Liquid biopsy-based circulating tumour (ct)DNA analysis of a spectrum of myeloid and lymphoid malignancies yields clinically actionable results

AIMS

Liquid biopsy (LBx)-based next-generation sequencing (NGS) of circulating tumour DNA (ctDNA) can facilitate molecular profiling of haematopoietic neoplasms (HNs), particularly when tissue-based NGS is infeasible.

METHODS AND RESULTS

We studied HN LBx samples tested with FoundationOne Liquid CDx, FoundationOne Liquid, or FoundationACT between July 2016 and March 2022. We identified 271 samples: 89 non-Hodgkin lymphoma (NHL), 43 plasma-cell neoplasm (PCN), 41 histiocytoses, 27 myelodysplastic syndrome (MDS), 25 diffuse large B-cell lymphoma (DLBCL), 22 myeloproliferative neoplasm (MPN), 14 Hodgkin lymphoma (HL), and 10 acute myeloid leukaemia (AML). Among 73.4% with detectable pathogenic alterations, median maximum somatic allele frequency (MSAF) was 16.6%, with AML (36.2%), MDS (19.7%), and MPN (44.5%) having higher MSAFs than DLBCL (3.9%), NHL (8.4%), HL (1.5%), PCN (2.8%), and histiocytoses (1.8%) (P = 0.001). LBx detected characteristic alterations across HNs, including in TP53, KRAS, MYD88, and BTK in NHLs; TP53, KRAS, NRAS, and BRAF in PCNs; IGH in DLBCL; TP53, ATM, and PDCD1LG2 in HL; BRAF and MAP2K1 in histiocytoses; TP53, SF3B1, DNMT3A, TET2, and ASXL1 in MDS; JAK2 in MPNs; and FLT3, IDH2, and NPM1 in AML. Among 24 samples, the positive percent agreement by LBx was 75.7% for variants present in paired buffy coat, marrow, or tissues. Also, 75.0% of pairs exhibited alterations only present on LBx. These were predominantly subclonal (clonal fraction of 3.8%), reflecting the analytical sensitivity of LBx.

CONCLUSION

These data demonstrate that LBx can detect relevant genomic alterations across HNs, including at low clonal fractions, suggesting a potential clinical utility for identifying residual or emerging therapy-resistant clones that may be undetectable in site-specific tissue biopsies.

Brain tumors in United States military veterans

BACKGROUND

Comprehensive analysis of brain tumor incidence and survival in the Veteran population has been lacking.

METHODS

Veteran data were obtained from the Veterans Health Administration (VHA) Medical Centers via VHA Corporate Data Warehouse. Brain tumor statistics on the overall US population were generated from the Central Brain Tumor Registry of the US data. Cases were individuals (≥18 years) with a primary brain tumor, diagnosed between 2004 and 2018. The average annual age-adjusted incidence rates (AAIR) and 95% confidence intervals were estimated per 100 000 population and Kaplan-Meier survival curves evaluated overall survival outcomes among Veterans.

RESULTS

The Veteran population was primarily white (78%), male (93%), and between 60 and 64 years old (18%). Individuals with a primary brain tumor in the general US population were mainly female (59%) and between 18 and 49 years old (28%). The overall AAIR of primary brain tumors from 2004 to 2018 within the Veterans Affairs cancer registry was 11.6. Nonmalignant tumors were more common than malignant tumors (AAIR:7.19 vs 4.42). The most diagnosed tumors in Veterans were nonmalignant pituitary tumors (AAIR:2.96), nonmalignant meningioma (AAIR:2.62), and glioblastoma (AAIR:1.96). In the Veteran population, survival outcomes became worse with age and were lowest among individuals diagnosed with glioblastoma.

CONCLUSIONS

Differences between Veteran and US populations can be broadly attributed to demographic composition differences of these groups. Prior to this, there have been no reports on national-level incidence rates and survival outcomes for Veterans. These data provide vital information that can drive efforts to understand disease burden and improve outcomes for individuals with primary brain tumors.

Patterns of TDP-43 Deposition in Brains with LRRK2 G2019S Mutations

OBJECTIVE

To assess for TDP-43 deposits in brains with and without a LRRK2 G2019S mutation.

BACKGROUND

LRRK2 G2019S mutations have been associated with parkinsonism and a wide range of pathological findings. There are no systematic studies examining the frequency and extent of TDP-43 deposits in neuropathological samples from LRRK2 G2019S carriers.

METHODS

Twelve brains with LRRK2 G2019S mutations were available for study from the New York Brain Bank at Columbia University; 11 of them had samples available for TDP-43 immunostaining. Clinical, demographic, and pathological data are reported for 11 brains with a LRRK2 G2019S mutation and compared to 11 brains without GBA1 or LRRK2 G2019S mutations with a pathologic diagnosis of Parkinson's disease (PD) or diffuse Lewy body disease. They were frequency matched by age, gender, parkinsonism age of onset, and disease duration.

RESULTS

TDP-43 aggregates were present in 73% (n = 8) of brains with a LRRK2 mutation and 18% (n = 2) of brains without a LRRK2 mutation (P = 0.03). In one brain with a LRRK2 mutation, TDP-43 proteinopathy was the primary neuropathological change.

CONCLUSIONS

Extranuclear TDP-43 aggregates are observed with greater frequency in LRRK2 G2019S autopsies compared to PD cases without a LRRK2 G2019S mutation. The association between LRRK2 and TDP-43 should be further explored. © 2023 International Parkinson and Movement Disorder Society.

Precision diagnosis and staging of TDP-43 proteinopathies: harnessing the power of artificial intelligence

This scientific commentary refers to ‘Data-driven neuropathological staging and subtyping of TDP-43 proteinopathies’ by Young et al. (https://doi.org/10.1093/brain/awad145).

Cerebrospinal fluid: A unique source of circulating tumor DNA with broad clinical applications

Malignancies involving the central nervous system present unique challenges for diagnosis and monitoring due to the difficulties and risks of direct biopsies and the low specificity and/or sensitivity of other techniques for assessment. In recent years, liquid biopsy of the cerebrospinal fluid (CSF) has emerged as a convenient alternative that combines minimal invasiveness with the ability to detect disease-defining or therapeutically actionable genetic alterations from circulating tumor DNA (ctDNA). Since CSF can be obtained by lumbar puncture, or an established ventricular access device at multiple time points, ctDNA analysis enables initial molecular characterization and longitudinal monitoring throughout a patient's disease course, promoting optimization of treatment regimens. This review outlines some of the key aspects of ctDNA from CSF as a highly suitable approach for clinical assessment, the benefits and drawbacks, testing methods, as well as potential future advancements in this field. We anticipate wider adoption of this practice as technologies and pipelines improve and envisage significant improvements for cancer care.

Huntington disease oligodendrocyte maturation deficits revealed by single-nucleus RNAseq are rescued by thiamine-biotin supplementation

The complexity of affected brain regions and cell types is a challenge for Huntington's disease (HD) treatment. Here we use single nucleus RNA sequencing to investigate molecular pathology in the cortex and striatum from R6/2 mice and human HD post-mortem tissue. We identify cell type-specific and -agnostic signatures suggesting oligodendrocytes (OLs) and oligodendrocyte precursors (OPCs) are arrested in intermediate maturation states. OL-lineage regulators OLIG1 and OLIG2 are negatively correlated with CAG length in human OPCs, and ATACseq analysis of HD mouse NeuN-negative cells shows decreased accessibility regulated by OL maturation genes. The data implicates glucose and lipid metabolism in abnormal cell maturation and identify PRKCE and Thiamine Pyrophosphokinase 1 (TPK1) as central genes. Thiamine/biotin treatment of R6/1 HD mice to compensate for TPK1 dysregulation restores OL maturation and rescues neuronal pathology. Our insights into HD OL pathology spans multiple brain regions and link OL maturation deficits to abnormal thiamine metabolism.

Toward Precision Phenotyping of Multiple Sclerosis

The classification of multiple sclerosis (MS) has been established by Lublin in 1996 and revised in 2013. The revision includes clinically isolated syndrome, relapsing-remitting, primary progressive and secondary progressive MS, and has added activity (i.e., formation of white matter lesions or clinical relapses) as a qualifier. This allows for the distinction between active and nonactive progression, which has been shown to be of clinical importance. We propose that a logical extension of this classification is the incorporation of additional key pathological processes, such as chronic perilesional inflammation, neuroaxonal degeneration, and remyelination. This will distinguish MS phenotypes that may present as clinically identical but are driven by different combinations of pathological processes. A more precise description of MS phenotypes will improve prognostication and personalized care as well as clinical trial design. Thus, our proposal provides an expanded framework for conceptualizing MS and for guiding development of biomarkers for monitoring activity along the main pathological axes in MS.

The distribution and density of Huntingtin inclusions across the Huntington disease neocortex: regional correlations with Huntingtin repeat expansion independent of pathologic grade

Huntington disease is characterized by progressive neurodegeneration, especially of the striatum, and the presence of polyglutamine huntingtin (HTT) inclusions. Although HTT inclusions are most abundant in the neocortex, their neocortical distribution and density in relation to the extent of CAG repeat expansion in the HTT gene and striatal pathologic grade have yet to be formally established. We immunohistochemically studied 65 brains with a pathologic diagnosis of Huntington disease to investigate the cortical distributions and densities of HTT inclusions within the calcarine (BA17), precuneus (BA7), motor (BA4) and prefrontal (BA9) cortices; in 39 of these brains, a p62 immunostain was used for comparison. HTT inclusions predominate in the infragranular cortical layers (layers V-VI) and layer III, however, the densities of HTT inclusions across the human cerebral cortex are not uniform but are instead regionally contingent. The density of HTT and p62 inclusions (intranuclear and extranuclear) in layers V-VI increases caudally to rostrally (BA17 < BA7 < BA4 < BA9) with the median burden of HTT inclusions being 38-fold greater in the prefrontal cortex (BA9) than in the calcarine cortex (BA17). Conversely, intranuclear HTT inclusions prevail in the calcarine cortex irrespective of HTT CAG length. Neocortical HTT inclusion density correlates with CAG repeat expansion, but not with the neuropathologic grade of striatal degeneration (Vonsattel grade) or with the duration of clinical disease since motor onset. Extrapolation of these findings suggest that HTT inclusions are at a regionally-contingent, CAG-dependent, density during the advanced stages of HD. The distribution and density of HTT inclusions in HD therefore does not provide a measure of pathologic disease stage but rather infers the degree of pathogenic HTT expansion.

Pituitary corticotroph tumour with adrenocortical cells: A distinct clinicopathologic entity with unique morphology and methylation profile

We describe a rare TPIT-positive corticotroph PitNET that is admixed with SF1-positive adrenocortical cells. This dimorphous population of cells showed no colocalisation between TPIT and SF1 by immunofluorescence, and an adrenocortical choristoma was favoured. Methylation array analysis revealed a novel methylation profile in relation to other pituitary neoplasms.

COVID-19 neuropathology at Columbia University Irving Medical Center/New York Presbyterian Hospital

Many patients with SARS-CoV-2 infection develop neurological signs and symptoms; although, to date, little evidence exists that primary infection of the brain is a significant contributing factor. We present the clinical, neuropathological and molecular findings of 41 consecutive patients with SARS-CoV-2 infections who died and underwent autopsy in our medical centre. The mean age was 74 years (38-97 years), 27 patients (66%) were male and 34 (83%) were of Hispanic/Latinx ethnicity. Twenty-four patients (59%) were admitted to the intensive care unit. Hospital-associated complications were common, including eight patients (20%) with deep vein thrombosis/pulmonary embolism, seven (17%) with acute kidney injury requiring dialysis and 10 (24%) with positive blood cultures during admission. Eight (20%) patients died within 24 h of hospital admission, while 11 (27%) died more than 4 weeks after hospital admission. Neuropathological examination of 20-30 areas from each brain revealed hypoxic/ischaemic changes in all brains, both global and focal; large and small infarcts, many of which appeared haemorrhagic; and microglial activation with microglial nodules accompanied by neuronophagia, most prominently in the brainstem. We observed sparse T lymphocyte accumulation in either perivascular regions or in the brain parenchyma. Many brains contained atherosclerosis of large arteries and arteriolosclerosis, although none showed evidence of vasculitis. Eighteen patients (44%) exhibited pathologies of neurodegenerative diseases, which was not unexpected given the age range of our patients. We examined multiple fresh frozen and fixed tissues from 28 brains for the presence of viral RNA and protein, using quantitative reverse-transcriptase PCR, RNAscope® and immunocytochemistry with primers, probes and antibodies directed against the spike and nucleocapsid regions. The PCR analysis revealed low to very low, but detectable, viral RNA levels in the majority of brains, although they were far lower than those in the nasal epithelia. RNAscope® and immunocytochemistry failed to detect viral RNA or protein in brains. Our findings indicate that the levels of detectable virus in coronavirus disease 2019 brains are very low and do not correlate with the histopathological alterations. These findings suggest that microglial activation, microglial nodules and neuronophagia, observed in the majority of brains, do not result from direct viral infection of brain parenchyma, but more likely from systemic inflammation, perhaps with synergistic contribution from hypoxia/ischaemia. Further studies are needed to define whether these pathologies, if present in patients who survive coronavirus disease 2019, might contribute to chronic neurological problems.

R1441G but not G2019S mutation enhances LRRK2 mediated Rab10 phosphorylation in human peripheral blood neutrophils

Heterozygous gain-of-kinase function variants in LRRK2 (leucine-rich repeat kinase 2) cause 1-2% of all cases of Parkinson's disease (PD) albeit with incomplete and age-dependent penetrance. All pathogenic LRRK2 mutations reside within the two catalytic domains of LRRK2-either in its kinase domain (e.g. G2019S) with modest effect or its ROC-COR GTPase domain (e.g. R1441G/H) with large effect on LRRK2 kinase activity. We have previously reported assays to interrogate LRRK2 kinase pathway activity in human bio-samples measuring phosphorylation of its endogenous substrate Rab10, that mirrors LRRK2 kinase activation status. Here, we isolated neutrophils from fresh peripheral blood from 101 participants including 42 LRRK2 mutation carriers (21 with the G2019S and 21 with the R1441G mutations), 27 patients with idiopathic PD, and 32 controls. Using a dual approach, LRRK2 dependent Rab10 phosphorylation at Threonine 73 (pRab10Thr73) was measured by quantitative multiplexed immunoblotting for pRab10Thr73/total Rab10 as well as targeted mass-spectrometry for absolute pRab10Thr73 occupancy. We found a significant over fourfold increase in pRab10Thr73 phosphorylation in carriers of the LRRK2 R1441G mutation irrespective of clinical disease status. The effect of the LRRK2 G2019S mutation did not reach statistical significance. Furthermore, we show that LRRK2 phosphorylation at Serine 935 is not a marker for LRRK2 kinase activity in human neutrophils. When analysing pRab10Thr73 phosphorylation in post-mortem brain samples, we observed overall high variability irrespective of clinical and LRRK2 mutation status and attributed this mainly to the adverse effect of the peri- and post-mortem period on the stability of posttranslational modifications such as protein phosphorylation. Overall, in vivo LRRK2 dependent pRab10Thr73 phosphorylation in human peripheral blood neutrophils is a specific, robust and promising biomarker for significant LRRK2 kinase hyperactivation, as with the LRRK2 R1441G mutation. Additional readouts and/or assays may be needed to increase sensitivity to detect modest LRRK2 kinase activation, as with the LRRK2 G2019S mutation. Our assays could be useful for patient stratification and target engagement studies for LRRK2 kinase inhibitors.

Neuropathological Findings in a Case of Parkinsonism and Developmental Delay Associated with a Monoallelic Variant in PLXNA1

BACKGROUND

PLXNA1 encodes for Plexin-A, a transmembrane protein expressed in the developing nervous system. Mutations in this gene have been associated with developmental delay but have not been previously associated with the development of parkinsonism.

OBJECTIVES

To describe the case of a 38-year-old patient with developmental delay who developed parkinsonism later in life.

METHODS

Post-mortem exome sequencing was performed with confirmation by Sanger sequencing. Brain autopsy was also performed.

RESULTS

Post-mortem exome sequencing on the proband identified a heterozygous predicted nonsense PLXNA1 variant (c.G3361T:p.Glu1121Ter). Pathology demonstrated arhinencephaly with brainstem heterotopia, diffuse Lewy body disease, and frontotemporal lobar dementia-tau.

CONCLUSIONS

This case of a patient with developmental delay and parkinsonism with PLXNA1 mutation highlights a need for assessing long-term outcomes of individuals with neurodevelopmental disorders, as well as the need for genetic testing in adults. It also suggests that the link between PLXNA1 and α-synuclein should be explored in the future. © 2021 International Parkinson and Movement Disorder Society.

Developmental malformations in Huntington disease: neuropathologic evidence of focal neuronal migration defects in a subset of adult brains

Neuropathologic hallmarks of Huntington Disease (HD) include the progressive neurodegeneration of the striatum and the presence of Huntingtin (HTT) aggregates that result from abnormal polyQ expansion of the HTT gene. Whether the pathogenic trinucleotide repeat expansion of the HTT gene causes neurodevelopmental abnormalities has garnered attention in both murine and human studies; however, documentation of discrete malformations in autopsy brains of HD individuals has yet to be described. We retrospectively searched the New York Brain Bank (discovery cohort) and an independent cohort (validation cohort) to determine whether developmental malformations are more frequently detected in HD versus non-HD brains and to document their neuropathologic features. One-hundred and thirty HD and 1600 non-HD whole brains were included in the discovery cohort and 720 HD and 1989 non-HD half brains were assessed in the validation cohort. Cases with developmental malformations were found at 6.4–8.2 times greater frequency in HD than in non-HD brains (discovery cohort: OR 8.68, 95% CI 3.48–21.63, P=4.8 × 10^-5; validation cohort: OR 6.50, 95% CI 1.83–23.17, P=0.0050). Periventricular nodular heterotopias (PNH) were the most frequent malformations and contained HTT and p62 aggregates analogous to the cortex, whereas cortical malformations with immature neuronal populations did not harbor such inclusions. HD individuals with malformations had heterozygous HTT CAG expansions between 40 and 52 repeats, were more frequently women, and all were asymmetric and focal, aside from one midline hypothalamic hamartoma. Using two independent brain bank cohorts, this large neuropathologic series demonstrates an increased occurrence of developmental malformations in HD brains. Since pathogenic HTT gene expansion is associated with genomic instability, one possible explanation is that neuronal precursors are more susceptible to somatic mutation of genes involved in cortical migration. Our findings further support emerging evidence that pathogenic trinucleotide repeat expansions of the HTT gene may impact neurodevelopment.

Pathogenic Huntingtin Repeat Expansions in Patients with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis

We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40-64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington's disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered.

Gonadotroph tumours with a low SF-1 labelling index are more likely to recur and are associated with enrichment of the PI3K-AKT pathway

AIMS

The gonadotroph tumour (GT) is the most frequently resected pituitary neuroendocrine tumour. Although many symptomatic GT are successfully resected, some recur. We sought to identify histological biomarkers that may predict recurrence and explore biological mechanisms that explain this difference in behaviour.

METHODS

SF-1 immunohistochemistry of 51 GT, a subset belonging to a longitudinal prospective cohort study (n = 25), was reviewed. Four groups were defined: Group 1-recently diagnosed GT (n = 20), Group 2-non-recurrent GT with long-term follow up (n = 11), Group 3-initial resections of GT that recur (n = 7) and Group 4-recurrent GT (n = 13). The percentage of SF-1 immunolabelling in the lowest staining fields (SF-1 labelling index (SLI)) was assessed and RNA sequencing was performed on 5 GT with SLI <80% and 5 GT with SLI >80%.

RESULTS

Diffuse, strong SF-1 immunolabelling was the most frequent pattern in Groups 1/2, whereas patchy SF-1 staining predominated in Groups 3/4. There was a lower median SLI in Groups 3/4 than 1/2. Overall, GT with SLI <80% recurred earlier than GT with SLI >80%. Differential expression analysis identified 89 statistically significant differentially expressed genes (FDR <0.05) including over-expression of pituitary stem cell genes (SOX2, GFRA3) and various oncogenes (e.g. BCL2, ERRB4) in patchy SF-1 GT. Gene set enrichment analysis identified significant enrichment of genes involved in the PI3K-AKT pathway.

CONCLUSIONS

We speculate that patchy SF-1 labelling in GT reflects intratumoural heterogeneity and are less differentiated tumours than diffusely staining GT. SF-1 immunolabelling patterns may have prognostic significance in GT, but confirmatory studies are needed for further validation.

Neuronophagia and microglial nodules in a SARS-CoV-2 patient with cerebellar hemorrhage

We document the neuropathologic findings of a 73-year old man who died from acute cerebellar hemorrhage in the context of relatively mild SARS-CoV2 infection. The patient developed sudden onset of headache, nausea, and vomiting, immediately followed by loss of consciousness on the day of admission. Emergency medical services found him severely hypoxemic at home, and the patient suffered a cardiac arrest during transport to the emergency department. The emergency team achieved return of spontaneous circulation after over 17 min of resuscitation. A chest radiograph revealed hazy bilateral opacities; and real-time-PCR for SARS-CoV-2 on the nasopharyngeal swab was positive. Computed tomography of the head showed a large right cerebellar hemorrhage, with tonsillar herniation and intraventricular hemorrhage. One day after presentation, he was transitioned to comfort care and died shortly after palliative extubation. Autopsy performed 3 h after death showed cerebellar hemorrhage and acute infarcts in the dorsal pons and medulla. Remarkably, there were microglial nodules and neuronophagia bilaterally in the inferior olives and multifocally in the cerebellar dentate nuclei. This constellation of findings has not been reported thus far in the context of SARS-CoV-2 infection.

Primary Age-Related Tauopathy (PART): Addressing the Spectrum of Neuronal Tauopathic Changes in the Aging Brain

PURPOSE OF REVIEW

Primary age-related tauopathy (PART) was recently proposed as a pathologic diagnosis for brains that harbor neurofibrillary tangles (Braak stage ≤ 4) with little, if any, amyloid burden. We sought to review the clinicopathologic findings related to PART.

RECENT FINDINGS

Most adult human brains show at least focal tauopathic changes, and the majority of individuals with PART do not progress to dementia. Older age and cognitive impairment correlate with increased Braak stage, and multivariate analyses suggest that the rate of cognitive decline is less than matched patients with Alzheimer disease (AD). It remains unclear whether PART is a distinct tauopathic entity separate from AD or rather represents an earlier histologic stage of AD. Cognitive decline in PART is usually milder than AD and correlates with tauopathic burden. Biomarker and ligand-based radiologic studies will be important to define PART antemortem and prospectively follow its natural history.

Meningomyeloencephalitis secondary to Mycobacterium haemophilum infection in AIDS

Infections by opportunistic non-tuberculous mycobacteria (NTM) are rising in global incidence. One emerging, slowly growing NTM is Mycobacterium haemophilum, which can cause skin, lung, bone, and soft tissue infections in immunocompromised patients as well as lymphadenitis in immunocompetent individuals. Detection of this microorganism is difficult using conventional culture-based methods and few reports have documented involvement of this pathogen within the central nervous system (CNS).

We describe the neuropathologic autopsy findings of a 39-year-old man with AIDS who died secondary to M. haemophilum CNS infection. He initially presented with repeated bouts of pyrexia, nausea and vomiting, and altered mental status that required numerous hospitalizations. CSF infectious workups were consistently negative. His most recent admission identified hyperintensities within the brainstem by MRI and despite antibiotic therapies for suspected CNS infection, he died. Autopsy revealed a swollen brain with marked widening of the brainstem. Microscopic examination of the brain and spinal cord showed focal lymphohistiocytic infiltrates, gliosis and neuronal loss that were associated with acid-fast bacilli (AFB). The brainstem was the most severely damaged and AFB were found to congregate along arterial territories lending support to the notion of hematogenous spread as a mechanism for the organisms’ dissemination. 16S rRNA sequencing on formalin-fixed paraffin-embedded tissue enabled post-mortem identification of M. haemophilum. This sequencing methodology may permit diagnosis on CSF intra-vitam.

Rasmussen Encephalitis: An Update

Rasmussen encephalitis (RE) is a rare, devastating, progressive pediatric epilepsy. First described 60 years ago, RE continues to present challenges in diagnosis and management. RE causes a unilateral focal epilepsy in children that typically becomes medically refractory, results in significant hemiparesis, and causes progressive cognitive decline. The etiology is a cell-mediated immune attack on one cerebral hemisphere, though the inciting antigen remains unknown. While the underlying histopathology is unilateral and RE is described as "unihemispheric," studies have demonstrated (1) atrophy of the unaffected hemisphere, (2) electroencephalographic abnormalities (slowing and spikes) in the unaffected hemisphere, and (3) cognitive decline referable to the unaffected hemisphere. These secondary contralateral effects likely reflect the impact of uncontrolled epileptic activity (i.e., epileptic encephalopathy). Hemispheric disconnection (HD) renders 70 to 80% of patients seizure free. While it has the potential to limit the influence of seizures and abnormal electrical activity emanating from the pathological hemisphere, HD entails hemiparesis and hemianopia, as well as aphasia for patients with dominant HD. With the recent expansion of available immunomodulatory therapies, there has been interest in identifying an alternative to HD, though evidence for disease modification is limited to date. We review what is known and what remains unknown about RE.

Presenting Features in 269 Patients With Clinically Nonfunctioning Pituitary Adenomas Enrolled in a Prospective Study

Context

Clinically nonfunctioning pituitary adenomas (CNFPAs) typically remain undetected until mass effect symptoms develop. However, currently, head imaging is performed commonly for many other indications, which may increase incidental discovery of CNFPAs. Since current presentation and outcome data are based on older, retrospective series, a prospective characterization of a contemporary CNFPA cohort was needed.

Objective

To determine the prevalence of incidental presentation and hypopituitarism and its predictors in a CNFPA cohort that spanned 6 to 9 mm micro- to macroadenoma included observational and surgical therapy.

Methods

At enrollment in a prospective, observational study, 269 patients with CNFPAs were studied by history, examination, blood sampling, and pituitary imaging analysis and categorized into incidental or symptoms presentation groups that were compared.

Results

Presentation was incidental in 48.7% of patients and due to tumor symptoms in 51.3%. In the symptoms and incidental groups, 58.7% and 27.4% of patients had hypopituitarism, respectively, and 25% of patients with microadenomas had hypopituitarism. Many had unappreciated signs and symptoms of pituitary disease. Most tumors were macroadenomas (87%) and were larger in the symptoms than incidental and hypopituitary groups than in the eupituitary groups. The patients in the incidental group were older, and males were older and had larger tumors in both the incidental and symptoms groups.

Conclusions

Patients with CNFPAs commonly present incidentally and with previously unrecognized hypopituitarism and symptoms that could have prompted earlier diagnosis. Our data support screening all large micro and macro-CNFPAs for hypopituitarism. Most patients with CNFPAs still have mass effect signs at presentation, suggesting the need for more awareness of pituitary disease. Our ongoing, prospective observation of this cohort will assess outcomes of these CNFPA groups.

A rare case of anal carcinosarcoma with human papilloma virus infection in both biphasic tumor elements: An immunohistochemical, molecular and ultrastructural study

Carcinosarcoma of the anus is rare and has yet to be reportedly associated with the keratinocyte-specific Human Papilloma Virus (HPV). We describe a case of anal carcinosarcoma with HPV infection in both the epithelial and mesenchymal components of the tumor by immunohistochemistry, chromogenic in-situ hybridization (CISH) and further supported by electron microscopy (EM). Microscopic examination of the tumor showed nests of poorly-differentiated invasive squamous cell carcinoma with basaloid features intermixed with a hypercellular, atypical spindle cell proliferation. Immunohistochemistry demonstrated that the epithelial component was positive for AE1/AE3, p63, CK5/6 and p16, whilst the mesenchymal component was positive for smooth muscle actin, vimentin, and focally positive for desmin and p16, consistent with carcinosarcoma. The tumor was negative for GATA-3, CK7 and CK20. CISH demonstrated that the tumor was positive for high risk HPV (subtype 16/18) in both tumor components. EM further supported the presence of intracellular virus particles (~50 nm) that is compatible with HPV infection. Infection of both epithelial and mesenchymal tumor components by HPV has not been previously observed in the gastrointestinal tract. This finding may represent initial epithelial HPV infection with subsequent divergent tumoral differentiation and suggests the presence of viral replication in both biphasic tumor components.

Reassuringly low carriage of enteropathogens among healthy Swedish children in day care centres

OBJECTIVES

Infectious gastroenteritis is one of the most common diseases among children and has a considerable impact on health and socio-economy. Day care centres are high-risk environments for infections. The aim of this study was to investigate if asymptomatic preschool children constitute a reservoir for potential enteropathogens.

STUDY DESIGN

In total, 438 individual diapers were collected from day care centres in Uppsala, Sweden, during spring and autumn, and molecular techniques were used to estimate the prevalence of asymptomatic carriage of multiple enteropathogens.

METHODS

Faecal samples were analysed with multiplex polymerase chain reaction (PCR) (xTAG^® Gastrointestinal Pathogen Panel; Luminex Corporation, Toronto, Canada) targeting 21 different pathogens. Samples with a median fluorescence intensity above threshold were re-analysed with a second PCR assay.

RESULTS

Sixteen of the 438 samples were positive for enteropathogens, 1.6% for enteric adenovirus, 0.7% for Campylobacter spp., and 0.7% for norovirus.

CONCLUSIONS

Preschool children in Uppsala constitute a limited reservoir for potential enteropathogens.

The efficacy and safety of rituximab in a chart review study of 15 patients with systemic lupus erythematosus

In contrast to randomised clinical trials, open-label studies have suggested that B cell depletion by a course of rituximab is associated with a significant clinical benefit. Our aim was to assess the safety and efficacy of rituximab in 15 refractory lupus patients, particularly those with more than one course of therapy. Disease activity was measured by the classic British Isles Lupus Assessment Group (BILAG) index, anti-DNA antibodies and complement levels. We assessed immunoglobulin levels, functional antibodies and serious adverse events. The mean patient age ± SD was 37.9 ± 7.2 years and mean disease duration was 8.5 ± 3.3 years; 46% were Afro-Caribbean, 27% South Asian, 20% Caucasian and 7% others. Twelve patients responded by 6 months; six avoided major flare for >1 year. Complete absence of disease activity (BILAG D/E) lasted for 5.5 (SD 3.8) months and 4.8 (SD 3.6) months after the first (n = 15) and second (n = 9) rituximab course, respectively. The mean 6-month reduction in daily prednisolone was 10.4 (SD 11.4) mg/day and 10.7 (SD 9.3) mg/day from baseline after the first and second course, respectively. Patients with low C3/C4 normalised their C3 by 6 months. Most patients with raised anti-dsDNA normalised after rituximab courses. Serious adverse events only occurred after more than four courses of rituximab. Rituximab was safe and efficacious for treating patients with refractory systemic lupus erythematosus (SLE) and was associated with significant steroid reduction, but more than four courses of rituximab was associated with an increased risk of serious infection in two patients.

Cell-wall-inhibiting antibiotic combinations with activity against multidrug-resistant Klebsiella pneumoniae and Escherichia coli

The increasing prevalence of hospital and community-acquired infections caused by multidrug-resistant (MDR) bacterial pathogens is rapidly limiting the options for effective antibiotic therapy. Systematic studies on combinations of already available antibiotics that could provide an effective treatment against MDR bacteria are needed. We tested combinations of antibiotics that target one important physiological function (peptidoglycan synthesis) at several steps, and studied Enterobacteriaceae (Klebsiella pneumoniae and Escherichia coli) for which multidrug resistance associated with ESBL-producing plasmids has become a major problem. To measure the effectiveness of antibiotics alone and in combination, we used checkerboard assays, static antibiotic concentration time-kill assays, and an improved in-vitro kinetic model that simulates human pharmacokinetics of multiple simultaneously administered antibiotics. The target strains included an MDR K. pneumoniae isolate responsible for a recent major hospital outbreak. A double combination (fosfomycin and aztreonam) and a triple combination (fosfomycin, aztreonam and mecillinam) were both highly effective in reducing bacterial populations in all assays, including the in vitro kinetic model. These combinations were effective even though each of the MDR strains was resistant to aztreonam alone. Our results provide an initial validation of the potential usefulness of a combination of antibiotics targeting peptidoglycan synthesis in the treatment of MDR Gram-negative bacteria. We suggest that a combination of fosfomycin with aztreonam could become a useful treatment option for such infections and should be further studied.

Tripping for tests: psychostimulant misuse among university students - extra

Throughout my years so far of medical school, caffeine has supplied that extra energy needed to get me through the late nights before deadlines and exams. There is also another well-recognised group of students, well-recognised at least in the USA - those who illegitimately acquire drugs, such as Adderall, in the run up to, and even during, exams. A study published in the Journal of Attention Disorders identified that 56% of student patients with attention-deficit hyperactivity disorder (ADHD) had been approached by other students to acquire their ADHD medications; just under half of these ADHD patients complied. Of course, these stimulants can also be obtained with a simple internet search of symptoms to then present to the physician. Evidence demonstrates that these drugs can significantly bolster the score of an exam and so we ask, is it wrong for students to use these drugs for enhancing their grade?

Bilateral retinal vasculitis in a patient with systemic lupus erythematosus and its remission with rituximab therapy

Severe retinal vasculitis is a rare, but potentially blinding, complication of patients with systemic lupus erythematosus (SLE). We describe here the first reported case of treating severe bilateral SLE-associated retinal vasculitis with the anti-CD20 monoclonal antibody rituximab, a drug which has established its role in rheumatoid arthritis and has shown promise in case series for the treatment of severe SLE that is unresponsive to other therapies. This case suggests that rituximab-induced B-cell depletion may provide an important new therapeutic option for refractory cases of this devastating ocular complication.