Postoperative disappearance of leptomeningeal enhancement around the brainstem in glioblastoma.

PURPOSE: Leptomeningeal enhancement (LME) suggests leptomeningeal dissemination (LMD) of tumor cells, which is a complication of end-stage glioblastoma, and is associated with a poor prognosis. However, magnetic resonance imaging (MRI) occasionally indicates the disappearance of peri-brainstem LME after surgical resection of glioblastoma. Since preoperative LMD may affect treatment indications, we aimed to analyze the clinical significance of preoperative LME of the brainstem in glioblastoma. METHODS: We retrospectively collected clinical and radiological data from consecutive patients with glioblastoma and preoperative LME of the brainstem, who were treated at our hospital between 2017 and 2020. RESULTS: Among 112 patients with glioblastoma, nine (8%) showed preoperative LME of the brainstem. In comparison with tumors without LME, tumor size was significantly associated with the preoperative LME of the brainstem (p = 0.016). In addition, there was a trend toward significance for a relationship between deep tumor location and preoperative LME of the brainstem (p = 0.058). Notably, among six patients who underwent surgical resection for glioblastoma with LME of the brainstem, four showed significant radiological disappearance of the LME on postoperative MRI. This suggests that the LME did not result from LMD in these cases. Moreover, these four patients lived longer than would be expected from the presence of LMD. However, this LME disappearance was not observed after biopsy or chemoradiotherapy. CONCLUSIONS: These findings suggest that preoperative LME does not necessarily indicate the presence of untreatable LMD; moreover, LME may disappear after surgical tumor resection. Thus, transient preoperative LME could be attributed to other mechanisms, including impaired venous flow due to intratumoral arteriovenous shunts, which can be resolved by reducing the tumor burden.

Rheumatoid meningitis: a case series report and review of modern therapeutic schemes and outcome.

INTRODUCTION: Rheumatoid meningitis (RM) is an extremely rare extra-articular complication of rheumatoid arthritis (RA), with approximately 165 cases reported world-wide. RM exhibits a broad range of symptoms, with stroke-like episodes and seizures being the most common manifestations. The primary differential diagnoses include vascular and infectious diseases. The influence of immunomodulatory medications on the pathophysiology of RM remains unclear. There are no consensus guidelines on therapeutic regimen. METHODS: We present four patients with prior history of RA that developed different neurological syndromes in correlation to radiological leptomeningitis. Clinical presentations, comorbid conditions, supplementary diagnostic assessments, treatments, and prognosis are provided. A literature review of recent immunosuppressive management in RM patients was performed. RESULTS: Three patients presented to hospital with recurrent focal seizures. Only two suffered meningism, reporting headache and fever. Magnetic resonance imaging (MRI) showed different grades of leptomeningitis across all cases. Notably, three cases demonstrated bilateral involvement extending to the pachymeninges. Two patients exhibited pronounced CSF mononuclear inflammation while extended microbiological evaluations yielded negative results. Two patients required biopsy for confirmation. The initiation of immunosuppressive therapy marked a turning point for three patients who previously exhibited progressive deterioration. Mortality was absent in all cases. CONCLUSIONS: Our experience remarks the elusive nature of RM. Rigorous exclusionary diagnostics are imperative to differentiate RM from mimicking conditions. Clinical manifestations oscillate between transient episodes and progressive neurological impairments, punctuated by frequent epileptic seizures. In scenarios where clinical worsening persists or where clinical and radiological evaluations are inconclusive, aggressive immunosuppressive therapy is recommended.

Association of MRI leptomeningeal enhancement with disability worsening in progressive multiple sclerosis: A clinical and post-mortem study.

BACKGROUND: Leptomeningeal enhancement (LME) has been described as a biomarker of meningeal inflammation in multiple sclerosis (MS). OBJECTIVE: The aim of this study was to (1) assess if LME is predictive of disability worsening in progressive MS (pMS) patients and (2) investigate the pathological substrates of LME in an independent post-mortem MS series. METHODS: In total, 115 pMS patients were imaged yearly with 1.5T MRI, using post-contrast CUBE 3D FLAIR for LME detection. Endpoint: to identify the baseline variables predictive of confirmed disability worsening (CDW) at 24 months follow-up. Post-mortem, inflammation, and structural changes of the leptomeninges were assessed in 12 MS/8 control brains. RESULTS: LME (27% of patients at baseline) was associated with higher EDSS and lower brain volume (nBV). LME was unchanged in most patients over follow-up. LME at baseline MRI was independently associated with higher risk of 24 months CDW (HR 3.05, 95% CI 1.36-6.84, p = 0.007) in a Cox regression, including age, nBV, T2 lesion volume, high-efficacy treatments, and MRI disease activity. Post-mortem, focal structural changes (fibrosis) of the leptomeninges were observed in MS, usually associated with inflammation (Kendall's Tau 0.315, p < 0.0001). CONCLUSIONS: LME is frequently detected in pMS patients using 1.5T MRI and is independently predictive of disability progression. LME could result from both focal leptomeningeal post-inflammatory fibrosis and inflammation.

Leptomeningeal enhancement on post-contrast FLAIR images for early diagnosis of Susac syndrome.

BACKGROUND: Leptomeningeal enhancement (LME) is a key feature of Susac syndrome (SuS) but is only occasionally depicted on post-contrast T1-weighted images (T1-WI). OBJECTIVE: As post-contrast fluid-attenuated inversion recovery (FLAIR) may be more sensitive, our aim was to assess LME in SuS on this sequence. METHODS: From 2010 to 2020, 20 patients with definite SuS diagnosis were retrospectively enrolled in this multicentre study. Two radiologists independently assessed the number of LME on post-contrast FLAIR and T1-WI acquisitions performed before any treatment. A chi-square test was used to compare both sequences and the interrater agreement was calculated. RESULTS: Thirty-five magnetic resonance imagings (MRIs) were performed before treatment, including 19 post-contrast FLAIR images in 17 patients and 25 post-contrast T1-WI in 19 patients. In terms of patients, LME was observed on all post-contrast FLAIR, contrary to post-contrast T1-WI (17/17 (100%) vs. 15/19 (79%), p < 0.05). In terms of sequences, LME was observed on all post-contrast FLAIR, contrary to post-contrast T1-WI (19/19 (100%) vs. 16/25 (64%), p < 0.005). LME was disseminated at both supratentorial (19/19) and infratentorial (18/19) levels on post-contrast FLAIR, contrary to post-contrast T1-WI (3/25 and 9/25, respectively). Interrater agreement was excellent for post-contrast FLAIR (κ = 0.95) but only moderate for post-contrast T1-WI (κ = 0.61). CONCLUSION: LME was always observed and easily visible on post-contrast FLAIR images prior to SuS treatment. In association with other MRI features, it is highly indicative of SuS.

Association of retinal atrophy with cortical lesions and leptomeningeal enhancement in multiple sclerosis on 7T MRI.

BACKGROUND: Retinal atrophy in multiple sclerosis (MS) as measured by optical coherence tomography (OCT) correlates with demyelinating lesions and brain atrophy, but its relationship with cortical lesions (CLs) and meningeal inflammation is not well known. OBJECTIVES: To evaluate the relationship of retinal layer atrophy with leptomeningeal enhancement (LME) and CLs in MS as visualized on 7 Tesla (7T) magnetic resonance imaging (MRI). METHODS: Forty participants with MS underwent 7T MRI of the brain and OCT. Partial correlation and mixed-effects regression evaluated relationships between MRI and OCT findings. RESULTS: All participants had CLs and 32 (80%) participants had LME on post-contrast MRI. Ganglion cell/inner plexiform layer (GCIPL) thickness correlated with total CL volume (r =-0.45, p < 0.01). Participants with LME at baseline had thinner macular retinal nerve fiber layer (mRNFL; p = 0.01) and GCIPL (p < 0.01). Atrophy in various retinal layers was faster in those with certain patterns of LME. For example, mRNFL declined -1.113 (-1.974, -0.252) µm/year faster in those with spread/fill-pattern LME foci at baseline compared with those without (p = 0.01). CONCLUSION: This study associates MRI findings of LME and cortical pathology with thinning of retinal layers as measured by OCT, suggesting a common link between meningeal inflammation, CLs, and retinal atrophy in MS.

Cerebrospinal Fluid Features in Patients With Coronavirus Disease 2019 and Neurological Manifestations: Correlation with Brain Magnetic Resonance Imaging Findings in 58 Patients.

BACKGROUND: Neurological manifestations are common in patients with coronavirus disease 2019 (COVID-19), but little is known about pathophysiological mechanisms. In this single-center study, we examined neurological manifestations in 58 patients, including cerebrospinal fluid (CSF) analysis and neuroimaging findings. METHODS: The study included 58 patients with COVID-19 and neurological manifestations in whom severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction screening and on CSF analysis were performed. Clinical, laboratory, and brain magnetic resonance (MR) imaging data were retrospectively collected and analyzed. RESULTS: Patients were mostly men (66%), with a median age of 62 years. Encephalopathy was frequent (81%), followed by pyramidal dysfunction (16%), seizures (10%), and headaches (5%). CSF protein and albumin levels were increased in 38% and 23%, respectively. A total of 40% of patients displayed an elevated albumin quotient, suggesting impaired blood-brain barrier integrity. CSF-specific immunoglobulin G oligoclonal band was found in 5 patients (11%), suggesting an intrathecal synthesis of immunoglobulin G, and 26 patients (55%) presented identical oligoclonal bands in serum and CSF. Four patients (7%) had a positive CSF SARS-CoV-2 reverse-transcription polymerase chain reaction. Leptomeningeal enhancement was present on brain MR images in 20 patients (38%). CONCLUSIONS: Brain MR imaging abnormalities, especially leptomeningeal enhancement, and increased inflammatory markers in CSF are frequent in patients with neurological manifestations related to COVID-19, whereas SARS-CoV-2 detection in CSF remained scanty.

Bilateral symmetrical deep gray matter involvement and leptomeningeal enhancement in a child with MOG-IgG-associated encephalomyelitis.

BACKGROUND: Currently, myelin oligodendrocyte glycoprotein (MOG)-IgG-associated encephalomyelitis (MOG-EM) is regarded as an independent inflammatory demyelinating disease. Magnetic resonance imaging (MRI) abnormalities occur in 44.4% of patients with MOG-EM. However, symmetrical deep gray matter involvement with leptomeningeal enhancement is rarely described in the literature. CASE PRESENTATION: A 3-year-old boy was admitted to our hospital because of acute onset fever, headache, vomiting and disturbance of consciousness. Neurological examination showed somnolence, neck stiffness and positive Kernig's sign. Brain MRI demonstrated bilateral symmetrical lesions in the basal ganglia and thalamus as well as diffuse leptomeningeal enhancement along the sulci of bilateral hemisphere. Cerebrospinal fluid analysis demonstrated increased cell count (7 cells/mm3, mononuclear cells dominant) and protein (1.17 g/L) without glucose and chloride abnormality. Work-up for infectious and autoimmune causes, serum MOG IgG was positive by cell based assay. Therefore, a diagnosis of MOG-EM was established according to the international recommendatory criteria in 2018. He was administrated with intravenous methylprednisolone followed by oral corticosteroids and had recovered completely within 1 week. CONCLUSIONS: In the setting of meningoencephalitis-like clinical presentation with bilateral symmetrical deep gray matter involvement, MOG-EM should be distinguished from other infectious and autoimmune disorders, such as Epstein-Barr virus (EBV) encephalitis, Japanese encephalitis and Anti-NMDA receptor (NMDAR) encephalitis. Besides, aseptic meningitis associated with leptomeningeal enhancement may be an atypical phenotype of MOG-EM.

7T MRI cerebral leptomeningeal enhancement is common in relapsing-remitting multiple sclerosis and is associated with cortical and thalamic lesions.

BACKGROUND: Meningeal inflammation may contribute to gray matter (GM) involvement in multiple sclerosis (MS) and is proposed to manifest as magnetic resonance imaging (MRI) leptomeningeal enhancement (LME). OBJECTIVE: To investigate how LME relates to GM lesions in relapsing-remitting multiple sclerosis (RRMS) at 7T. METHODS: A total of 30 RRMS subjects (age (mean ± standard deviation (SD)): 44.0 ± 11.3 years, 93% on disease-modifying treatment) and 15 controls underwent gadolinium-enhanced three-dimensional (3D) MP2RAGE (magnetization-prepared 2 rapid gradient-echo) and fluid-attenuated inversion recovery (FLAIR) MRI. LME, cortical lesions (CLs), thalamic lesions (TLs), and white matter (WM) lesions were expert-quantified. Wilcoxon rank-sum, two-sample t-tests, Spearman correlations, and regression models were employed. RESULTS: Two-thirds (20/30) of MS subjects and 1/15 controls (6.7%) had LME. LME+ MS subjects had 2.7 ± 1.5 foci, longer disease duration (14.9 ± 10.4 vs. 8.1 ± 5.7 years, p = 0.028), increased CL number (21.5 ± 12.6 vs. 5.5 ± 5.0, p < 0.001) and volume (0.80 ± 1.13 vs. 0.13 ± 0.13 mL, p = 0.002), and increased TL number (3.95 ± 2.11 vs. 0.70 ± 1.34, p < 0.001) and volume (0.106 ± 0.09 vs. 0.007 ± 0.01 mL, p < 0.001) versus LME- subjects. LME focus number correlated more highly with CL (rs = 0.50, p = 0.01) and TL (rs = 0.81, p < 0.001) than WM lesion (rs = 0.34, p > 0.05) volume. Similar LME-CL number associations were observed in unadjusted and WM lesion-adjusted comparisons (both p < 0.001). CONCLUSION: Cerebral LME is common in RRMS at 7T and is independently associated with GM injury. We hypothesize that cerebrospinal fluid (CSF)-related inflammation links cortical and thalamic injury.

No association between cortical lesions and leptomeningeal enhancement on 7-Tesla MRI in multiple sclerosis.

BACKGROUND: Autopsy data suggest a causative link between meningeal inflammation and cortical lesions (CLs) in multiple sclerosis (MS). OBJECTIVE: To use leptomeningeal enhancement (LME) and CLs on 7-Tesla (7T) magnetic resonance imaging (MRI) to investigate associations between meningeal inflammation and cortical pathology. METHODS: Forty-one participants with MS underwent 7T MRI of the brain. CLs and foci of LME were quantified. RESULTS: All MS participants had CLs; 27 (65.8%) had >1 focus of LME. Except for hippocampal CL count (ρ = 0.32 with spread/fill-sulcal pattern LME, p = 0.042), no significant correlations were seen between LME and CLs. Mean cortical thickness correlated with the number of LME foci (ρ = -0.43, p = 0.005). Participants with relapsing-remitting multiple sclerosis (RRMS) showed no correlation with neocortical CLs, but significant correlations were seen between LME and hippocampal lesion count (ρ = 0.39, p = 0.030), normalized cortical gray matter (GM) volume (ρ = -0.49, p = 0.005), and mean cortical thickness (ρ = -0.59, p < 0.001). CONCLUSION: This study supports a relationship between LME and cortical GM atrophy but does not support an association of LME and neocortical CLs. This may indicate that meningeal inflammation is involved with neurodegenerative inflammatory processes, rather than focal lesion development.

The timelines of MRI findings related to outcomes in adult patients with new-onset refractory status epilepticus.

OBJECTIVE: To identify the timelines of magnetic resonance imaging (MRI) abnormalities and their relationships with the clinical outcomes of patients with new-onset refractory status epilepticus (NORSE). METHODS: This retrospective observational study enrolled patients with NORSE who were admitted from March 2008 to July 2018. MRI abnormalities were analyzed visually with the readers blinded to the clinical characteristics of the patients. Poor functional outcome was defined as a Glasgow Outcome Scale score ≤ 3 at discharge. Subsequent pharmacoresistant epilepsy was defined as seizures not controlled by two or more anti-seizure medications 6 months after discharge. RESULTS: Among 39 patients with NORSE, 32 (82.1%) exhibited an MRI abnormality. The most common abnormalities were persisting mesial temporal lobe signal abnormality (51.3%); initial diffuse leptomeningeal enhancement within 16 days from seizure onset (15/35, 42.9%); and hippocampal atrophy, which started to appear 26 days after seizure onset (15/26, 57.7%). Only three patients had claustrum abnormalities. Patients with insular involvement had longer treatment delay than those without (24.0 vs 5.5 hours, respectively, P = .02). Duration of status epilepticus (SE) tended to have a linear association with hippocampal atrophy (P = .055). Patients with diffuse leptomeningeal enhancement were more likely to have a poor functional outcome and to develop subsequent pharmacoresistant epilepsy than those without this finding (93.3% vs 15.0%, P < .001; 75.0% vs 22.2%, P = .004, respectively); the results were significant even after adjusting for age, sex, and duration of SE. Hippocampal atrophy and diffuse cortical atrophy were also significantly associated with poor functional outcomes (P = .001 and P = .002, respectively), and patients with these conditions were more likely to develop subsequent pharmacoresistant epilepsy than those without these conditions, after adjusting for age and sex (P = .035 and P = .048, respectively), but not after adjusting for duration of SE. SIGNIFICANCE: Initial diffuse leptomeningeal enhancement and later hippocampal atrophy were associated with a poor functional outcome and subsequent pharmacoresistant epilepsy.

Diffuse leptomeningeal glioneuronal tumour (DLGNT) with hydrocephalus as an initial symptom: a case-based update.

PURPOSE: Diffuse leptomeningeal glioneuronal tumour (DLGNT) is a rare disease classified in 2016. There are different views of the clinical, pathologic and neuroradiologic characteristics of DLGNT due to the minor studies on this disease. METHODS: We describe a case of a 12-year-old boy who initially presented intermittent headache, vomiting and communicating hydrocephalus. A literature review is also presented summarizing the clinical characteristics and treatments of DLGNT. RESULTS: In our case, a ventriculoperitoneal shunt was applied to reduce intracranial pressure caused by communicating hydrocephalus. T1-weighted contrast-enhanced magnetic resonance imaging (MRI) showed linear enhancement, and microscopy showed tumour-like spindle cells. The diagnosis of DLGNT was confirmed, and temozolomide was administered. The clinical characteristics were similar in the reported cases, while the treatments showed differences. CONCLUSION: Ventriculoperitoneal shunts are effective for patients with hydrocephalus-related intracranial hypertension. Chemotherapy including temozolomide has shown varying outcomes, and further studies are expected.

Vanishing diffuse leptomeningeal contrast enhancement in an infant with choroid plexus papilloma.

Choroid plexus tumors (CPT) can present in the baseline magnetic resonance imaging (MRI) with lesions compatible with leptomeningeal dissemination. Therapeutic strategy in this condition is controversial. We present a case of an infant with CPP and significant diffuse leptomeningeal contrast enhancement at diagnosis, which spontaneously resolved after removal of the primary tumor. In these challenging cases, several aspects, such as histopathological/molecular diagnosis and close radiological follow-up, should be taken into account to avoid unnecessary treatments.

Neurosarcoidosis Flare with Multifocal Restricted Diffusion: Stroke, Inflammation, or Both?

Sarcoidosis is a multisystem granulomatous disease that can cause a wide range of neurologic symptoms. Leptomeningeal enhancement is frequently described but reports of stroke-like symptoms or the appearance of ischemia on magnetic resonance imaging are rare. We present a case of a patient with both leptomeningeal enhancement and multifocal restricted diffusion in a patient with sarcoidosis.

Diffuse leptomeningeal glioneuronal tumor (DLGNT) mimicking Whipple's disease: a case report and literature review.

INTRODUCTION: Diffuse leptomeningeal glioneuronal tumor is a new entity under the neuronal and mixed neuronal-glial tumors in the WHO 2016 updated classification and commonly found in children and adolescents. The initial diagnosis is challenging because of its non-specific radiologic feature and negative CSF cytology analysis. A 17 years male was presented with intractable headache subsequently followed by back pain and joint pain. MRI showed enhancement of arachnoid membrane at basal cistern, bilateral sylvian fissure and cerebral cistern with slight enlargement of ventricles. There were no evidences of infection in CSF and blood samples. Based on the duodenal biopsy and prodromal symptom of joint pain, the patient was suspected of having Whipple's disease. Eleven months after the onset, a small mass lesion was observed at the anterior horn of right lateral ventricle. The histology was remarkable for anaplastic oligodendroglioma. Immunostainings revealed positivity for GFAP, Olig2, synaptophysin and negativity for IDH1 mutation, H3K27M. MIB1 labeling index was 40% and 1p19q FISH analysis showed only 1p deletion. Therefore, a final diagnosis of DLGNT was made. CONCLUSION: DLGNT should be included as a differential diagnosis of patients with leptomeningeal-enhanced and high CSF protein level with normal white blood cell count.

Leptomeningeal enhancement in Susac's syndrome and multiple sclerosis: Time to expect the unexpected?

Magnetic resonance imaging detection of leptomeningeal enhancement has long been considered a red flag for a diagnosis of multiple sclerosis. However, recent studies seem to suggest that leptomeningeal enhancement can be detected in up to 25% of patients with multiple sclerosis. The case reported here suggest a distinct set of features of leptomeningeal enhancement in a patient with Susac's syndrome which may still be helpful in the differential diagnosis between Susac's syndrome and multiple sclerosis.

An Atypical Presentation of a Patient With Neurosarcoidosis: A Case Report.

Neurosarcoidosis is a disease in which noncaseating granulomas, characteristic of sarcoidosis, are found within organs of the nervous system such as the brain and spinal cord. This case report highlights a 57-year-old male with worsening bilateral lower extremity weakness and numbness in addition to ptosis and oculomotor nerve palsy of the right eye. Computed tomography (CT) imaging showed mediastinal and hilar lymphadenopathy, which raised suspicion for neurosarcoidosis. Multiple biopsies were taken from lymph nodes in the mediastinal region, which resulted in non-necrotizing epithelioid cell granulomas, consistent with the suspected neurosarcoidosis. Medical providers must include neurosarcoidosis within a much broader differential diagnosis when encountering patients that present with a similar presentation shown in this case report so that treatment can be promptly initiated as soon as possible.

Candida dubliniensis meningitis in an immunocompetent patient: A case report and review of the literature.

Objective: We present the fifth case of candida dubliniensis meningitis in a young immunocompetent host and suggest extracorporeal membrane oxygenation (ECMO) as a potential risk factor for colonization. Methods: A 22-year-old immunocompetent female presented with a diagnosis of bacterial meningitis. Two years prior, she received ECMO for Covid-19 pneumonia complicated by viral myocarditis & Takutsobo cardiomyopathy. Following discharge, she reported headaches of increasing intensity, all refractory to treatments. Brain magnetic resonance imaging (MRI) was inconclusive. Two weeks prior to her presentation, she was admitted for worsening headaches with cranial nerve VI palsy. Lumbar puncture (LP) revealed white blood cell count (WBC) of 166 cells/µL with neutrophilic predominance and her symptoms progressed, despite 5 days of treatment with broad spectrum antibiotics. All cultures returned negative. Results: At her current presentation, repeat LP revealed 835 WBC/mm3, 225 mg/dL protein, and 4 mg/100 mL glucose. Brain MRI revealed nodular enhancement in the brainstem and communicating hydrocephalus. MRI of the lumbar spine revealed meningeal enhancement. Cerebrospinal fluid (CSF) cultures came back positive for C.dubliniensis. Treatment began with Amphotericin B and Flucytosine. Discussion: When clinical suspicion for fungal meningitis is high, repeate LP and CSF analysis is indicated to establish a definitive diagnosis and begin treatment. Additional studies are needed to confirm risk factors, like ECMO, for the colonization of C.dubliniensis, which likely predisposes individuals to invasive candidiasis.

A Rare Case of Diffuse Leptomeningeal and Cortical Enhancement Secondary to Stroke-Like Migraine Attacks After Radiation Therapy (SMART) Syndrome in a Patient With a History of Childhood Medulloblastoma.

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare complication of craniospinal irradiation (CSI). Patients commonly present with headaches, seizures, and paroxysmal focal neurological deficits. There is a dearth of studies reported in the literature with an estimated fewer than 100 cases described since it was initially defined in the mid-1990s. The authors present the case of a 23-year-old patient with a history of childhood medulloblastoma and prior ventriculoperitoneal shunt (VPS), chemotherapy, and CSI who presented with headaches and new-onset seizures. Magnetic resonance imaging (MRI) of the brain showed diffuse left temporoparietal and occipital leptomeningeal and cortical enhancement. However, cerebrospinal fluid (CSF) analysis was unremarkable for neoplastic, infectious, or inflammatory etiology. Initiation of systemic steroid therapy resulted in drastic improvement of the patient's symptoms and prompted antiepileptic drug (AED) wean and persistent resolution of leptomeningeal and cortical contrast enhancement on brain MRI. When evaluating MRI evidence of leptomeningeal enhancement, neurosurgeons should consider SMART syndrome in the differential diagnosis, especially when extensive workup rules out more common causes of this finding such as leptomeningeal disease (LMD). Proper identification of SMART syndrome can lead to timely treatment, avoidance of invasive procedures such as tissue biopsy, and improved clinical outcomes.

Cerebellar leptomeningeal enhancement: An imaging finding of rapidly progressive Purkinje cell cytoplasmic autoantibody type 1 paraneoplastic cerebellar syndrome.

Purkinje cell cytoplasmic autoantibody type 1 (PCA1), also known as anti-Yo, is a 'high-risk' paraneoplastic antibody, associated with rapidly progressive cerebellar syndrome. In patients with this syndrome, various MRI abnormalities have been documented, including atrophy in the cerebellum and brainstem, T2 hyperintensity in the brainstem and spinal cord, and cranial nerve enhancement. This report introduces an imaging finding, cerebellar leptomeningeal enhancement, which was observed in all three cases at early stages. Despite neurological deterioration, all patients underwent immunotherapy, and subsequent follow-up MRI revealed resolution of the leptomeningeal enhancement, suggesting that this feature is distinct from meningeal carcinomatosis.

Leptomeningeal enhancement in multiple sclerosis: a focus on patients treated with hematopoietic stem cell transplantation.

Background: Leptomeningeal enhancement (LME) is considered an MRI marker of leptomeningeal inflammation in inflammatory neurological disorders, including multiple sclerosis (MS). To our knowledge, no disease-modifying therapies (DMTs) have been demonstrated to affect LME number or morphology so far. Methods: Monocentric study investigating the frequency and number of LME in a cohort of people with (pw)MS who performed a 3 T brain MRI with a standardized protocol (including a post-contrast FLAIR sequence), and exploring the impact of autologous hematopoietic stem cell transplantation (AHSCT) on this marker. In a longitudinal pilot study, consecutive MRIs were also analyzed in a subgroup of pwMS, including patients evaluated both pre- and post-AHSCT. Results: Fifty-five pwMS were included: 24/55 (44%) had received AHSCT (AHSCT group) and 31 other treatments (CTRL group). At least one LME was identified in 19/55 (35%) cases (42 and 29% in the AHSCT and CTRL groups, respectively; p = 0.405). In the AHSCT group, LME number correlated with age at AHSCT (R = 0.50; p = 0.014), but not with age at post-treatment MRI. In the longitudinal pilot study (n = 8), one LME disappeared following AHSCT in 1/4 patients, whereas LME number was unchanged in the remaining four pwMS from the CTRL group. Discussion: These results suggest that AHSCT may affect development and persistence of LME, strengthening the indication for early use of effective therapies bioavailable within the central nervous system (CNS), and therefore potentially targeting compartmentalized inflammation.