathological procedures from 76 subjects, including gliomas (N = 68, 44/M, and 24/F) and brain metastases (N = 8, 5/M, and 3/F) between 2009 and 2019. Standard hematoxylin and eosin (H&E) were performed on all major organs including brain specimens. Electronic microscopic (EM) study was carried out on 14 selected subject's kidney samples per standard EM protocol. Medical records were reviewed with adverse events (AEs) analyzed and graded according to the Common Terminology Criteria for Adverse Events (CTCAE), version 4.03. A swimmer plot was utilized to visualize the timelines of patient history by treatment group. The binary logistic regression models were performed to explore any associations between treatment strategies and incident myelosuppression.

RESULTS

Twenty-four glioma subjects were treated with TIB [median: 5.5 (range: 1-25) cycles] at tumor recurrence. Exposure to IRI significantly increased the frequency of CM (p = 0.05). No unexpected adverse events clinically, or permanent end-organ damage during postmortem examination was identified in glioma subjects who had received standard or prolonged duration of BEV, TMZ or TIB regimen-based chemotherapies except rare events of bone marrow suppression. The most common causes of death (COD) were tumor progression (63.2%, N = 43) followed by aspiration pneumonia (48.5%, N = 33) in glioma subjects. No COD was attributed to acute toxicity from TIB. The study also demonstrated that postmortem kidney specimen is unsuitable for studying renal ultrastructural pathological changes due to autolysis.

CONCLUSION

There is no organ or system toxicity by postmortem examinations among glioma subjects who received BEV, TMZ or TIB regimen-based chemotherapies regardless of durations except for occasional bone marrow suppression and reversible myelosuppression clinically. IRI, but not the extended use of TMZ, significantly increased CM in recurrent glioma patients. COD most commonly resulted from glioma tumor progression with infiltration to brain stem and aspiration pneumonia.

Somatic variants in diverse genes leads to a spectrum of focal cortical malformations

Post-zygotically acquired genetic variants, or somatic variants, that arise during cortical development have emerged as important causes of focal epilepsies, particularly those due to malformations of cortical development. Pathogenic somatic variants have been identified in many genes within the PI3K-AKT-mTOR-signalling pathway in individuals with hemimegalencephaly and focal cortical dysplasia (type II), and more recently in SLC35A2 in individuals with focal cortical dysplasia (type I) or non-dysplastic epileptic cortex. Given the expanding role of somatic variants across different brain malformations, we sought to delineate the landscape of somatic variants in a large cohort of patients who underwent epilepsy surgery with hemimegalencephaly or focal cortical dysplasia. We evaluated samples from 123 children with hemimegalencephaly (n = 16), focal cortical dysplasia type I and related phenotypes (n = 48), focal cortical dysplasia type II (n = 44), or focal cortical dysplasia type III (n = 15). We performed high-depth exome sequencing in brain tissue-derived DNA from each case and identified somatic single nucleotide, indel and large copy number variants. In 75% of individuals with hemimegalencephaly and 29% with focal cortical dysplasia type II, we identified pathogenic variants in PI3K-AKT-mTOR pathway genes. Four of 48 cases with focal cortical dysplasia type I (8%) had a likely pathogenic variant in SLC35A2. While no other gene had multiple disease-causing somatic variants across the focal cortical dysplasia type I cohort, four individuals in this group had a single pathogenic or likely pathogenic somatic variant in CASK, KRAS, NF1 and NIPBL, genes previously associated with neurodevelopmental disorders. No rare pathogenic or likely pathogenic somatic variants in any neurological disease genes like those identified in the focal cortical dysplasia type I cohort were found in 63 neurologically normal controls (P = 0.017), suggesting a role for these novel variants. We also identified a somatic loss-of-function variant in the known epilepsy gene, PCDH19, present in a small number of alleles in the dysplastic tissue from a female patient with focal cortical dysplasia IIIa with hippocampal sclerosis. In contrast to focal cortical dysplasia type II, neither focal cortical dysplasia type I nor III had somatic variants in genes that converge on a unifying biological pathway, suggesting greater genetic heterogeneity compared to type II. Importantly, we demonstrate that focal cortical dysplasia types I, II and III are associated with somatic gene variants across a broad range of genes, many associated with epilepsy in clinical syndromes caused by germline variants, as well as including some not previously associated with radiographically evident cortical brain malformations.

Cyclin D1 expression in Rosai-Dorfman disease: A near constant finding that is not invariably associated with MAPK/ERK pathway activation

Activating mutations in the MAPK/ERK pathway have been shown in nearly half of cases of Rosai-Dorfman disease (RDD). Cyclin D1, a key cell cycle regulator, constitutes a major downstream target of the MAPK/ERK pathway. In this study, we aim to further understand the pathogenesis of RDD by assessing the lesional histiocytes for cyclin D1, p-ERK, Ki-67 and BCL2 by immunohistochemistry We assessed 35 samples of RDD and a control group of histiocyte-rich reactive lesions. Cyclin D1 was expressed in about 90% of cases of RDD. Cyclin D1 was positive in 25-95% (median, 85%) of lesional histiocytes, was moderately/strongly expressed in 97% of cyclin D1-positive cases, and was significantly higher than in control specimens. p-ERK was positive in 16 of 30 (53%) cases of RDD and was negative in all controls. Whereas all p-ERK-positive RDD cases had concurrent cyclin D1 expression, over a third of cyclin D1-positive cases were negative for p-ERK. Ki-67 was low in RDD (median, 3%). BCL-2 was positive in lesional histiocytes in nine of 10 RDD cases assessed and was negative Overall, these findings point to unexpected, potential roles of these molecules in the pathogenesis of RDD. Overexpression of cyclin D1 in the absence of ERK phosphorylation in a subset of RDD cases opens the possibility of oncogenic mechanisms bypassing ERK, and supports the notion that cyclin D1 overexpression in RDD is multifactorial. Moreover, the observed lack of correlation between cyclin D1 with Ki-67 proliferative index suggests that prosurvival actions of cyclin D1 are, at least in part, cell-cycle independent. Finally, expression of BCL-2 and the low Ki-67 index suggest that RDD might be driven by anti-apoptotic rather than pro-proliferative oncogenic mechanisms.

Impacts of genotypic variants on survival following reoperation for recurrent glioblastoma

INTRODUCTION

Recurrent glioblastoma (rGBM) prognosis is dismal. In the absence of effective adjuvant treatments for rGBM, re-resections remain prominent in our arsenal. This study evaluates the impact of reoperation on post-progression survival (PPS) considering rGBM genetic makeup.

METHODS

To assess the genetic heterogeneity and treatment-related changes (TRC) roles in re-operated or medically managed rGBMs, we compiled demographic, clinical, histopathological, and next-generation genetic sequencing (NGS) characteristics of these tumors from 01/2005 to 10/2019. Survival data and reoperation were analyzed using conventional and random survival forest analysis (RSF).

RESULTS

Patients harboring CDKN2A/B loss (p = 0.017) and KDR mutations (p = 0.031) had notably shorter survival. Reoperation or bevacizumab were associated with longer PPS (11.2 vs. 7.4-months, p = 0.006; 13.1 vs 6.2, p < 0.001). Reoperated patients were younger, had better performance status and greater initial resection. In 136/273 (49%) rGBMs undergoing re-operation, CDKN2A/B loss (p = 0.03) and KDR mutations (p = 0.02) were associated with shorter survival. In IDH-WT rGBMs with NGS data (n = 166), reoperation resulted in 7.0-month longer survival (p = 0.004) than those managed medically. This reoperation benefit was independently identified by RSF analysis. Stratification analysis revealed that EGFR-mutant, CDKN2A/B-mutant, NF1-WT, and TP53-WT rGBM IDH-WT subgroups benefit most from reoperation (p = 0.03). Lastly, whether or not TRC was prominent at re-operation does not have any significant impact on PPS (10.5 vs. 11.5-months, p = 0.77).

CONCLUSIONS

Maximal safe re-resection significantly lengthens PPS regardless of genetic makeup, but reoperations are especially beneficial for IDH-WT rGBMs with EGFR and CDKN2A/B mutations with TP53-WT, and NF1-WT. Histopathology at recurrence may be an imperfect gauge of disease severity at progression and the imaging progression may be more reflective of the prognosis.

Molecular Alterations in Meningioangiomatosis Causing Epilepsy

Meningioangiomatosis (MA) is a rare process at the intersection of cerebral developmental and neoplastic disorders that often results in epilepsy. We evaluated molecular alterations in MA to characterize its biology and pathogenesis. We searched a comprehensive institutional database for patients with MA treated between 2004 and 2019. Demographic, clinical, surgical, and radiographical data were collected. MA and associated meningioma tissues were evaluated using a next-generation sequencing assay interrogating 1425 cancer-related genes. We studied 5 cases: 3 with MA and 2 with MA associated with a meningioma. Of the MAs associated with a meningioma, 1 had deletions in the NF2 gene in both the MA and the meningioma components, whereas the other had an NF2 deletion in only the MA component. Additional mutations were identified in the MA components, suggesting that MA arises from the meningioma rather than the meningioma resulting from a transformation of the MA. The 3 cases of pure MA showed variants of unknown significance with no alterations in known oncogenic drivers. Our findings provide a starting point to a better understanding of the pathogenesis of this rare lesion. Our study indicates that MA-meningiomas have a neoplastic nature that differs from the hamartomatous/developmental nature of pure MA.

A Postmortem Portrait of the Coronavirus Disease 2019 (COVID-19) Pandemic: A Large Multi-institutional Autopsy Survey Study

CONTEXT.—

This study represents the largest compilation to date of clinical and postmortem data from decedents with coronavirus disease 2019 (COVID-19). It will augment previously published small series of autopsy case reports, refine clinicopathologic considerations, and improve the accuracy of future vital statistical reporting.

OBJECTIVE.—

To accurately reflect the preexisting diseases and pathologic conditions of decedents with SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection through autopsy.

DESIGN.—

Comprehensive data from 135 autopsy evaluations of COVID-19-positive decedents is presented, including histologic assessment. Postmortem examinations were performed by 36 pathologists at 19 medical centers or forensic institutions in the United States and Brazil. Data from each autopsy were collected through the online submission of multiple-choice and open-ended survey responses.

RESULTS.—

Patients dying of or with COVID-19 had an average of 8.89 pathologic conditions documented at autopsy, spanning a combination of prior chronic disease and acute conditions acquired during hospitalization. Virtually all decedents were cited as having more than 1 preexisting condition, encompassing an average of 2.88 such diseases each. Clinical conditions during terminal hospitalization were cited 395 times for the 135 autopsied decedents and predominantly encompassed acute failure of multiple organ systems and/or impaired coagulation. Myocarditis was rarely cited.

CONCLUSIONS.—

Cause-of-death statements in both autopsy reports and death certificates may not encompass the severity or spectrum of comorbid conditions in those dying of or with COVID-19. If supported by additional research, this finding may have implications for public health decisions and reporting moving forward through the pandemic.

Hemorrhagic Giant Cell Tumor of the Occipital Skull Base: A Case Report and Literature Review

Giant cell tumor of bone is a benign but locally aggressive osteolytic neoplasm that represents 3% to 5% of all primary bone tumors, primarily found at the epiphyses of long bones. Less than 1% are of calvarial origin. Herein, we report a rare case of a nine-year-old girl with a hemorrhagic giant cell tumor of the left occipital skull base.

Landscape of Genomic Alterations in IDH Wild-Type Glioblastoma Identifies PI3K as a Favorable Prognostic Factor

PURPOSE

IDH wild-type (WT) glioblastoma (GBM) is an aggressive tumor with poor survival despite current therapies. The aim of this study was to characterize its genomic profile and determine whether a particular molecular signature is associated with improved survival outcomes.

PATIENTS AND METHODS

Tumor samples from 232 patients with IDH-WT GBM were sequenced, and the landscape of genomic alterations was fully delineated. Genomics data from The Cancer Genome Atlas (TCGA) cohort were analyzed for confirmation. Association of alterations with survival was evaluated in both univariable and multivariable approaches.

RESULTS

The genomic landscape of IDH-WT GBM revealed a high frequency of CDKN2A/B loss, TERT promoter mutations, PTEN loss, EGFR alteration, and TP53 mutations. Novel variants or gene mutations, such as ARID1B and MLL2, were identified. To better understand synergistic effects and facilitate decision making for precision medicine, we identified 11 pairs of gene alterations that tended to co-occur or were mutually exclusive, which were confirmed in the TCGA cohort. Survival analysis showed that genomic alterations in TP53 were associated with worse overall survival (OS). However, alterations in PI3K class I genes were associated with significantly better OS (univariable analysis: P = .002; multivariable analysis: hazard ratio [HR], 0.5785; P = .00162) and longer progression-free survival (univariable analysis: P = .0043; multivariable analysis: HR, 0.6228; P = .00913).

CONCLUSION

Genomic alterations in PI3K class I are a favorable prognostic factor in IDH-WT GBM. This new prognostic biomarker may facilitate risk stratification of patients, assist in clinical trial enrollment, and provide potential therapeutic targets

The Variable Appearance of Third Ventricular Colloid Cysts: Correlation with Histopathology and the Risk of Obstructive Ventriculomegaly

BACKGROUND AND PURPOSE

While third ventricular colloid cysts may present as an incidental finding, they also harbor the potential to cause ventricular obstruction and sudden death. Herein we analyze the relationship between imaging appearance and the risk of obstructive ventriculomegaly.

MATERIALS AND METHODS

This is a retrospective review of the MR imaging appearance of 64 patients with colloid cysts, 46 of whom also had a CT scan, obtained by a tertiary hospital imaging report data base search over a 10-year period. Cysts were categorized by appearance on T2-FLAIR and correlated with patient age, cyst size, and the risk of obstructive ventriculomegaly. Histopathologic correlation was available for 28 cases.

RESULTS

The 64-patient cohort was 52% female, median age 50 years (range 10 to 99 years). Cysts hyperintense on T2-FLAIR (53.1%) were larger (P <.001), occurred in younger patients (P = .01), and had a higher risk of obstructive ventriculomegaly than homogeneously hypointense cysts (relative risk 6.18, 95% CI [2.04, 18.67]). Three patterns of T2 hyperintensity were identified: homogeneously hyperintense, hyperintense rim, and cysts with "dot sign." Although "dot sign" cysts were larger (P < .001), there was no significant difference in patient age or the risk of ventricular obstruction among T2 hyperintense cysts. Cyst wall histopathology did not vary with imaging appearance.

CONCLUSIONS

Hyperintensity on T2-FLAIR, whether homogeneous, rim, or "dot sign," is associated with larger cyst size and younger patient age, and is an imaging risk factor for obstructive ventriculomegaly. The hyperintense rim does not represent a thickened cyst wall.

Additional genetic alterations in BRAF-mutant gliomas correlate with histologic diagnoses

INTRODUCTION

Recently, the term "Diffuse glioma, BRAF V600E-mutant" has been recommended for IDH-wildtype gliomas with BRAF p.V600E mutation and without CDKN2A/B deletion. However, additional alterations in gliomas that coexist with BRAF-mutations are poorly defined.

METHODS

We analyzed next-generation sequencing results in 315 cancer-associated genes for 372 gliomas from our institution (2010 to 2017). In addition, we reviewed IDH-WT gliomas with mutation and copy-number alterations available in cBioPortal, to further characterize BRAF-mutant gliomas.

RESULTS

Seventeen (4.6%) showed BRAF mutations. Tumor types included 8 glioblastomas, 2 epithelioid glioblastomas (E-GBM), 2 pleomorphic xanthoastrocytomas (PXA), 1 anaplastic oligodendroglioma, 1 diffuse astrocytoma, and 3 pilocytic astrocytomas. Fifty-three percent (53%) of cases exhibited BRAF-alterations other than p.V600E. The majority of the tumors were localized in the temporal lobe (52.9%). In addition to BRAF mutations, glioblastomas showed concomitant mutations in TP53 (3/8), CDKN2A/B-loss (6/8), TERT-promoter (6/8), and/or PTEN (5/8). Both E-GBMs and PXAs showed CDKN2A/B-loss and BRAF p.V600E with absence of TERTp, TP53, and PTEN mutations. Similar findings were observed in BRAF-mutant infiltrating gliomas from cBioPortal.

CONCLUSIONS

Knowledge of additional alterations that co-occur with BRAF-mutations in gliomas may improve diagnosis and help identify patients that could benefit from targeted therapies. Furthermore, we provide examples of two patients whose tumors responded to BRAF pathway inhibitors, arguing in favor of these therapies in patients with BRAF-mutant gliomas.

Full Remission of Long-Term Premenstrual Dysphoric Disorder-Like Symptoms Following Resection of a Pituitary Adenoma: Case Report

Patient: Female, 44-year-old

Final Diagnosis: Pituitary adenoma

Symptoms: Depression and anxiety

Medication:—

Clinical Procedure: —

Specialty: Neurosurgery • Psychiatry

Filamin A-negative hyaline astrocytic inclusions in pediatric patients with intractable epilepsy: report of 2 cases

Although rare, hyaline cytoplasmic inclusions isolated to astrocytes of the cerebral cortex have been identified in a spectrum of diseases ranging from intractable epilepsy in pediatric patients with only mild to moderate developmental delays to Aicardi syndrome. These inclusions classically stain positive for filamin A, giving rise to the term "filaminopathies." The authors report on 2 pediatric patients with intractable epilepsy and developmental delay who uniquely displayed filamin A-negative hyaline astrocytic inclusions in resected brain tissues. Additionally, these inclusions stained positive for S100 and negative for glial fibrillary acidic protein, chromogranin, neurofilament, CD34, vimentin, periodic acid-Schiff (PAS), and Alcian blue. These are the first reported cases of filamin A-negative hyaline astrocytic inclusions, providing a novel variation on a previously reported entity and justification to further investigate the pathogenesis of these inclusions. The authors compare their findings with previously reported cases and review the literature on hyaline astrocytic inclusions in intractable pediatric epilepsy.

Dysregulated Gut Homeostasis Observed Prior to the Accumulation of the Brain Amyloid-β in Tg2576 Mice

Amyloid plaques in Alzheimer's disease (AD) are associated with inflammation. Recent studies demonstrated the involvement of the gut in cerebral amyloid-beta (Aβ) pathogenesis; however, the mechanisms are still not well understood. We hypothesize that the gut bears the Aβ burden prior to brain, highlighting gut-brain axis (GBA) interaction in neurodegenerative disorders. We used pre-symptomatic (6-months) and symptomatic (15-months) Tg2576 mouse model of AD compared to their age-matched littermate WT control. We identified that dysfunction of intestinal epithelial barrier (IEB), dysregulation of absorption, and vascular Aβ deposition in the IEB occur before cerebral Aβ aggregation is detectible. These changes in the GBA were associated with elevated inflammatory plasma cytokines including IL-9, VEGF and IP-10. In association with reduced cerebral myelin tight junction proteins, we identified reduced levels of systemic vitamin B12 and decrease cubilin, an intestinal B12 transporter, after the development of cerebral Aβ pathology. Lastly, we report Aβ deposition in the intestinal autopsy from AD patients with confirmed cerebral Aβ pathology that is not present in intestine from non-AD controls. Our data provide evidence that gut dysfunction occurs in AD and may contribute to its etiology. Future therapeutic strategies to reverse AD pathology may involve the early manipulation of gut physiology and its microbiota.

Posttreatment Maturation of Medulloblastoma into Gangliocytoma: Report of 2 Cases

INTRODUCTION

We report 2 cases of medulloblastoma maturing into gangliocytoma after receiving multimodal therapy. Here we present 2 cases of diagnosed medulloblastoma which on re-resection were noted to be gangliocytoma without heterogeneity, which is an extremely rare occurrence.

CASE PRESENTATION

The first patient, an 11-year-old boy diagnosed with high-risk (non-WNT, non-SHH) medulloblastoma, was treated with near-total surgical resection followed by craniospinal radiation therapy with weekly vincristine. He then received maintenance chemotherapy with vincristine, cyclophosphamide, and cisplatin. On surveillance MR imaging studies residual tumor in the lateral aspect of the tumor bed was noted to be slowly growing, eliciting gross-total resection of the residual tumor. Histopathology showed benign gangliocytoma without residual medulloblastoma. The second patient, a 3-year-old girl, was diagnosed with medulloblastoma, desmoplastic nodular variant. She was initially treated with gross total resection and chemotherapy with etoposide, carboplatin, and high-dose methotrexate. At 4 months off therapy, she was noted to have local recurrence along the resection cavity. Second-line therapy was started with irinotecan and temozolomide, but MRI assessment during treatment showed further disease progression. She then received craniospinal radiation. Eleven months off therapy, further radiographic progression was noted, and the patient underwent second-look surgery, with pathology showing gangliocytoma and treatment-related gliosis.

DISCUSSION/CONCLUSION

The maturation of medulloblastoma into a ganglion cell-rich lesion is very rare, with few well-characterized previous reports. Given the rare nature of this entity, it would be of great value to understand the process of posttreatment maturation and the genetic and treatment factors which contribute to this phenomenon.

Lactobacillus reuteri reduces the severity of experimental autoimmune encephalomyelitis in mice by modulating gut microbiota

The gut microbiome plays an important role in immune function and has been implicated in multiple sclerosis (MS). However, how to modulate microbiota to prevent or treat MS remain largely unknown. Probiotic Lactobacillus reuteri DSM 17938 (L. reuteri) has anti-inflammatory effects in mouse models of neonatal necrotizing enterocolitis and Treg-deficiency-induced autoimmune disease. L. reuteri in these models modulated gut microbiota and microbiota-associated metabolites to inhibit TH1 and TH2 differentiation and their-associated cytokines, significantly ameliorating the severity of these diseases. An in vitro study indicated that L. reuteri inhibits the differentiation of naïve CD4+T cells into TH17 and TH1 cells. We determined the effect of L. reuteri on experimental autoimmune encephalomyelitis (EAE) mouse model, a widely used animal model of MS, a model which is primarily mediated by TH17 and TH1 cells. We discovered that L. reuteri treatment reduced TH1/TH17 cells and their associated cytokines IFN-γ/IL-17 in EAE, inhibiting the development of EAE. We also showed that the loss of diversity in gut microbiota induced by EAE was largely restored by L. reuteri treatment. Taxonomy-based analysis of gut microbiota showed that the “beneficial” genera Bifidobacterium, Prevotella, and Lactobacillus were negatively correlated with EAE clinical severity scores, whereas the genera Anaeroplasma, Rikenellaceae, and Clostridium were positively correlated. Notably, L. reuteri treatment altered the relative abundances of these EAE-associated taxa in mice. In conclusion, probiotic L. reuteri changed gut microbiota to modulate immune responses in EAE, making it a novel candidate in future studies to modify the severity of MS.

Lactobacillus reuteri Reduces the Severity of Experimental Autoimmune Encephalomyelitis in Mice by Modulating Gut Microbiota

The gut microbiome plays an important role in immune function and has been implicated in multiple sclerosis (MS). However, how and if the modulation of microbiota can prevent or treat MS remain largely unknown. In this study, we showed that probiotic Lactobacillus reuteri DSM 17938 (L. reuteri) ameliorated the development of murine experimental autoimmune encephalomyelitis (EAE), a widely used animal model of MS, a model which is primarily mediated by T_H17 and T_H1 cells. We discovered that L. reuteri treatment reduced T_H1/T_H17 cells and their associated cytokines IFN-γ/IL-17 in EAE mice. We also showed that the loss of diversity of gut microbiota induced by EAE was largely restored by L. reuteri treatment. Taxonomy-based analysis of gut microbiota showed that three “beneficial” genera Bifidobacterium, Prevotella, and Lactobacillus were negatively correlated with EAE clinical severity, whereas the genera Anaeroplasma, Rikenellaceae, and Clostridium were positively correlated with disease severity. Notably, L. reuteri treatment coordinately altered the relative abundance of these EAE-associated taxa. In conclusion, probiotic L. reuteri changed gut microbiota to modulate immune responses in EAE, making it a novel candidate in future studies to modify the severity of MS.

Triple-drug Therapy With Bevacizumab, Irinotecan, and Temozolomide Plus Tumor Treating Fields for Recurrent Glioblastoma: A Retrospective Study

Clinical studies treating pediatric and adult solid tumors, such as glioblastoma (GBM), with a triple-drug regimen of temozolomide (TMZ), bevacizumab (BEV), and irinotecan (IRI) [TBI] have demonstrated various efficacies, but with no unexpected toxicities. The TBI regimen has never been studied in recurrent GBM (rGBM) patients. In this retrospective study, we investigated the outcomes and side effects of rGBM patients who had received the TBI regimen. We identified 48 adult rGBM patients with a median age of 56 years (range: 26-76), who received Tumor Treating Fields (TTFields) treatment for 30 days or longer, and concurrent salvage chemotherapies. The patients were classified into two groups based on chemotherapies received: TBI with TTFields (TBI+T, N = 18) vs. bevacizumab (BEV)-based chemotherapies with TTFields (BBC+T, N = 30). BBC regimens were either BEV monotherapy, BEV+IRI or BEV+CCNU. Patients in TBI+T group received on average 19 cycles of TMZ, 26 and 21 times infusions with BEV and IRI, respectively. Median overall survival (OS) and progression-free survival (PFS) for rGBM (OS-R and PFS-R) patients who received TBI+T were 18.9 and 10.7 months, respectively. In comparison, patients who received BBC+T treatment had OS-R and PFS-R of 11.8 (P > 0.05) and 4.7 (P < 0.05) months, respectively. Although the median PFS results were significantly different by 1.5 months (6.6 vs. 5.1) between TBI+T and BBC+T groups, the median OS difference of 14.7 months (32.5 vs. 17.8) was more pronounced, P < 0.05. Patients tolerated TBI+T or BBC+T treatments well and there were no unexpected toxicities. The most common side effects from TBI+T treatment included grade III hypertension (38.9%) and leukopenia (22.2%). In conclusion, the TBI regimen might play a role in the improvement of PFS-R and OS-R among rGBM patients. Prospective studies with a larger sample size are warranted to study the efficacy and toxicity of TBI+T regimen for rGBM.

Primary Central Nervous System Lymphoma with Associated Demyelination and Creutzfeldt Astrocytes

A previously healthy 54-year-old woman presented with weight loss, progressive weakness that was more pronounced on the left side, and intermittent occipital headaches. Imaging studies showed multiple enhancing lesions along the white matter, compatible with a demyelinating process. The patient's previous history included relapsing-remitting symptoms of weakness over the past 3 years. A stereotactic brain biopsy showed histological features of demyelination with an associated population of neoplastic lymphoid cells. These unusual findings raise the question of whether demyelinating disease preceded the development of primary CNS lymphoma (PCNSL), or whether PCNSL induced demyelination. Although rare, cases of "sentinel lesions" heralding the diagnosis of PCNSL have been reported. This case emphasizes the importance of having a high index of suspicion of PCNSL in the setting of suspected demyelinating lesion in an adult patient.

Cryopreserved human umbilical cord patch for in-utero spina bifida repair

OBJECTIVE

To identify a patch system to repair surgically created spina bifida in a sheep model for its efficacy in healing the skin defect, protecting the underlying spinal cord and reducing the Chiari II malformation.

METHODS

Spina bifida was created surgically in 16 fetuses from eight timed-pregnant sheep at gestational age of 75 days. Two fetuses did not survive the procedure. Repeat hysterotomy was performed at 95 days' gestation to cover the defect with either biocellulose film with underwater adhesive (BCF-adhesive) (n = 7) or human umbilical cord with suture (HUC-suture) (n = 7). Three fetuses without formation of the defect served as reference controls. The skin healing was examined by direct visualization after a planned Cesarean section at term, followed by histological analysis using hematoxylin and eosin and Masson's trichrome stains. Mid-sagittal sections of the fetal cranium and upper cervical spine were analyzed by a pediatric neuroradiologist who was blinded to the type of patch received.

RESULTS

Three fetuses that received the BCF-adhesive and six fetuses that received the HUC-suture survived to term for final analysis. As a result of dislodgment of the BCF-adhesive, all spina bifida defects repaired using BCF-adhesive were not healed and showed exposed spinal cord with leakage of cerebrospinal fluid. In contrast, all spinal defects repaired by HUC-suture were healed with complete regrowth of epidermal, dermal and subdermal tissue components, with no exposed spinal cord. The maximal skin wound width was 21 ± 3.6 mm in the BCF-adhesive group but 3 ± 0.8 mm in the HUC-suture group (P < 0.001). The spinal cord area (P = 0.001) and the number of anterior horn cells (P = 0.03) was preserved to a greater degree in the HUC-suture group than in the BCF-adhesive group, whilst psammoma bodies, signifying neuronal degeneration, were only observed in the BCF-adhesive group. Anatomic changes, indicative of Chiari II malformation, were seen in all three fetuses of the BCF-adhesive group but in none of the HUC-suture group (P < 0.01).

CONCLUSION

Cryopreserved umbilical cord graft is a promising regenerative patch for intrauterine repair of spina bifida.

Activation of extracellular regulated kinase and mechanistic target of rapamycin pathway in focal cortical dysplasia

Neuropathology of resected brain tissue has revealed an association of focal cortical dysplasia (FCD) with drug-resistant epilepsy (DRE). Recent studies have shown that the mechanistic target of rapamycin (mTOR) pathway is hyperactivated in FCD as evidenced by increased phosphorylation of the ribosomal protein S6 (S6) at serine 240/244 (S(240/244) ), a downstream target of mTOR. Moreover, extracellular regulated kinase (ERK) has been shown to phosphorylate S6 at serine 235/236 (S(235/236) ) and tuberous sclerosis complex 2 (TSC2) at serine 664 (S(664) ) leading to hyperactive mTOR signaling. We evaluated ERK phosphorylation of S6 and TSC2 in two types of FCD (FCD I and FCD II) as a candidate mechanism contributing to mTOR pathway dysregulation. Tissue samples from patients with tuberous sclerosis (TS) served as a positive control. Immunostaining for phospho-S6 (pS6(240/244) and pS6(235/236) ), phospho-ERK (pERK), and phospho-TSC2 (pTSC2) was performed on resected brain tissue with FCD and TS. We found increased pS6(240/244) and pS6(235/236) staining in FCD I, FCD II and TS compared to normal-appearing tissue, while pERK and pTSC2 staining was increased only in FCD IIb and TS tissue. Our results suggest that both the ERK and mTOR pathways are dysregulated in FCD and TS; however, the signaling alterations are different for FCD I as compared to FCD II and TS.

R54C Mutation of NOTCH3 Gene in the First Rungus Family with CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary stroke caused by mutations in NOTCH3 gene. We report the first case of CADASIL in an indigenous Rungus (Kadazan-Dusun) family in Kudat, Sabah, Malaysia confirmed by a R54C (c.160C>T, p.Arg54Cys) mutation in the NOTCH3. This mutation was previously reported in a Caucasian and two Korean cases of CADASIL. We recruited two generations of the affected Rungus family (n = 9) and found a missense mutation (c.160C>T) in exon 2 of NOTCH3 in three siblings. Two of the three siblings had severe white matter abnormalities in their brain MRI (Scheltens score 33 and 50 respectively), one of whom had a young stroke at the age of 38. The remaining sibling, however, did not show any clinical features of CADASIL and had only minimal changes in her brain MRI (Scheltens score 17). This further emphasized the phenotype variability among family members with the same mutation in CADASIL. This is the first reported family with CADASIL in Rungus subtribe of Kadazan-Dusun ethnicity with a known mutation at exon 2 of NOTCH3. The penetrance of this mutation was not complete during the course of this study.

Cerebellar pleomorphic xanthoastrocytoma in a patient with neurofibromatosis type 1: a case report and literature review

Pleomorphic xanthoastrocytoma (PXA) is an uncommon tumor of young adults that typically occurs supratentorially. It is generally considered to be a low-grade, circumscribed tumor that when treated by surgical resection has a relatively favorable outcome. Cases of cerebellar PXA are rare, and those associated with neurofibromatosis type 1 (NF1) are even less common, with only 2 cases reported to date. We present herein a third case of PXA-NF1 with unusual features. A 33-year-old woman presented with a history of headache. Her medical and family history was significant for NF1. Brain MRI revealed a 3.4 cm ill-defined lesion with a gyriform enhancing pattern in the left cerebellum, superficially mimicking Lhermitte-Duclos disease. The patient underwent a gross total resection of the lesion and had an unremarkable postoperative course. While the lesion had histological features typical of "pure" PXA (WHO grade II) it had an unusual growth pattern with thickening of the superficial cerebellar folia and predominant leptomeningeal involvement. No BRAF, IDH-1, or IDH-2 mutation was identified. Three months after surgery, local recurrence was detected, and the patient was treated with radiation therapy. One year after the first surgery, she underwent surgical resection of the recurrent/residual tumor. Histologically, the recurrent tumor showed very similar features to the initially resected tumor, with no anaplastic features. Most cerebellar PXAs have an indolent clinical behavior as do most cerebral PXAs. Whether co-existence of NF1 was a factor in altering the clinical course and biologic behavior of this patient's tumor is currently unknown.

Brain metastasis of crystal-deficient, CD68-positive alveolar soft part sarcoma: ultrastructural features and differential diagnosis

We report a case of alveolar soft part sarcoma (ASPS) presenting as an isolated frontal lobe metastasis. The tumor demonstrated little or no immunoreactivity for a broad panel of antibodies yet strong, diffuse immunoreactivity with CD68. On electron microscopy, the characteristic rectangular to rhomboid crystalline inclusions of ASPS were not present. Electron-dense granules resembling peroxisomes were present, sometimes in association with elongated granular structures having a periodic, lattice-like arrangement. Metastatic ASPS was confirmed by demonstration of an ASPSCR1-TFE3 fusion and imaging studies that excluded metastatic Xp11.2 translocation renal cell carcinoma. The primary site was subsequently identified in the lower extremity.

Encephalomalacic dysplastic mass lesion associated with vascular abnormalities in an elderly man. Is this "acquired" focal cortical dysplasia?

Focal cortical dysplasia (FCD) is known to occur in association with a principal lesion and has been newly introduced as FCD type III in the ILAE 2011 classification system of FCDs. FCD type IIIc is associated with vascular malformations, and in all such cases in the literature with histologic confirmation, the principal lesion was a cavernous angioma. We present here a case of mass-forming FCD type IIIc with very unusual vasculopathies. The patient, a 75-year-old man, presented with a seizure and left-sided weakness. MRI showed a right frontal intra-axial mass (4 cm in diameter). He had significant multiple cardiovascular risk factors and a history of melanoma and bladder cancer. Craniotomy was performed for excision of the suspected neoplasm. Histologically, the cortex showed transition from normal, laminar cortical architecture to marked architectural abnormality with irregular areas of encephalomalacia, with intervening, almost nodular regions of "preserved" cortex. These regions consisted of large clusters of dysplastic and maloriented neurons. There were medium-sized to larger arteries with marked medial thickening and luminal stenosis, predominantly within the markedly thickened and fibrosed leptomeninges. In addition, the parenchymal vessels showed markedly hyalinized and thickened walls, and several exhibited glomeruloid clusters of new capillaries. We interpreted the cortical and subcortical encephalomalacic features to be presumably "secondary" to the underlying/associated vascular pathology. This case may represent "acquired" FCD. It is possible that this patient had a preexistent cortical dysplasia with secondary ischemic changes; however, given the absence of previous history of seizure, this appears less likely.

Traumatic rupture of an intracranial dermoid cyst: Case report and literature review

BACKGROUND

Dermoid tumors are benign congenital cystic lesions that usually present with local mass effect. Very rarely, they present as spontaneous ruptures. Traumatic rupture of these dermoid cysts is an extremely rare event and only a handful of such cases have been ever reported.

CASE DESCRIPTION

A 47-year-old female presented to our hospital with a ruptured intracranial dermoid cyst following a mild head injury. The ruptured cyst contents were disseminated into the subarachnoid and intraventricular compartments, resulting in an obstructive hydrocephalus. After medical stabilization, she underwent gross total resection of the cyst using combined transsylvian, transcortical-transventricular, and sub-frontal approaches. A ventriculo-peritoneal shunt was eventually also needed.

CONCLUSION

Traumatic rupture of an intracranial dermoid cyst is an extremely rare event and this is only the fourth such case reported in the literature. We presume that this rupture occurs due to sudden shifts in the cyst sac, which is adherent to some partially mobile intracranial contents. Although computed tomography (CT) is often adequate in making a diagnosis of this entity, magnetic resonance imaging (MRI) provides complete characterization of the extent of lipid dissemination, and is essential for operative planning. Intravenous steroids at presentation are helpful in managing the aseptic meningitis associated with rupture. Complete surgical resection is the goal, but must be weighed against the risk for injury to nearby vital structures. Hydrocephalus should be managed promptly, and patients should be monitored for it closely in the perioperative period. Even though the recurrence rate with subtotal resection is extremely rare, follow up should be done routinely.

Neuropathology of Seizure Disorders

Epilepsy is a common neurological disorder characterized by an enduring predisposition to generate recurrent seizures. Pathologists may be called upon to evaluate brain tissue from patients with a history of seizures, and it is important to keep in mind the diversity of histopathologic findings associated with this disorder and the limitations imposed by both, limited sampling and neuroanatomy. Review of the literature has shown that the three most common clinicopathological entities in surgically resected medically refractory epilepsy are mesial temporal sclerosis (MTS), long-term epilepsy-associated tumors (LEAT), and malformations of cortical development (MCD) which includes focal cortical dysplasia (FCD). Here, we will review the most common clinicopathological entities seen in surgically resected cases of refractory epilepsy, such as MTS, MCD, LEAT, as well as vascular and encephalitic lesions. We will also touch upon traumatic brain injuries and SUDEP, and the role of the forensic pathologist. A better understanding of the etiopathology, recent classifications, and underlying molecular mechanisms involved in each entity will be helpful in order to identify the cause of death in patients with seizure disorders, candidates who will benefit from tailored surgical resection strategies, as well as to develop new and targeted drug treatment.

Neuron precursor features of spindle cell oncocytoma of adenohypophysis

CONTEXT

Spindle cell oncocytoma of the adenohypophysis (SCO) is a non-endocrine neoplasm with few recurrent forms described. It arises from the folliculo-stellate cells of the adenohypophysis.

OBJECTIVE

We describe a case of SCO in a 24-year-old woman and provide pathogenetic information.

DESIGN

Hematoxylin-eosin (H&E), and immunohistochemistry, with controls, for S100, SMI-311, neurofilament, EMA, CD68, GFAP, chromogranin, synaptophysin, and Ki67 were performed. CD44, nestin, Gli2, p-Akt(Ser 473) and p-mTOR(Ser 2448) antibodies were applied, and each analyte's cellular distribution and intensity were noted.

RESULTS

H&E showed a proliferation of spindle and polygonal cells with a fascicular pattern, without mitoses. There was reactivity for SMI-311, CD44, nestin, S100, EMA, and vimentin. Neurofilament, CD68, chromogranin, synaptophysin, and GFAP were not expressed. p-Akt and p-mTOR were expressed suggesting mTORC2. Gli2 showed nuclear expression in the tumoral cells.

CONCLUSIONS

These findings suggest that SCO has neuron-like precursor cells. Sonic hedgehog and mTOR pathways are activated.

Diffuse and uncontrolled vascular smooth muscle cell proliferation in rapidly progressing pediatric moyamoya disease

Moyamoya disease is a rare stroke syndrome of unknown etiology resulting from stenosis or occlusion of the supraclinoid internal carotid artery (ICA) in association with an abnormal vascular network in the basal ganglia. Although the highest incidence of moyamoya disease is in pediatric patients, pathology reports have been primarily limited to adult samples and describe occlusive fibrocellular lesions in the intimae of affected arteries. We describe the case of a young girl with primary moyamoya disease who presented at 18 months of age with right hemiparesis following an ischemic stroke. Angiography showed stenosis of the distal left ICA, left middle cerebral artery, and right ICA. An emergent left-sided dural inversion was performed. Recurrent strokes and alternating hemiplegia necessitated a right dural inversion 6 months later. Nonetheless, her aggressive disease proved uniquely refractory to surgical revascularization, and she succumbed to recurrent strokes and neurological deterioration at 2.5 years of age. Pathological specimens revealed a striking bilateral occlusion of the anterior carotid circulation resulting from intimal proliferation of smooth muscle cells (SMCs). Most strikingly, the ascending aorta and the superior mesenteric artery demonstrated similar intimal proliferation, along with SMC proliferation in the media. The systemic pathology involving multiple arteries in this extremely young child, the first case of its kind available for autopsy, suggests that globally uncontrolled SMC proliferation, in the absence of environmental risk factors and likely resulting from an underlying genetic alteration, may be a primary etiologic event leading to moyamoya disease.

Dual pathology in Rasmussen's encephalitis: a study of seven cases and review of the literature

Dual pathology has previously been reported in less than 10% of cases of Rasmussen's encephalitis (RE). Given the rarity of RE, it appears unlikely that dual pathology in RE is merely a coincidence. We therefore reviewed all cases of RE experienced in our institution to assess for an additional/associated pathology. A total of seven patients with RE were identified in our archives. Seven children (4 boys and 3 girls, age range: 3-16 years, mean: 9.5 years) with medically refractory epilepsy underwent surgical resection for intractable seizures. The surgical specimens were examined with routine neurohistological techniques, and immunohistochemistry was performed with an extensive panel of antibodies for viruses, lymphocytes, microglia/macrophages, human leukocyte antigen (HLA)-DR, astrocytes, and neurons. Relevant literature was reviewed. Microscopically, all seven cases demonstrated the inflammatory pathology of RE in the cortex and white matter with leptomeningeal and perivascular lymphocytic infiltration, microglial nodules with/without neuronophagia, neuronal loss and gliosis. The HLA-DR antibody was extremely helpful in highlighting the extent of microglial cell proliferation/activation that was not appreciable with standard histology. An unexpected finding in all seven cases was the presence of cortical dysplasia. In our series of seven cases, there was co-occurrence of the inflammatory/destructive pathology of RE with malformative/dysplastic features in cortical architecture in 100% of cases, raising questions about the possible relationships between the two entities. Awareness of the possibility of dual pathology in RE is important for clinical and pathological diagnosis, and may affect the management and outcome of these patients. Immunohistochemistry is very helpful to make a definitive diagnosis of both pathologies.

Mitochondrial Disorder, Diabetes Mellitus, and Findings in Three Muscles, Including the Heart

The authors describe the case of a 50-year-old man with chronic progressive external ophthalmoplegia (CPEO), diabetes mellitus (DM), and coronary artery disease. The patient had no cardiac conduction abnormalities. During coronary artery bypass surgery, his heart and two skeletal muscles were biopsied. All three muscles showed ragged red fibers. The heart muscle showed significant glycogen accumulation. Analysis of mitochondrial DNA (mtDNA) showed a 5019-base-pair deletion, with no duplications. There were morphologically abnormal mitochondria in all 3 muscles, with clinically apparent difference in preservation of function. The combination of diabetes mellitus and mtDNA deletion is fortuitous, as they can be causally linked. The cardiac pathology allows speculation about the possible adaptive processes that may occur in the heart in DM. There are few reported cases with CPEO and excess glycogen in the heart. Most show deposition of fat and poorer clinical outcomes as compared to those with glycogen deposition. This observation may lend support to the hypothesis that in the myocardium, adaptive responses are mediated via changes in glucose handling, whereas alterations in fat metabolism likely represent maladaptation.

Anaplastic ganglioglioma arising from a Lhermitte-Duclos-like lesion. Case report

The authors report the case of a 7-year-old boy with a history of developmental delay who presented with aggressive behavior. A magnetic resonance (MR) image showed a mass lesion originating from the cerebellar vermis with an atypical folial pattern and contrast enhancement. Histologically, the subtotally resected specimen consisted mostly of neuropil with nodular foci of ganglion cells. Lhermitte-Duclos disease (LDD) was diagnosed in the patient. A retrospective review of the tissue sections showed a nidus of associated astrocytic proliferation, suggesting a diagnosis of ganglioglioma. Five years later, the patient experienced an altered mental state and a facial droop. An MR image revealed a cerebellar mass with cystic areas and an enhancing nodule. The resected tissue specimen consisted primarily of a mixed proliferation of glial and ganglion cells consistent with a ganglioglioma. Two years later, a third craniectomy was performed in the patient for worsening headache and ataxia. Histologically, the tumor showed progressive anaplasia and was most accurately classified as an anaplastic ganglioglioma. Immunohistochemically, most of the tumor cells were immunoreactive for anti-phospho-mammalian target of rapamycin (mTOR) and phospho-S6 ribosomal protein antibodies. In contrast, the subpopulation of neoplastic ganglion cells in the tissue, particularly from the first surgery, did not express phosphatase and tensin homolog deleted from chromosome 10 (PTEN). This immunohistochemical pattern suggests that the large dysplastic ganglion cells (the gangliocytomatous component) forming the greater part of the lesion were associated with activation of the phosphatidylinositol 3-kinase-PTEN/Akt/mTOR signaling pathway, a feature previously reported in LDD. This case represents the first report of an anaplastic ganglioglioma arising in an LDD-like lesion.

Diagnosing cranial fasciitis based on distinguishing radiological features

Primary skull lesions, albeit rare in the pediatric population, have been well described and classified. These lesions are usually benign and commonly present as a painless mass. The most common lesions are epidermoid, dermoid, and Langerhans cell histiocytosis. Cranial fasciitis, encountered less frequently, is usually not considered in this differential diagnosis. Given such few cases reported, it is commonly misdiagnosed preoperatively. The authors retrospectively reviewed data obtained in 4 patients with cranial fasciitis in whom the diagnosis was based on histopathological findings. In 2 patients the onset of the lesion was spontaneous. One patient had a lesion 4 months following a vacuum extraction and subsequent cephalohematoma formation. One patient developed a lesion following a previous craniectomy. Presentation, imaging studies, and histopathological findings were all reviewed and analyzed. All patients presented with a firm nontender mass. Radiological features included a lytic bone lesion with a mildly sclerotic margin, T1 isodensity, T2 heterogeneous hyperdensity, and heterogeneous enhancement. The enhancing portion was not bright on T2-weighted MR images, likely representing the fibrous component; the nonenhancing portion was bright on T2-weighted images, likely representing the myxoid matrix. Histopathological examination revealed proliferating fibroblasts in a myxoid matrix. Cranial fasciitis is a benign, painless but rapidly growing lesion of the skull mainly limited to the pediatric population. It is histologically similar to nodular fasciitis, a fibroblastic proliferation of varying size. These lesions are often related to trauma but can also be insidious or can develop at a prior craniectomy site. The appropriate clinical picture and distinguishing radiographic features may help to differentiate cranial fasciitis from other lesions of the skull allowing for earlier intervention.

Cytologic features of subependymal giant cell astrocytom: a review of 7 cases

OBJECTIVE

To describe the cytologic features of subependymal giant cell astrocytoma (SEGA) on smears and analyze cytomorphologic parameters that may help in reaching the diagnosis of SEGA.

STUDY DESIGN

Cytologic smears of 7 cases of SEGA were reviewed and graded semi-quantitatively for 11 cytologic features: clustering, cytoplasmic fibrillary processes (fibrillarity), cellularity, small prominent nudcleoli, binucleation or multinucleation, "strap cells", spindle-shaped cells, mitoses, intranuclear inclusions, nuclear atypia and perivascular palisading/pseudorosettes. Corresponding histologic sections were also reviewed.

RESULTS

The study included 5 male and 2 female patients with an average age of 8.3 years (range, 3-16) at surgery. Cytologic examination revealed loosely cohesive clusters of large cells possessing round to oval nuclei with no or minimal atypia; fine, evenly distributed chromatin; and abundant eosinophilic cytoplasm enmeshed in abundant thin, hairlike processes. Predominant features included hypercellularity, cell clustering, and fibrillarity. Binucleation or multinucleation; small, prominent nucleoli; and strap cells were often seen. Although common in histologic sections, perivascular palisading/pseudorosettes and spindled astrocytic cells were rarely noted on smears.

CONCLUSION

The cytologic features of SEGA are highly characteristic and thus are of great use in supporting a diagnosis of SEGA and in excluding mimics, primarily gemistocytic astrocytoma and ependymoma.

Brain proton magnetic resonance spectroscopy and neuromuscular pathology in a patient with GM1 gangliosidosis

The authors report the clinical, neuroradiologic, and neuromuscular pathological findings in a patient with GM1 gangliosidosis. The proton magnetic resonance spectroscopy, previously reported in a single patient with GM1 gangliosidosis, detected a mild reduction of N-acetylaspartate, consistent with relative paucity of axons and neurons and increased levels of myoinositol suggestive of gliotic white matter changes along with the accumulation of an additional compound that could represent either guanidinoacetate or Gal beta 1-6Gal beta 1-4)GlcNAc, an oligosaccharide previously isolated from the urine of GM1 gangliosidosis patients. Although these findings will have to be further confirmed in more patients with GM1 gangliosidosis, they suggest that proton magnetic resonance spectroscopy may provide useful end points to assess the efficacy of novel treatments that could soon become clinically available. Histologically, no significant alterations were found in axons, but there was evidence of redundant and inappropriately folded myelin, which is a feature attributed to disturbed axon-glial interactions.

Spinocerebellar ataxia with axonal neuropathy: consequence of a Tdp1 recessive neomorphic mutation?

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) cleaves the phosphodiester bond between a covalently stalled topoisomerase I (Topo I) and the 3' end of DNA. Stalling of Topo I at DNA strand breaks is induced by endogenous DNA damage and the Topo I-specific anticancer drug camptothecin (CPT). The H493R mutation of Tdp1 causes the neurodegenerative disorder spinocerebellar ataxia with axonal neuropathy (SCAN1). Contrary to the hypothesis that SCAN1 arises from catalytically inactive Tdp1, Tdp1-/- mice are indistinguishable from wild-type mice, physically, histologically, behaviorally, and electrophysiologically. However, compared to wild-type mice, Tdp1-/- mice are hypersensitive to CPT and bleomycin but not to etoposide. Consistent with earlier in vitro studies, we show that the H493R Tdp1 mutant protein retains residual activity and becomes covalently trapped on the DNA after CPT treatment of SCAN1 cells. This result provides a direct demonstration that Tdp1 repairs Topo I covalent lesions in vivo and suggests that SCAN1 arises from the recessive neomorphic mutation H493R. This is a novel mechanism for disease since neomorphic mutations are generally dominant.

The Angelman syndrome ubiquitin ligase localizes to the synapse and nucleus, and maternal deficiency results in abnormal dendritic spine morphology

Loss of function of the maternally inherited allele for the UBE3A ubiquitin ligase gene causes Angelman syndrome (AS), which is characterized by severe neurological impairment and motor dysfunction. In addition, UBE3A lies within chromosome 15q11-q13 region, where maternal, but not paternal, duplications cause autism. The UBE3A gene product, E6-AP, has been shown to function both as an E3 ligase in the ubiquitin proteasome pathway and as a transcriptional coactivator. However, the specific role of E6-AP in the brain, or how loss of function of E6-AP results in AS, is unclear. Herein, we show, using a recombinant transgenic mouse expressing a Ube3a(YFP) fusion gene, that the maternal Ube3a(YFP) allele is upregulated and preferentially expressed in neurons, and that the fusion protein, E6-AP:YFP, is enriched in the nucleus and dendrites in vivo. We also show that E6-AP:YFP localizes to the nucleus and to presynaptic and postsynaptic compartments in cultured hippocampal neurons. Furthermore, we show that cerebellar Purkinje cell number and dendritic branching are not affected in Ube3a maternal-deficient mice, but that dendritic spine development, including spine morphology, number and length, is affected on cerebellar Purkinje cells and on pyramidal neurons in the hippocampus and cortex. Collectively, these data suggest that the neurological deficits observed in AS patients and in AS mice may result from specific abnormalities in synaptic development and/or plasticity.