Advanced multiparametric magnetic resonance imaging of multinodular and vacuolating neuronal tumor

BACKGROUND AND PURPOSE

Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a rare brain lesion with suggestive imaging features. The aim of our study was to report the largest series of MVNTs so far and to evaluate the utility of advanced multiparametric magnetic resonance (MR) techniques.

METHODS

This multicenter retrospective study was approved by our institutional research ethics board. From July 2014 to May 2019, two radiologists read in consensus the MR examinations of patients presenting with a lesion suggestive of an MVNT. They analyzed the lesions' MR characteristics on structural images and advanced multiparametric MR imaging.

RESULTS

A total of 64 patients (29 women and 35 men, mean age 44.2 ± 15.1 years) from 25 centers were included. Lesions were all hyperintense on fluid-attenuated inversion recovery and T2-weighted imaging without post-contrast enhancement. The median relative apparent diffusion coefficient on diffusion-weighted imaging was 1.13 [interquartile range (IQR), 0.2]. Perfusion-weighted imaging showed no increase in perfusion, with a relative cerebral blood volume of 1.02 (IQR, 0.05) and a relative cerebral blood flow of 1.01 (IQR, 0.08). MR spectroscopy showed no abnormal peaks. Median follow-up was 2 (IQR, 1.2) years, without any changes in size.

CONCLUSIONS

A comprehensive characterization protocol including advanced multiparametric magnetic resonance imaging sequences showed no imaging patterns suggestive of malignancy in MVNTs. It might be useful to better characterize MVNTs.

Multinodular and Vacuolating Posterior Fossa Lesions of Unknown Significance

Multinodular and vacuolating neuronal tumor of the cerebrum is a rare supratentorial brain tumor described for the first time in 2013. Here, we report 11 cases of infratentorial lesions showing similar striking imaging features consisting of a cluster of low T1-weighted imaging and high T2-FLAIR signal intensity nodules, which we referred to as multinodular and vacuolating posterior fossa lesions of unknown significance. No relationship was found between the location of the lesion and clinical symptoms. A T2-FLAIR hypointense central dot sign was present in images of 9/11 (82%) patients. Cortical involvement was present in 2/11 (18%) of patients. Only 1 nodule of 1 multinodular and vacuolating posterior fossa lesion of unknown significance showed enhancement on postcontrast T1WI. DWI, SWI, MRS, and PWI showed no malignant pattern. Lesions did not change in size or signal during a median follow-up of 3 years, suggesting that multinodular and vacuolating posterior fossa lesions of unknown significance are benign malformative lesions that do not require surgical intervention or removal.

[Presentation of an assessment battery for visual mental imagery and visual perception]

INTRODUCTION

The relationship between visual perception and visual mental imagery are at the center of a lively theoretical debate between those postulating common neurocognitive processes between perception and imagery and those who emphasize the differences between these two entities. Neuropsychology can make an important contribution to this debate, by assessing associations and dissociations between perceptual and imaginal deficits in patients with brain damage. However, currently there is no standardized test battery available for such assessments.

MATERIAL AND METHODS

Here we present a battery of paper-and-pencil tests assessing different domains of visual mental imagery and visual perception abilities: object form and color, animals, orthographic material, numbers, faces, and space. We also explored the effects of age, educational level and gender on performance on a group of 103 participants free of neurological damage.

RESULTS

The battery includes two parts: one composed of 14 tests assessing mental imagery and the second part composed of eight tests assessing the abilities of visual perception. We calculated the correlations between the tests, and found that, with the exception of orthographic material, there were generally poor correlations between imagery and perceptual tests.

CONCLUSION

This result seems inconsistent with hypotheses postulating a strict correspondence between perceptual and imagery abilities.

Atteintes du système nerveux central et infection par le VIH-1

Central nervous system complications are common in HIV-1 infected patients and occur either as a result of concomitant immunosuppression (opportunistic infections, lymphoma and tumors), as a primary manifestation of HIV infection, or as an adverse effect of therapy (immune restoration and toxicity). These complications contribute largely to patient morbidity and mortality. In the era of highly active antiretroviral therapy (HAART) these disease states have changed in presentation, outcome and incidence. We review in detail the epidemiology, pathogenesis, clinical features, diagnosis, and management of these disorders.

[Sub-cortico-frontal encephalopathy and choreic movements related to recombinant interferon-alpha 2b]

Interferon (IFN)-alpha is associated with central nervous system (CNS) side effects such as depression and suicide ideation, somnolence, confusion, drowsiness, psychomotor slowing, memory impairment and visual disorientation. More severe complications are uncommon and include frank paranoia, dementia, coma, seizures and neuropathy. With the increasing long-term and extensive use of interferon (IFN)-alpha several new neurologic adverse effects have been recognized. We report on two patients who developed severe subcortico-frontal impairment, associated in one case with choreic movements, after a long-term treatment with IFN-alpha 2b for hematologic malignancies. Our patients rapidly and completely recovered from their cognitive and motor symptoms after the discontinuation of the drug. The same neurologic symptoms reappeared when we attempted to reintroduce lower doses of IFN-alpha in one case. Although little is known regarding IFN-alpha actions in the CNS, several possible mechanisms may underlie its neurotoxicity and might result from complex direct and indirect effects involving brain vasculature, neuroendocrine system, neurotoxic secondary cytokines'release and neurotransmitters.

Reversible ALS-like disorder in HIV infection

OBJECTIVE

To describe the clinical features, treatment, and outcome of six cases of HIV-1-associated ALS-like disorder.

METHODS

The authors reviewed patients with HIV infection with neurologic symptoms seen over a 13-year period. Patients were identified by using the El Escorial research diagnostic criteria defining three categories of certainty for definite, probable, or possible ALS. Clinical features, EMG, CSF, serum analyses, and imaging and virological studies were assessed.

RESULTS

Six patients with immunodepression (mean CD4(+) cells = 86.2/mm(3); mean age = 34 years) developed distal motor weakness mimicking a monomelic amyotrophy that subacutely progressed regionally or assumed a symmetric distribution on more than one region. EMG was characteristic of motor neuron disease with no multifocal conduction block. Causes other than HIV-1 were ruled out. The unusual rapid extension of the disease and the positive response to antiretroviral therapy suggest that ALS syndrome and HIV infection are etiologically related. HIV-1 might cause an ALS-like disorder by several mechanisms-via neuronal infection, by secretion of toxic viral substance, by inducing the immune system to secrete cytokines, or by inducing an autoimmune disease.

CONCLUSION

These cases suggest that the association between some motor neuron diseases and HIV infection is not coincidental but pathogenetically related and that ALS-like disorder should be considered an HIV-related neurologic complication.

[Susac's syndrome: improvement with combined cyclophosphamide and intravenous immunoglobulin therapy]

We report a case of Susac's syndrome characterized by subacute encephalopathy, bilateral hearing loss and multiple bilateral branch retinal artery occlusions in a forty-year-old-white-woman. Brain Magnetic Resonance Imaging showed on T2-weighted images multiple, punctate areas of increased signal intensity in periventricular white matter, gray matter and brainstem most of them being enhanced by gadolinium. Cerebrospinal fluid was acellular but with an increased protein level (1.66 g/l). Treatment with cyclophosphamid and intravenous immmunoglobulin resulted in dramatic improvement of the clinical status over the following months and CSF normalization.

Facial diplegia complicating a bilateral internal carotid artery dissection

BACKGROUND AND PURPOSE

We report a case of facial diplegia complicating a bilateral internal carotid artery dissection.

CASE DESCRIPTION

A 49-year-old patient presented with unilateral headache and oculosympathetic paresis. Cerebral angiography revealed a bilateral internal carotid artery dissection. A few days later, the patient developed a facial diplegia that regressed after arterial recanalization. An arterial anatomic variation may explain this ischemic complication of carotid dissection.

CONCLUSIONS

Double carotid dissection should be included among the causes of bilateral seventh nerve palsy.

Neuropathy in diffuse infiltrative lymphocytosis syndrome: an HIV neuropathy, not a lymphoma

OBJECTIVE

To determine whether CD8 lymphoid infiltrates in nerves of patients with HIV-associated diffuse infiltrative lymphocytosis syndrome (DILS) corresponds to a lymphomatous neoplastic process or to a proliferation of T cells reactional to HIV.

BACKGROUND

DILS is characterized by persistent CD8 hyperlymphocytosis and multivisceral CD8 T-cell infiltration, which may affect peripheral nerves.

METHODS

Presence of monoclonal T cells and HIV-1 proviral load were evaluated by polymerase chain reaction (PCR) techniques in frozen peripheral nerve samples from six patients with DILS neuropathy and 22 patients with other HIV-associated peripheral neuropathies, including mononeuritis multiplex (MM:6), inflammatory demyelinating polyneuropathies (IDP:6), distal sensory polyneuropathy (DSP:5), and toxic distal sensory polyneuropathy (TDSP:5).

RESULTS

Five of six patients with DILS showed no detectable monoclonal T-cell clones in their nerves. Nerve proviral load in DILS (6.8 +/- 0.2 log/10(5) cells) was much higher than in MM (p < 0.008), IDP (p < 0.001), DSP (p < 0.001), and TDSP (p < 0.005).

CONCLUSIONS

DILS neuropathy represents a separate entity among HIV-associated neuropathies. It is associated with massive HIV proviral load in nerve and must not be confused with a peripheral nerve T-cell lymphoma.

Peripheral neuropathy in human immunodeficiency virus-infected patients with the diffuse infiltrative lymphocytosis syndrome

A subset of human immunodeficiency virus (HIV)-infected patients develop persistent CD8 hyperlymphocytosis and a Sjogren's syndrome-like syndrome associated with multivisceral CD8 T-cell infiltration, known as the diffuse infiltrative lymphocytosis syndrome (DILS). Patients with DILS tend to have higher CD4 cell counts, fewer opportunistic infections, and longer survival times than other HIV-infected patients. Peripheral nerve involvement in DILS has been poorly documented. We studied 12 HIV-infected patients with CD8 hyperlymphocytosis, DILS, and clinical signs of peripheral neuropathy. Two of 4 patients who were HLA typed were HLA-DR5 and 1 was HLA-DR6. All patients had the sicca syndrome and multivisceral involvement. The neuropathy was acute or subacute, always painful, and symmetrical in 8 cases. Electrophysiology was consistent with axonal neuropathy in 10 of 12 patients. Nerve biopsy showed marked angiocentric CD8 infiltrates without mural necrosis (12 of 12), and abundant expression of HIV p24 protein in macrophages (12 of 12). The HIV genome was detected by polymerase chain reaction in nerve homogenates. Zidovudine therapy was associated with improvement in 6 of 6 patients and steroid therapy was beneficial in 4 of 5 patients. No T-cell lymphoma was observed during follow-up, but 2 patients developed a primary B-cell lymphoma. We conclude that DILS neuropathy represents HIV-associated neuropathy, characterized by marked CD8 infiltration and abundant HIV in nerve, that improves with zidovudine or steroid therapy, and probably reflects a systemic host-determined and antigen-driven response to HIV.

[Nervous system lesions due to cytomegalovirus in AIDS]

Viral infections are observed with increasing frequency in HIV patients and one of the commonest viruses is cytomegalovirus. Clinical features of cytomegalovirus (CMV) encephalitis are non specific and radiology is rarely helpful. Polymerase chain reaction in cerebrospinal fluid has been shown to be useful for diagnosis of CMV encephalitis. CMV lesions in the nervous system are subdivided into six groups: Nodular encephalitis, myeloradiculitis, isolated inclusion-bearing cells, focal parenchymal necrosis, ventriculo-encephalitis and peripheral neuropathy. Clinicopathological aspects are only subdivided into four groups: Encephalitis, myelitis, myeloradiculitis and polyneuropathy. Diagnosis of cytomegalovirus encephalitis should be considered in patients with a CD4 count less than 100 cells/mm3. Recent developments in diagnostic techniques allow early recognition and more aggressive therapeutic approaches.

AIDS-associated cytomegalovirus infection mimicking central nervous system tumors: a diagnostic challenge

We reviewed cases of cytomegalovirus (CMV) infection of the central nervous system (CNS) that initially masqueraded as tumors in 37 of 543 consecutive patients infected with human immunodeficiency virus (HIV) and CMV who were seen at the Pasteur Institute Hospital and Saint-Louis Hospital (Paris) between 1992 and 1994. We detail the clinical features of three patients who presented with ring-enhanced space-occupying lesions mimicking CNS tumors. They were all profoundly immunodepressed (mean CD4 cell count, 13/mm3). Magnetic resonance imaging (MRI) showed enlargement of the spinal cord in one case, consistent with a space-occupying lesion and showing gadolinium enhancement; in the other two cases, ring-enhanced mass lesions were seen in the cerebral hemispheres. In all three cases marked edema and a mass effect were present. Image-guided stereotactic biopsies confirmed the diagnosis of CMV infection. The three patients' conditions improved with specific therapy. MRI showed enhanced focal intraparenchymal lesions consistent with marked focal necrosis, probably related to the severity of immunodepression, as HIV infection had been diagnosed several years previously. CMV infection should be considered as a cause of ring-enhanced space-occupying mass lesions in patients with HIV-1 infection. Earlier identification of these unusual tumorlike forms of CMV infection by means of MRI should result in improved outcome.

AIDS-associated progressive multifocal leukoencephalopathy revealed by new-onset seizures

PURPOSE

To describe the clinical features of new-onset seizures in HIV-1-infected persons with progressive multifocal leukoencephalopathy (PML), and to discuss potential mechanisms.

PATIENTS AND METHODS

Forty-nine consecutive HIV-1-infected patients with PML attended our institutions between January 1988 and September 1993. We retrospectively analyzed cases with seizures as the presenting symptom of PML.

RESULTS

Twenty percent of the HIV-1-infected patients with PML presented with new-onset seizures of various types, generalized or partial. None of them met the criteria of the AIDS dementia complex or had a concomitant opportunistic infection. Their mean CD4 cell count was < 60/mm3. Brain magnetic resonance imaging showed areas of increased signal intensity on T2-weighted images in 9 cases, and atrophy in only 1 case. Lesions most often involved subcortical white matter in parieto-occipital or frontal lobes, but 2 patients had posterior fossa lesions. Image-guided stereotactic brain biopsies in 8 cases and postmortem examination in 2 confirmed the diagnosis of PML. Typical histological lesions were observed in all cases, and positive immunolabelling of oligodendroglial nuclei was obtained in all cases with the polyclonal antibody directed against late SV40 antigens. Putative causative factors for the seizures include demyelinated lesions adjacent to the cerebral cortex acting as irritative foci, axonal conduction abnormalities, or disturbances of the neuron-glia balance.

CONCLUSION

These cases illustrate that PML should be considered as a possible cause of new-onset seizures in patients with HIV-1 infection.

Brain stem encephalitis due to varicella-zoster virus in a patient with AIDS

We describe a patient infected with human immunodeficiency virus (HIV) who had localized brain stem encephalitis due to varicella-zoster virus (VZV) and no cutaneous eruption. Diagnosis of the infection was based on the presence of Cowdry type A intranuclear inclusions in neurons, astrocytes, and oligodendrocytes positive for VZV (as shown by immunochemical staining). Although this infection is rare, we demonstrate the need for clinicians to include VZV infection in the differential diagnosis of rapidly progressive multiple cranial nerve palsies in HIV-infected patients, particularly because specific treatment for VZV infection is effective and relatively safe.

[Isoform 4 of apolipoprotein E and Alzheimer disease. Specificity and clinical study]

We studied apolipoprotein E (apoE) phenotype in 113 patients with possible and probable Alzheimer's disease (AD), 49 patients with Parkinson's disease (including 11 patients with dementia) and 23 patients with mixed and vascular dementia. Normal controls were 498 young, healthy blood donors previously recorded. All patients were assayed for blood lipid parameters. All AD patients underwent a neuropsychological evaluation (including a mini-mental status and 5 subtests of Cole and Dastoor hierarchic dementia scale) and a detailed interrogation of them and their caregivers about their familial and personal medical history. The recorded data included age at onset, clinical subtype (i.e. amnesic or aphaso-apraxic), occurrence of fits, cases of probable dementia in relatives, and ages of their parents at death. There was a significant association between the fourth isoform of apoE and AD, as in previous works. We did not found such an association for PD patients (even with dementia) nor mixed and vascular demented patients. We failed to find any association between any clinical characteristic of the patients and the biological subgroups defined by the number of epsilon 4 alleles, except with regard for the age of onset. Surprisingly, the mothers of epsilon 4 bearers had a significantly longer life than mothers of other patients. We failed to found any significant difference of apoE2 isoform frequency between AD patients and controls. AD patients had higher levels of cholesterol and apoAl than did MP and mixed and vascular demented patients. ApoAl level is known to constitute a protective factor against coronary heart disease, which is usually increased by the presence of apoE-epsilon 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral glial tumors and human immunodeficiency virus-1 infection. More than a coincidental association

BACKGROUND

The authors describe the clinical and morphologic patterns in four patients with acquired immune deficiency syndrome (AIDS) who developed intracranial glial tumors.

METHODS

This retrospective study reports 70 patients at various stages of human immunodeficiency virus-1 (HIV-1) infection who underwent stereotactic brain biopsy for an intracerebral space-occupying lesion.

RESULTS

Of these patients, four had glial tumors: one astroblastoma, two astrocytomas, and one glioblastoma. Glial tumors probably arise from a complex interplay of factors; possibilities include the activation of a dominant oncogene or viral inactivation of a tumor suppressor gene by a viral promoter (like the tat protein), impairment of immune defenses (which facilitates the growth of astrocytomas in acute lymphoblastic leukemia), production of cellular growth factors, cytokines, possible infection of glial cells by HIV, and the potentiation of a coinfectious agent.

CONCLUSIONS

These cases illustrate that glial tumors should be considered in the differential diagnosis of brain masses in HIV-1 infection, especially because specific treatment for these tumors is available. Moreover, the occurrence of glial tumors in AIDS patients is not only an important event from a clinical point of view, but may also have implications for the pathogenesis of tumors in AIDS.

[Specialized memory consultation. Value and evaluation after 2 years of functioning]

Disorders of memory are a frequent cause of consultation and are observed in dementias, in some depressive syndromes and in normal ageing. The specialized memory consultation is based on two successive examinations: one by a neurologist, the other by a psychologist, using standardized batteries of tests. In 100 consecutive subjects, 3 main groups of about 20 to 30 individuals each could be identified: dementia syndromes, psychiatric disorders and age-related disorders of memory. The remaining subjects had various diseases. In subjects with memory complaints a psychometric evaluation performed by a team of specialists seems to be the only means of refining the diagnosis enough for a personalized management. In addition, the specialized consultation team acquires the knowledge that will help it, in the future, to lay down the bases of medical prevention of pathological cerebral ageing.

[Cerebral glioblastoma: a new complication of HIV-1 infection]

A new case of supratentorial malignant glioma is reported in an HIV-1 infected male homosexual. Tumours of the nervous system account for only 5 to 10 percent of neurological complications of AIDS, and most of them are lymphomas or metastases from Kaposi's sarcomas. In fact, HIV-1 is a neurotropic lentivirus, not transforming by definition. Our patient had a frontal tumoral syndrome resistant to the conventional anti-toxoplasmic treatment. Pathological examination of a tumoral fragment obtained by stereotactic biopsy showed that according to the WHO criteria the tumour was a glioblastoma. The mechanism through which HIV infection results in malignant transformation of astrocytes is conjectural. There is no consensus on whether the virus is located in glial cells, but the transgenic animal technique suggests that the tat gene might play a certain role. Other hypotheses concerning the indirect neurotoxicity of HIV have been put forward, notably that of viral coinfection with viruses of the papova group.

[Meningoradiculitis after injection of an antirabies vaccine. A vaccine from human diploid cell culture]

We report the case of a 45-year old farmer who developed meningoradiculitis after preventive anti-rabies vaccination with a vaccine obtained from human diploid cell culture. Two weeks after the second injection of vaccine, the patient complained of sensory symptoms in the right half of his body. These symptoms spontaneously regressed. The literature is reviewed and the physiopathological hypotheses are discussed.