Systemic relapses of primary CNS lymphomas (PCNSL): a LOC network study.

Primary central nervous system lymphomas (PCNSLs) classically remain confined within the CNS throughout their evolution for unknown reasons. Our objective was to analyse the rare extracerebral relapses of PCNSL in a nationwide population-based study. We retrospectively selected PCNSL patients who experienced extracerebral relapse during their follow-up from the French LOC database. Of the 1968 PCNSL included in the database from 2011, 30 (1.5%, median age 71 years, median KPS 70) presented an extracerebral relapse, either pure (n = 20) or mixed (both extracerebral and in the CNS) (n = 10), with a histological confirmation in 20 cases. The median delay between initial diagnosis and systemic relapse was 15.5 months [2-121 months]. We found visceral (n = 23, 77%), including testis in 5 (28%) men and breast in 3 (27%) women, lymph node (n = 12, 40%), and peripheral nervous system (PNS) (n = 7, 23%) involvement. Twenty-seven patients were treated with chemotherapy, either with only systemic targets (n = 7) or mixed systemic and CNS targets (n = 20), 4 were consolidated by HCT-ASCT. After systemic relapse, the median progression-free survival and overall survival (OS) were 7 and 12 months, respectively. KPS > 70 and pure systemic relapses were significantly associated with higher OS. Extracerebral PCNSL relapses are rare, mainly extranodal, and frequently involve the testis, breast, and PNS. The prognosis was worse in mixed relapses. Early relapses raise the question of misdiagnosed occult extracerebral lymphoma at diagnostic workup that should systematically include a PET-CT. Paired tumour analysis at diagnosis/relapse would provide a better understanding of the underlying molecular mechanisms.

Dopamine denervation in the functional territories of the striatum: a new MR and atlas-based 123I-FP-CIT SPECT quantification method.

Current quantification methods of 123I-FP-CIT SPECT rely on anatomical parcellation of the striatum. We propose here to implement a new method based on MRI segmentation and functional atlas of the basal ganglia (MR-ATLAS) that could provide a reliable quantification within the sensorimotor, associative, and limbic territories of the striatum. Patients with Parkinson's disease (PD), idiopathic rapid eye movement sleep behavioral disorder (iRBD), and healthy controls underwent 123I-FP-CIT SPECT, MRI, motor, and cognitive assessments. SPECT data were corrected for partial volume effects and registered to a functional atlas of the striatum to allow quantification in every functional region of the striatum (nucleus accumbens, limbic, associative, and sensorimotor parts of the striatum). The MR-ATLAS quantification method is proved to be reliable in every territory of the striatum. In addition, good correlations were found between cognitive dysexecutive tests and the binding within the functional (limbic) territories of the striatum using the MR-ATLAS method, slightly better than correlations found using the anatomical quantification method. This new MR-ATLAS method provides a robust and useful tool for studying the dopaminergic system in PD, particularly with respect to cognitive functions. It may also be relevant to further unravel the relationship between dopaminergic denervation and cognitive or behavioral symptoms.

Can FDG-PET/MR help to overcome limitations of sequential MRI and PET-FDG for differential diagnosis between recurrence/progression and radionecrosis of high-grade gliomas?

The aim of our study was assessing the potential of FDG-PET-MRI to overcome limitations of separately performed MRI and PET-FDG and improving the performance of high-grade gliomas evaluation. Combined PET-MRI analysis allowed differentiating between recurrence/progression and radionecrosis with improved diagnostic accuracy (95% vs 63% for PET and 82% for MRI). FDG being a reliable, cost-saving tracer in this indication, combined FDG PET-MRI analysis could play a significant role in the follow-up of high-grade brain tumors.

Multimodal neurometabolic investigation of the effects of zolpidem on leukoencephalopathy-related apathy.

BACKGROUND AND PURPOSE: The symptomatic effect of zolpidem on apathy has been reported in neurological disorders such as strokes and post-anoxic brain injuries, but not in white-matter disease of the brain. METHODS: A 38-year-old patient presenting with severe apathy related to a genetic leukoencephalopathy but showing marked improvement of apathy after taking 10 mg of zolpidem was studied. To understand what may mediate such a clinical effect, a multimodal neurometabolic approach using 18 F fluorodeoxyglucose positron emission tomography (FDG-PET) and a dedicated magnetic resonance spectroscopy (MRS) sequence for gamma aminobutyric acid (GABA) and glutamine + glutamate metabolism was undertaken. RESULTS: Pre-zolpidem FDG-PET showed hypometabolism in the orbitofrontal cortex, dorsolateral cortex and basal ganglia compared to healthy controls. Post-zolpidem, FDG-PET displayed increased metabolism in the orbitofrontal cortex together with improvement in the emotional and auto-activation domains of apathy. There was no improvement in the cognitive domain of apathy, and no change in metabolism in the dorsolateral frontal cortex. Post-zolpidem, MRS showed increased GABA and glutamine + glutamate levels in the frontal cortex and pallidum. CONCLUSION: Our multimodal neurometabolic study suggests that the effects of zolpidem on apathy are related to increased metabolism in the orbitofrontal cortex and basal ganglia secondary to GABA modulation. Zolpidem may improve apathy in other white-matter disorders.

COVID-19-related encephalopathy: a case series with brain FDG-positron-emission tomography/computed tomography findings.

AIM: The aim of this paper is to describe the clinical features of COVID-19-related encephalopathy and their metabolic correlates using brain 2-desoxy-2-fluoro-D-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) imaging. BACKGROUND AND PURPOSE: A variety of neurological manifestations have been reported in association with COVID-19. COVID-19-related encephalopathy has seldom been reported and studied. METHODS: We report four cases of COVID-19-related encephalopathy. The diagnosis was made in patients with confirmed COVID-19 who presented with new-onset cognitive disturbances, central focal neurological signs, or seizures. All patients underwent cognitive screening, brain magnetic resonance imaging (MRI), lumbar puncture, and brain 2-desoxy-2-fluoro-D-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) (FDG-PET/CT). RESULTS: The four patients were aged 60 years or older, and presented with various degrees of cognitive impairment, with predominant frontal lobe impairment. Two patients presented with cerebellar syndrome, one patient had myoclonus, one had psychiatric manifestations, and one had status epilepticus. The delay between first COVID-19 symptoms and onset of neurological symptoms was between 0 and 12 days. None of the patients had MRI features of encephalitis nor significant cerebrospinal fluid (CSF) abnormalities. SARS-CoV-2 RT-PCR in the CSF was negative for all patients. All patients presented with a consistent brain FDG-PET/CT pattern of abnormalities, namely frontal hypometabolism and cerebellar hypermetabolism. All patients improved after immunotherapy. CONCLUSIONS: Despite varied clinical presentations, all patients presented with a consistent FDG-PET pattern, which may reflect an immune mechanism.

Prognosis of glioblastoma patients improves significantly over time interrogating historical controls.

BACKGROUND: Glioblastoma (GBM) is the most common devastating primary brain cancer in adults. In our clinical practice, median overall survival (mOS) of GBM patients seems increasing over time. METHODS: To address this observation, we have retrospectively analyzed the prognosis of 722 newly diagnosed GBM patients, aged below 70, in good clinical conditions (i.e. Karnofsky Performance Status -KPS- above 70%) and treated in our department according to the standard of care (SOC) between 2005 and 2018. Patients were divided into two groups according to the year of diagnosis (group 1: from 2005 to 2012; group 2: from 2013 to 2018). RESULTS: Characteristics of patients and tumors of both groups were very similar regarding confounding factors (age, KPS, MGMT promoter methylation status and treatments). Follow-up time was fixed at 24 months to ensure comparable survival times between both groups. Group 1 patients had a mOS of 19 months ([17.3-21.3]) while mOS of group 2 patients was not reached. The recent period of diagnosis was significantly associated with a longer mOS in univariate analysis (HR=0.64, 95% CI [0.51 - 0.81]), p < 0.001). Multivariate Cox analysis showed that the period of diagnosis remained significantly prognostic after adjustment on confounding factors (adjusted Hazard Ratio (aHR) 0.49, 95% CI [0.36-0.67], p < 0.001). CONCLUSION: This increase of mOS over time in newly diagnosed GBM patients could be explained by better management of potentially associated non-neurological diseases, optimization of validated SOC, better management of treatments side effects, supportive care and participation in clinical trials.

Are Gadolinium-Enhanced MR Sequences Needed in Simultaneous 18F-FDG-PET/MRI for Tumor Delineation in Head and Neck Cancer?

BACKGROUND AND PURPOSE: PET/MRI with 18F-FDG has demonstrated the advantages of simultaneous PET and MR imaging in head and neck cancer imaging, MRI allowing excellent soft-tissue contrast, while PET provides metabolic information. The aim of this study was to evaluate the added value of gadolinium contrast-enhanced sequences in the tumor delineation of head and neck cancers on 18F-FDG-PET/MR imaging. MATERIALS AND METHODS: Consecutive patients who underwent simultaneous head and neck 18F-FDG-PET/MR imaging staging or restaging followed by surgery were retrospectively included. Local tumor invasion and lymph node extension were assessed in 45 head and neck anatomic regions using 18F-FDG-PET/MR imaging by 2 rater groups (each one including a radiologist and a nuclear medicine physician). Two reading sessions were performed, one without contrast-enhanced sequences (using only T1WI, T2WI, and PET images) and a second with additional T1WI postcontrast sequences. The results were compared with the detailed histopathologic analysis, used as reference standard. The κ concordance coefficient between the reading sessions and sensitivity and specificity for each region were calculated. RESULTS: Thirty patients were included. There was excellent agreement between the contrast-free and postgadolinium reading sessions in delineating precise tumor extension in the 45 anatomic regions studied (Cohen κ = 0.96, 95% CI = [0.94-0.97], P < .001). The diagnostic accuracy did not differ between contrast-free and postgadolinium reading sessions, being 0.97 for both groups and both reading sessions. For the 2 rater groups, there was good sensitivity for both contrast-free (0.83 and 0.85) and postgadolinium reading sessions (0.88 and 0.90, respectively). Moreover, there was excellent specificity (0.98) for both groups and reading sessions. CONCLUSIONS: Gadolinium chelate contrast administration showed no added value for accurate characterization of head and neck primary tumor extension and could possibly be avoided in the PET/MR imaging head and neck workflow.

[Semantic dementia associated with amyotrophic lateral sclerosis]. / Démence sémantique associée à une sclérose latérale amyotrophique.

The association semantic dementia-amyotrophic lateral sclerosis has been rarely reported in the literature. We report a case study of a patient with a severe prosopagnosia in relation with semantic dementia associated, 12 months later, with a motor neuron disease.

[Pituitary germinoma presenting as a pseudotumoral lymphocytic hypophysitis in a man]. / Germinome hypophysaire révélé par une hypophysite lymphocytaire pseudo-tumorale chez un homme.

A 45-year-old man presented with headaches and extraocular muscle palsy due to a sellar mass extending into the right cavernous sinus. Hormonal determinations revealed a gonadotrophic insufficiency. A transsphenoidal surgical removal revealed a lymphocytic hypophysitis with fibrosis and necrosis. Rapid growth of the pseudotumor was noted despite a high dose steroid therapy (1 mg/kg/d) for a month. Further biological and histopathological investigations were performed. They showed a high cerebrospinal fluid (CSF) B-human chorionic gonadotropin (ss-HCG) level of 12 UI/L (normal<5 UI/L), normal plasma BHCG level, and undetectable CSF and plasma alpha-fetoprotein levels. The tumors cells showed a positive reactivity for placental alkaline phosphatase and for vimentin. These findings were consistent with an inflammatory lymphocytic process caused by an intrasellar germinoma. Chemotherapy was ill-tolerated and external radiotherapy was ineffective.

Hypervariability, suppressed recombination and the genetics of individuality.

We define 'genetic individuality' as intraspecies variation that has substantial heritability and involves traits that are sufficiently common that they can be observed in any modest-sized sampling of individuals. We propose that genetic individuality is largely shaped by the combinatory shuffling of a modest number of genes, each of which exists as a family of functionally and structurally diverged alleles. Unequivocal examples of such allele families are found at the O-antigen-biosynthetic locus in Pseudomonas aeruginosa and the human leucocyte antigen locus in humans. We examine characteristic features of these allele families and explore the possibility that genetic loci with similar characteristics can be recognized in a whole-genome scan of human genetic variation.

A genomic sequence analysis of the mouse and human microtubule-associated protein tau.

Microtubule associated protein tau (MAPT) encodes the microtubule associated protein tau, the primary component of neurofibrillary tangles found in Alzheimer's disease and other neurodegenerative disorders. Mutations in the coding and intronic sequences of MAPT cause autosomal dominant frontotemporal dementia (FTDP-17). MAPT is also a candidate gene for progressive supranuclear palsy and hereditary dysphagic dementia. A human PAC (201 kb) and a mouse BAC (161 kb) containing the entire MAPT and Mtapt genes, respectively, were identified and sequenced. Comparative DNA sequence analysis revealed over 100 conserved non-repeat potential cis-acting regulatory sequences in or close to MAPT. Those islands with greater than 67% nucleotide identity range in size from 20 to greater than 1700 nucleotides. Over 90 single nucleotide polymorphisms were identified in MAPT that are candidate susceptibility alleles for neurodegenerative disease. The 5' and 3' flanking genes for MAPT are the corticotrophin-releasing factor receptor (CRFR) gene and KIAA1267, a gene of unknown function expressed in brain.

Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen.

Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances.