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Various neurological complications can occur in multiple myeloma. We report a unique paraneoplastic neurological presentation that led to a multiple myeloma diagnosis. A man in his mid-40s experienced a 6-month progressive decline in vision and gait. Examination demonstrated an upper motor neuron pattern, while MRI showed bilateral corticospinal tractopathy and optic neuropathy. Workup led to a diagnosis of multiple myeloma, while other causes (eg, primary central nervous system demyelination, toxic-metabolic, degenerative) were ruled out. Paraneoplastic antibody panels were negative. There was no evidence of leptomeningeal meningitis or compressive lesions. He significantly improved after multiple myeloma treatment. We attribute his unique presentation to a probable paraneoplastic syndrome given the temporal relationships to multiple myeloma diagnosis and treatment. Paraneoplastic neurological syndromes in haematological cancers are often not well-defined, thus requiring both a broad evaluation and awareness of potential connections., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Paraneoplastic neurological syndromes (PNS) are mostly immune-mediated, tumor-associated disorders. Earlier the 2004 PNS criteria were used which are now partially outdated due to advances in PNS research and also identification of new phenotypes and antibodies that have transformed the diagnostic approach to PNS; hence, a new criterion was proposed in 2016. They can have multifarious presentations, ranging from behavioral abnormalities to altered sensorium and coma. They can precede, be synchronous with, or follow the diagnosis of malignancy. Treatment depends on the underlying antibody and malignancy. We hereby describe an unusual presentation with dual antibody positivity in a patient who was diagnosed with lung cancer in a hospital in the same presentation., (© Journal of The Association of Physicians of India 2024.)

Introduction: On the palliative care ward, we treated a man with a small cell lung cancer who was suffering from vertigo for six years, however the vertigo got stronger the last six months with pronounced coordination disorders. After several examinations, the cause was a paraneoplastic neurologic syndrome (PNS) with Hu-antibodies. PNS are various neurological malfunctions, which occur mostly in certain patterns. The pathogenesis is immune-mediated through a tumor. This is the reason why the treatment of the PNS is within the treatment of the tumor., Competing Interests: Die Autorin und der Autor haben keine Interessenkonflikte im Zusammenhang mit diesem Artikel deklariert., (© 2024 Aerzteverlag medinfo AG.)

Background and Objectives: To define the clinical and immunologic profile of patients with paraneoplastic neurologic syndromes (PNSs) associated with Merkel cell carcinoma (MCC)., Methods: Retrospective analysis was conducted on patients with suspected MCC-related PNS assessed at the French Reference Center, and cases were identified by a systematic review of the literature (MEDLINE, Embase) following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines., Results: A total of 17 patients were identified in our center and 30 in the systematic review, resulting in an overall cohort of 47 patients. The median age was 65 years (range 41-90), and 30 of 46 (65%) were men. Lambert-Eaton myasthenic syndrome (LEMS) (14/47, 29%), rapidly progressive cerebellar syndrome (11/47, 23%), and encephalomyelitis (EM) (8/47, 17%) were the most common associated clinical phenotypes. The most frequently associated neural antibodies (Abs) were voltage-gated calcium channel (VGCC)-Abs (14/45, 31%), followed by Hu-Abs (8/45, 17%) and neurofilament (NF)-Abs (8/45, 17%). Patients with NF-Abs only exhibited CNS disorders (8/8, 100%) and often had antibodies against >1 NF subunit (6/8, 75%). At onset, 26 of 43 patients (60%) had no identifiable primary skin tumor but had lymph node metastasis; these patients were more frequently men (21/26, 80%, vs 7/17, 41%; p = 0.007), had more frequently VGCC-Abs (12/26, 46%, vs 2/17, 11%, p = 0.02) predominantly among those with LEMS, and presented reduced mortality than patients with a known primary tumor (5/25, 20%, vs 8/15, 53%; p = 0.02)., Discussion: MCC-related PNSs present as a heterogeneous clinical spectrum including central and/or peripheral nervous system disorders such as LEMS, RCPS, and EM, mainly associated with VGCC-Abs, NF-Abs, and Hu-Abs. NF-Abs were only seen among patients with CNS disorders. At onset, the absence of a primary skin tumor but presence of lymph node metastasis is frequently observed, and this particular clinical presentation is linked to reduced mortality, highlighting distinctive clinical and immunologic features of MCC-related PNS.

Paraneoplastic neurological syndromes occur due to immune-mediated neuronal dysfunction secondary to systemic malignancy, and symptoms can usually be seen before malignancy. There are many subtypes that depend on the antibodies present or the proteins they target. Accurate epidemiological data are lacking as it is difficult to diagnose. We would like to present a case of anti-Yo antibody-associated encephalitis due to breast cancer in a 47-year-old male patient. When we searched the literature, we did not find a case of anti-Yo-associated autoimmune encephalitis due to breast adenocarcinoma in a male patient. For this reason, we find it worth presenting our case., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Neuromyelitis optica spectrum disorders (NMOSD) is one of autoimmune inflammatory diseases and is characterized by area postrema syndrome, brainstem syndrome, optic neuritis, and/or myelitis. Typical myelitis is longitudinally extended transverse myelitis (LETM) which extends over three vertebral bodies. Several previous case reports have suggested association between cancer and NMOSD. A 50-year-old woman had breast cancer and underwent mastectomy and, 10 months later, she had developed acutely progressive dysbasia. Spine MRI showed LETM in 13 vertebrae length and blood test revealed positive anti-aquaporin 4 (anti-AQP4) antibody based on enzyme-linked immunosorbent assay with index of over 40. She was treated by intravenous methylprednisolone, plasma exchange, and intravenous immunoglobulin, followed by oral prednisolone. The condition had mostly recovered after the treatment. A small population of NMOSD has the aspect of paraneoplastic neurological syndrome. The age of onset in patients with cancer-associated NMOSD tends to be higher than that in individuals with NMOSD due to any causes of NMOSD.

Introduction: Paraneoplastic encephalitis (PE) represents a rare but significant complication in patients with testicular cancer (TC). Given the paucity of comprehensive literature on this topic, our review seeks to consolidate current knowledge and provide evidence-based recommendations for the diagnosis, prognosis, and management of PE in the context of TC., Materials and Methods: In adherence to PRISMA guidelines, a systematic literature review was conducted from 1950 to April 2024 using PubMed. The search focused on articles where TC was identified as the primary etiology of PE. The Mixed Methods Appraisal Tool and the Oxford Centre for Evidence-Based Medicine's levels of evidence tool were employed for assessing study quality, and a thematic analysis was conducted to identify trends and patterns., Results: Out of 91 articles identified, 29 met the inclusion criteria, encompassing 5 retrospective chart reviews, 3 case series, and 22 case reports. Findings indicate that PE symptoms can manifest at any stage of TC-before tumor detection, during treatment, or even years posttreatment. A notable observation was the frequent oversight of microscopic testicular tumors in ultrasound imaging, leading to diagnostic delays. The outcomes of PE in the context of TC were diverse, reflecting the heterogeneity of the studies included., Conclusion: PE, although rare, is a critical consideration in patients with TC presenting with neuropsychiatric symptoms. Early recognition and appropriate diagnostic workup, including consideration for microscopic neoplasms, are essential for timely intervention and improved patient outcomes., Competing Interests: Disclosure The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Gastrointestinal pseudo-obstruction (GIPO) is a phenotype of the paraneoplastic neurological syndrome (PNS). We herein report a case of small-cell lung carcinoma (SCLC) with GIPO elicited by an immune checkpoint inhibitor (ICI). A 75-year-old man with SCLC developed intractable intestinal obstruction after receiving one course of anticancer drugs (durvalumab, etoposide, and carboplatin). The serum anti-Hu antibody (Hu-Ab) was positive, and the patient was diagnosed with GIPO. Corticosteroid treatment did not improve the GIPO, and the patient died. There are few reports of GIPO after ICI treatment in patients with lung cancer, so a further investigation will be required to elucidate the mechanism by which ICIs elicit PNS. Checking for neuronal antibodies may help identify patients with SCLC who are at risk of developing PNS due to ICI treatment.

Background and Objectives: Dysautonomia has been associated with paraneoplastic neurological syndrome (PNS)-related mortality in anti-Hu PNS, but its frequency and spectrum remain ill-defined. We describe anti-Hu patients with dysautonomia, estimate its frequency, and compare them to patients without dysautonomia., Methods: Patients with anti-Hu antibodies diagnosed in the study centre (1990-2022) were retrospectively reviewed; those with autonomic signs and symptoms were identified., Results: Among 477 anti-Hu patients, 126 (26%) had dysautonomia (the only PNS manifestation in 7/126, 6%); gastrointestinal (82/126, 65%), cardiovascular (64/126, 51%), urogenital (24/126, 19%), pupillomotor/secretomotor (each, 11/126, 9%), and central hypoventilation (10/126, 8%). Patients with isolated CNS involvement less frequently had gastrointestinal dysautonomia than those with peripheral (alone or combined with CNS) involvement (7/23, 30% vs. 31/44, 70% vs. 37/52, 71%; P = 0.002); while more frequently central hypoventilation (7/23, 30% vs. 1/44, 2.3% vs. 2/52, 4%; P < 0.001) and/or cardiovascular alterations (18/23, 78% vs. 20/44, 45% vs. 26/52, 50%; P = 0.055). Median [95% CI] overall survival was not significantly different between patients with (37 [17; 91] months) or without dysautonomia (28 [22; 39] months; P = 0.78). Cardiovascular dysautonomia (HR: 1.57, 95% CI [1.05; 2.36]; P = 0.030) and central hypoventilation (HR: 3.51, 95% CI [1.54; 8.01]; P = 0.003) were associated with a higher risk of death, and secretomotor dysautonomia a lower risk (HR: 0.28, 95% CI [0.09; 0.89]; P = 0.032). Patients with cardiovascular dysautonomia dying ≤ 1 year from clinical onset had severe CNS (21/27, 78%), frequently brainstem (13/27, 48%), involvement., Discussion: Anti-Hu PNS dysautonomia is rarely isolated, frequently gastrointestinal, cardiovascular and urogenital. CNS dysfunction, particularly brainstem, associates with lethal cardiovascular alterations and central hypoventilation, while peripheral involvement preferentially associates with gastrointestinal or secretomotor dysautonomia, being the latest more indolent., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

PNS are uncommon manifestations of cancer. The current literature about these syndromes in the setting of cHL is disintegrated. A systematic literature review of all published literature was conducted. One hundred twenty-eight patients from 115 publications met the inclusion/exclusion criteria. Eight-five patients were of the NS subtype (66.4%). The most frequent clinical presentation of the PNS was CNS manifestation (25.8%). The majority of patients were diagnosed with the cHL and PNS simultaneously (42.2%). In 33.6% of patients, the lymphoma diagnosis preceded the PNS diagnosis. In 16.4% of patients, the PNS diagnosis preceded the lymphoma diagnosis. The presence of PNS antibodies was reported in 35 patients (27.3%). Age older than 18 was associated with higher prevalence of PNS. The CR rate of the lymphoma was 77.3%. The complete resolution rate of the PNS was 54.7%. Relapse of lymphoma was reported in 13 patients, and recurrence of the PNS upon relapse was reported in 10/13 patients., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Paraneoplastic neurological syndromes (PNS) are rare neurological disorders arising from malignancy-triggered autoimmunity, yet their association with urothelial carcinoma remains unclear. This systematic review intends to explore any connection, alongside patient/clinical features and management. A literature search identified 25 cases of bladder and upper tract carcinoma linked to PNS. Overall, while infrequent, a meaningful association between PNS and urothelial carcinoma was found in that 84% of cases met a 'possible'-or-'higher-likelihood' PNS diagnosis. Most cases presented with high-risk PNS phenotypes, predominantly cerebellar syndromes and encephalomyelitis/sensory neuronopathy, ∼17 months within cancer diagnosis/recurrence. Review findings suggest a female preponderance in suspected PNS despite higher male incidence of urothelial cancer. Main treatments consisted of surgery alongside chemotherapy or immunotherapeutics (IVIG and/or corticosteroids), which improved symptoms for a slight majority (60%). Ultimately, while common PNS-associated neoplasms should always first be excluded in suspected PNS, in the absence of alternative causes, urothelial carcinomas do merit clinical consideration., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Paraneoplastic syndrome is a broad spectrum of signs and symptoms due to neoplasm, attributed to substances produced by tumor cells, or in response to it. Myasthenia gravis (MG) is a well-known paraneoplastic neurological syndrome (PNS), frequently associated with thymic abnormalities, but rarely reported in patients with lymphoplasmacytic lymphoma.This study presents the case of a 52-year-old Indonesian male patient who was diagnosed with Waldenstrom macroglobulinemia (WM), a rare B-cell neoplasm, after developing a new onset of MG with myasthenic crisis. the patient's MG features improved with Ibrutinib as a treatment targeted toward cancer. This is the first case report presenting the treatment response of Ibrutinib in WM with myasthenic crisis. The literature was reviewed to explain the possibility of MG as a paraneoplastic syndrome of WM and the treatment response of Ibrutinib for this patient, as well as summarizing previous case reports of concomitant MG and WM.MG should be considered a paraneoplastic malignancy syndrome, including WM, during diagnostic workup. Ibrutinib should also be considered when available to patients, due to its adequate response in both previously treated and treatment naïve patients.

Opinion Statement: Our understanding of paraneoplastic neurologic syndromes (PNS) has blossomed over the past few decades. Clinicians have access to more robust diagnostic criteria and have a heightened index of suspicion for these disorders. Nonetheless, treatment, which typically includes immunosuppression, and response to treatment, varies. Due to persistent difficulty in making a definitive diagnosis, we favor empiric treatment when a possible diagnosis of PNS is suspected, and other alternative causes have substantially been excluded (e.g., infections, toxic-metabolic derangements, metastasis, or leptomeningeal disease). Treatment of the underlying cancer, if identified, is the first therapeutic step and can prevent disease worsening and in rare cases, can reverse neurologic symptoms. In addition to anti-cancer treatment, first line immunotherapies, which include corticosteroids, intravenous immunoglobulins (IVIG), or plasma exchange (PLEX) are typically used. If partial or no benefit is seen, second line immunotherapeutic agents such as rituximab are considered. Additionally, the severity of the initial presentation and possible risk for relapse influences the use of the latter agents. Symptomatic management is also an important component in our practice and will depend on the syndrome being treated. One of the more novel entities we are facing currently is the management of immune checkpoint (ICI)-induced PNS. In those cases, current American Society of Clinical Oncology (ASCO) guidelines are followed., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors arising from the transformation of neuroendocrine cells in several organs, most notably the gastro-entero-pancreatic system and respiratory tract. The classification was recently revised in the 5th Edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. NENs can rarely spread to the central or peripheral nervous systems. Neurologic involvement is determined by the rare development of paraneoplastic syndromes, which are remote effects of cancer. Mechanisms depend on immunologic response to a tumor, leading to the immune attack on the nervous system or the production of biologically active ("functioning") substances, which can determine humoral (endocrine) effects with neurologic manifestations. Paraneoplastic neurologic syndromes (PNS) are immunologically mediated and frequently detected in small cell lung cancer but rarely seen in other forms of NEN. PNS and Merkel cell carcinoma is increasingly reported, especially with Lambert Eaton myasthenic syndrome. Endocrine manifestations are found in a wide spectrum of NENs. They can develop at any stage of the diseases and determine neurologic manifestations. Patient outcomes are influenced by tumor prognosis, neurologic complications, and the severity of endocrine effects., (Copyright © 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Paraneoplastic neurological syndromes are immune-mediated neurological attacks triggered by malignancies. They are commonly associated with lung, breast, thymus, gynaecological and haematological malignancies. We report a case of a male patient in his late 40s with paraneoplastic encephalomyelitis due to a colonic adenocarcinoma emphasising a low threshold for extensive cancer evaluation in all subacutely presenting neurological syndromes. We also emphasise that the absence of a positive onconeural antibody does not preclude the diagnosis of a paraneoplastic syndrome., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Paraneoplastic pemphigus (PNP), also called paraneoplastic autoimmune multiorgan syndrome (PAMS), is a rare autoimmune disease with mucocutaneous and multi-organ involvement. PNP/PAMS is typically associated with lymphoproliferative or haematological malignancies, and less frequently with solid malignancies. The mortality rate of PNP/PAMS is elevated owing to the increased risk of severe infections and disease-associated complications, such as bronchiolitis obliterans., Objectives: These guidelines summarize evidence-based and expert-based recommendations (S2k level) for the clinical characterization, diagnosis and management of PNP/PAMS. They have been initiated by the Task Force Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology with the contribution of physicians from all relevant disciplines. The degree of consent among all task force members was included., Results: Chronic severe mucositis and polymorphic skin lesions are clue clinical characteristics of PNP/PAMS. A complete assessment of the patient with suspected PNP/PAMS, requiring histopathological study and immunopathological investigations, including direct and indirect immunofluorescence, ELISA and, where available, immunoblotting/immunoprecipitation, is recommended to achieve a diagnosis of PNP/PAMS. Detection of anti-envoplakin antibodies and/or circulating antibodies binding to the rat bladder epithelium at indirect immunofluorescence is the most specific tool for the diagnosis of PNP/PAMS in a patient with compatible clinical and anamnestic features. Treatment of PNP/PAMS is highly challenging. Systemic steroids up to 1.5 mg/kg/day are recommended as first-line option. Rituximab is also recommended in patients with PNP/PAMS secondary to lymphoproliferative conditions but might also be considered in cases of PNP/PAMS associated with solid tumours. A multidisciplinary approach involving pneumologists, ophthalmologists and onco-haematologists is recommended for optimal management of the patients., Conclusions: These are the first European guidelines for the diagnosis and management of PNP/PAMS. Diagnostic criteria and therapeutic recommendations will require further validation by prospective studies., (© 2023 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.)

Introduction: The diagnosis of paraneoplastic neurologic syndromes is challenging when the primary tumor masquerades as scar tissue (i.e. "burned-out")., Methods: Case report., Results: A 45-year-old male patient presented with progressive cerebellar symptoms and hearing loss. Initial screening for malignancy and extensive testing of paraneoplastic and autoimmune neuronal antibodies gave negative results. Repeated whole-body FDG-PET CT revealed a single paraaortic lymphadenopathy, metastasis of a regressed testicular seminoma. Anti-Kelch-like protein-11 (KLHL11) encephalitis was finally diagnosed., Conclusion: Our case highlights the importance of continued efforts to find an often burned-out testicular cancer in patients with a highly unique clinical presentation of KLHL11 encephalitis., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Our case involved a 66-year-old woman who noticed progressive asymmetric involuntary movement, difficulty speaking, and difficulty swallowing. The patient fractured her femur due to a lower extremity involuntary movement while walking. During the course of her treatment for the fracture, her neurological symptoms worsened. Approximately 2 months after becoming aware of her symptoms, she visited our clinic for evaluation of difficulty with unassisted walking and weight loss due to dysphagia. To identify the cause of her neurological symptoms, hematological examination, brain magnetic resonance imaging, single-photon emission computed tomography for cerebral blood flow, electroencephalography, and a somatosensory evoked potential test were conducted. Although the cause of her neurological symptoms could not be determined, computed tomography revealed the presence of breast cancer, which led us to suspect paraneoplastic neurological syndrome (PNS). After breast cancer treatment, her neurological symptoms improved simultaneously. Therefore, the patient was retrospectively diagnosed with PNS. We report a case of PNS whose neurological symptoms followed a subacute course and were relieved after breast cancer treatment.

Objectives: Population-based epidemiologic data for paraneoplastic neurologic syndromes (PNSs) in the United States are lacking. Our objective was to evaluate the incidence, prevalence, and associated morbidity of PNS., Methods: We performed a population-based epidemiology study in Olmsted County, Minnesota, with patients identified between January 1, 1987, and December 31, 2018, using the medical records linkage system of the Rochester Epidemiology Project (REP) who met the definite/probable 2021 PNS criteria and 2004 PNS criteria. Patients with dermatomyositis and myasthenia gravis with underlying tumors were included. Age- and sex-specific population counts were obtained from REP resources for January 1, 2014 (prevalence denominator) and annually for 1987-2018 (incidence denominator). Morbidity was estimated using disability-adjusted life years (DALYs; years lived with disability [YLD] plus years of life lost [YLL])., Results: There were 28 patients with PNS identified (50% female) residing in Olmsted County, Minnesota, with median age at diagnosis of 54.5 (IQR 46.5-69.0) years. All patients had a cancer diagnosis, and 18 (64%) patients were neural autoantibody positive including antineuronal nuclear autoantibody type 1 (ANNA-1/anti-Hu; n = 1), ANNA-2/anti-Ri (n = 1), muscle-type acetylcholine receptor (AChR; n = 6), Purkinje cell cytoplasmic antibody type 1 (PCA-1/anti-Yo; n = 1), kelch-like protein 11 (KLH11; n = 3), collapsin response mediator protein 5 (CRMP-5/anti-CV2; n = 2), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (n = 1), neurofilament light chain (n = 1), leucine zipper 4 (LUZP4; n = 1), and unclassified neural antibodies (n = 1). PNS incidence was 0.6/100,000 person-years and increased over time from 0.4/100,000 person-years (1987-2002) to 0.8/100,000 person-years (2003-2018) ( p = 0.06). Prevalence was 5.4/100,000 people. The median follow-up period after PNS diagnosis was 3.1 years (IQR, 1.1-9.9 years). Total disability-adjusted life years (DALYs) for 28 patients with PNS were 472.7 years, based on total years of life lost (YLL) for patients dying between 1987 and 2018 (n = 15) of 445.3 years plus years lived with disability (YLD) 27.4 years., Discussion: PNSs are rare neurologic disorders but are associated with severe morbidity and mortality. The estimated number of prevalent PNS cases in the United States is 17,099, and predicted DALY for all US PNS cases is 292,393 years. Their apparent increasing rate of detection is attributable to increasing physician awareness and availability of serologic testing., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Background and Objectives: The two most common autoimmune encephalitides (AE), N -methyl-D-Aspartate receptor (NMDAR) and Leucine-rich Glioma-Inactivated 1 (LGI1) encephalitis, have been known for more than a decade. Nevertheless, no well-established biomarkers to guide treatment or estimate prognosis exist. Neurofilament light chain (NfL) has become an unspecific screening marker of axonal damage in CNS diseases, and has proven useful as a diagnostic and disease activity marker in neuroinflammatory diseases. Only limited reports on NfL in AE exist. We investigated NfL levels at diagnosis and follow-up in NMDAR and LGI1-AE patients, and evaluated the utility of CSF-NfL as a biomarker in AE., Methods: Patients were included from the National Danish AE cohort (2009-present) and diagnosed based upon autoantibody positivity and diagnostic consensus criteria. CSF-NfL was analyzed by single molecule array technology. Clinical and diagnostic information was retrospectively evaluated and related to NfL levels at baseline and follow-up. NMDAR-AE patients were subdivided into: idiopathic/teratoma associated or secondary NMDAR-AE (post-viral or concomitant with malignancies/demyelinating disease)., Results: A total of 74 CSF samples from 53 AE patients (37 NMDAR and 16 LGI1 positive) were included in the study. Longitudinal CSF-NfL levels was measured in 21 patients. Median follow-up time was 23.8 and 43.9 months for NMDAR and LGI1-AE respectively. Major findings of this study are: i) CSF-NfL levels were higher in LGI1-AE than in idiopathic/teratoma associated NMDAR-AE at diagnosis; ii) CSF-NfL levels in NMDAR-AE patients distinguished idiopathic/teratoma cases from cases with other underlying etiologies (post-viral or malignancies/demyelinating diseases) and iii) Elevated CSF-NfL at diagnosis seems to be associated with worse long-term disease outcomes in both NMDAR and LGI1-AE., Discussion: CSF-NfL measurement may be beneficial as a prognostic biomarker in NMDAR and LGI1-AE, and high CSF-NfL could foster search for underlying etiologies in NMDAR-AE. Further studies on larger cohorts, using standardized methods, are warranted., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Nissen, Ryding, Nilsson, Madsen, Olsen, Halekoh, Lydolph, Illes and Blaabjerg.)

Autoimmune encephalitis with antibodies against the gamma-aminobutyric acid-B receptor is a relatively rare disease. We report a case with characteristic symptoms of limbic encephalitis associated with combined small cell lung carcinoma. The brain magnetic resonance imaging showed bilateral temporal lesions and the photoemission tomography revealed regional heterogenous metabolism across the brain. The double labeling of anti-gamma-aminobutyric acid-B receptor autoantibodies both in the tissues of neuroendocrine and small cell neoplasia was a unique feature of this patient., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Paraneoplastic syndrome is a distant effect caused by malignant tumors, which is related to the production of cellular immune response. The nervous system is the most common involved system of paraneoplastic syndrome. It is easy to be misdiagnosed. Lung cancer is the most common cancer relating to paraneoplastic neurological syndrome (PNS)., Method: This study retrospectively analyzed clinical data of patients with the combination of PNS and lung cancer between January 2005 and March 2021 at Qilu Hospital of Shandong University, China., Results: A total of 111 patients were diagnosed with lung cancer complicated with PNS. A total of 95 (85.6%) cases had neurological symptoms as the first symptom. Sixty-three cases had the pathological results. A total of 43 (68.3%) of small cell lung cancer (SCLC) were diagnosed. PNS patients diagnosed with SCLC included peripheral neuropathy (15 cases, 34.9%). PNS patients diagnosed with non-small cell lung cancer (NSCLC) included peripheral neuropathy (6 cases, 30%) and limbic encephalitis (6 cases, 30%). Anti-Hu is popular in patients with SCLC (12 cases, 42.9%) and NSCLC (6 cases, 40%)., Conclusions: Most patients with PNS had neurological symptoms as the first symptom. It was more common in males. It had a higher incidence in SCLC. Peripheral neuropathy was the most common PNS associated with SCLC, followed by Lambert-Eaton syndrome. Peripheral neuropathy and limbic encephalitis were the most common PNS associated with NSCLC. Anti-Hu is the most common antibodies both in SCLC and NSCLC. Tumor markers do not have significant difference between different pathological types., (© 2021 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.)

Background and Objectives: Despite immense progress of imaging and updates in the MacDonald criteria, the diagnosis of multiple sclerosis remains difficult as it must integrate history, clinical presentation, biological markers, and imaging. There is a multitude of syndromes resembling multiple sclerosis both clinically or on imaging. The goal of this review is to help clinicians orient themselves in these various diagnoses. We organized our review in two categories: inflammatory and autoimmune diseases that are close or can be confused with multiple sclerosis, and non-inflammatory syndromes that can present with symptoms or imaging mimicking those of multiple sclerosis., Method: Review of literature CONCLUSION: Progress of imaging and biological sciences have drastically changed the approach and management of multiple sclerosis. But these developments have also shined a light on a variety of diseases previously unknown or poorly known, therefore greatly expanding the differential diagnosis of multiple sclerosis. While autoimmune, many of these diseases have underlying biological mechanisms that are very different from those of multiple sclerosis, rendering MS therapies usually inefficient. It is crucial to approach these diseases with utmost thoroughness, integrating history, clinical exam, and evolving ancillary tests., (Copyright © 2021. Published by Elsevier Masson SAS.)

Paraneoplastic autoimmune encephalitis (PAE) represents a group of rare neurological syndromes associated with neoplastic diseases. Here, we report a case that multiple anti-neuronal antibodies were present in a patient with PAE who developed both small cell lung cancer and colorectal adenocarcinoma. Furthermore, the immunopathological investigation of the colorectal adenocarcinoma revealed the formation of abnormal neuronal antigens and a massive infiltration of plasma cells in the tumor tissue. These findings support the hypothesis that expression of neuronal antigens in neoplasm initiates autoimmune responses in PAE., (© 2021 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

A 75-year-old man was hospitalised for bronchoscopy with biopsy due to a suspicious pulmonary mass at chest tomography. He had significant dyspnoea, constipation, nausea, vomiting, anorexia and a 33% loss of weight in the past 3 months. Biopsy revealed a pulmonary squamous cell carcinoma, which was inoperable. Tramadol used at home for 3 months was replaced by morphine on admission. The patient remained constipated despite prokinetics and laxatives, leading to the diagnostic hypothesis of paraneoplastic motility disorder and opioid-induced constipation. Abdominal tomography ruled out the possibility of mechanical obstruction. As complications, the patient presented superior vena cava syndrome and opioid (morphine) intoxication. The patient died a few days later. The management of this case highlights the importance of multidisciplinary care and the challenges of palliative oncology care. Paraneoplastic motility disorder must always be considered among the mechanisms of intestinal dysfunction in patients with advanced oncological disease., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

A 66-year-old woman with small-cell lung cancer and cancer-associated retinopathy with anti-recoverin antibodies presented with subacute paraplegia associated with recurrence of lung cancer. Although a spinal cord MRI did not show any visible lesion, the neurological symptoms and cerebrospinal fluid findings indicated myelitis. Anti-CV2/CRMP5 antibodies were also positive and the patient was diagnosed with paraneoplastic myelopathy. After medication with prednisolone, her neurological symptoms improved and she survived over three years without recurrence of neurological symptoms. In general, paraneoplastic myelopathy is refractory against immunotherapy but in this case, immunotherapy was successful and resulted in long-term survival. We recommend examining anti-neuronal antibodies and choose and continue the appropriate immunotherapy.

Purpose: Merkel cell carcinoma is highly sensitive to both radiation and immunotherapy. Moreover, concurrent radioimmunotherapy may capitalize on anti-tumor immune activity and improve Merkel cell treatment response, although an enhanced immune system may cross-react with native tissues and lead to significant sequelae., Methods: Here we present a case study of a patient with metastatic Merkel cell carcinoma treated with radiotherapy concurrent with pembrolizumab., Results: After radioimmunotherapy, the patient developed sensory neuropathy, visual hallucinations, and mixed motor neuron findings. Neurologic dysfunction progressed to profound gastrointestinal dysmotility necessitating parenteral nutrition and intubation with eventual expiration., Conclusion: This case represents a unique autoimmune paraneoplastic neurologic syndrome, likely specific to neuroendocrine tumors and motivated by concurrent radioimmunotherapy. Recognition of the potential role of radioimmunotherapy may provide an advantage in anticipating these severe sequelae.

Patients with craniopharyngioma are susceptible to autonomic dysfunction as a result of hypothalamic damage. We evaluated indices of heart rate variability (HRV) in patients with childhood-onset craniopharyngioma to investigate autonomic function and its relationship with components of the metabolic syndrome (MetS). This cross-sectional, case-only study included 53 patients (10-30 years of age). We measured the standard deviation of all normal R-R intervals (SDNN) and total power indicating overall HRV, the root-mean square of the difference of successive R-R intervals (RMSSD) and high frequency indicating parasympathetic modulation, and low frequency. These indices were compared according to the presence of the MetS. During the mean 10.8 years of follow-up, 25% of patients were diagnosed with the MetS. Patients with the MetS showed significantly lower levels of SDNN (29.0 vs. 40.6 ms), total power (416.1 vs. 1129.6 ms 2 ), RMSSD (20.1 vs. 34.5 ms), high frequency (94.7 vs. 338.5 ms 2 ), and low frequency (94.5 vs. 289.4 ms 2 ) than those without (p <0.05, for all). Individual components of the MetS including insulin resistance, serum triglycerides levels, and systolic blood pressure were inversely associated with SDNN, total power, RMSSD and high frequency. Higher overall variability and parasympathetic modulation were related to decreased odds ratios for having the MetS (OR 0.91, p=0.029 for SDNN; OR 0.91, p=0.032 for total power). In conclusion, autonomic dysfunction, as evidenced by reduced HRV indices, is associated with increased cardiometabolic risk in patients with childhood-onset craniopharyngioma., Competing Interests: The authors declare that they have no conflict of interest., (© Georg Thieme Verlag KG Stuttgart · New York.)

Introduction: Encephalitis with gamma-aminobutyric acid (GABA)-B receptor antibodies (GABA-B receptor encephalitis) is known to have underlying neoplastic condition in half of the cases; however, there could be an additional event that could work as a trigger factor. Here, we report a patient with GABA-B receptor encephalitis associated with small cell lung cancer, which was probably triggered by enterovirus encephalitis., Case Report: A 53-year-old man was admitted for a seizure, following fever and headache for 3 days. Status epilepticus developed on the following day. Brain magnetic resonance imaging (MRI) was normal. Cerebrospinal fluid (CSF) study revealed lymphocyte-dominant pleocytosis, and enterovirus was detected by polymerase chain reaction test in CSF later. The patient recovered after 2 weeks of treatment. Another 2 weeks later, he showed confusion and seizure without fever. Follow-up CSF study revealed no abnormalities; however, MRI showed a lesion with vasogenic edema on the right posterior hippocampus. GABA-B receptor antibodies were found in the serum and CSF. The chest computed tomography revealed a mass on his right upper lung, which was confirmed as a small cell lung cancer. GABA-B receptor encephalitis associated with small cell lung cancer was diagnosed, and intravenous immunoglobulin and methylprednisolone were infused. Following treatment, seizures and delirium stopped, and the patient recovered to a near normal state. Follow-up MRI performed 2 months later showed that the hippocampal lesion had disappeared., Conclusion: In cases of infectious encephalitis with an atypical recurrent course, the possibility of newly onset autoimmune encephalitis should be considered.

This case series discusses 3 male patients in their 60s who presented with a chief complaint of sensory disorder in the upper or lower limbs. The patients were diagnosed with small-cell lung cancer(SCLC)with anti-Hu antibody-positive paraneoplastic neurological syndrome(PNS). Chest radiography at the initial visit revealed abnormalities in only one of the 3 cases. To confirm the diagnosis, a bronchoscopy was performed. However, the diagnosis could be confirmed in only 1 patient. In the other 2 patients, a diagnosis could not be made due to the small size of the primary lung tumor. The diagnosis was confirmed in the other 2 cases using endobronchial ultrasound-guided transbronchial needle aspiration at another hospital. Chemoradiotherapy led to tumor reduction in 2 patients. However, in all patients, the neurological symptoms could not be resolved with steroids, immunoglobulin, or anti-tumor treatment. For neurological disorders due to possible PNS, the anti-Hu antibody test, chest computed tomography, and ultrasonic bronchoscopy should be performed to ensure early diagnosis and treatment of SCLC.

Paraneoplastic neurological syndromes (PNSs) are uncommon complications of immune-checkpoint inhibitor (ICI) therapy. This article reports a case of paraneoplastic encephalitis and enteric neuropathy associated with anti-Hu antibody in a patient with advanced small cell lung cancer. Symptoms presented in the third week after the second dose of sintilimab therapy and manifested as focal seizures and intestinal pseudo-obstruction. The patient's neurological symptoms improved significantly after treatment with intravenous infusion of methylprednisolone and sequential oral prednisone. This is the first report of sintilimab-related neurological adverse events. On the basis of this case, we speculate that ICIs may induce PNSs. Identifying relevant biomarkers may be instructive for the diagnosis and treatment of small cell lung cancer patients, and discontinuing ICIs and treatment with immunosuppressive in the early stages of PNSs may contribute to a better prognosis.

We present an illustrative case of a 62-year-old woman with small cell lung cancer who developed progressive worsening of pre-existing anti-Hu antibody associated sensory neuronopathy after treatment with programmed cell death-1 (PD-1) inhibitor, nivolumab. We review the literature and identify 6 reported cases to understand the clinical outcomes of patients with anti-Hu paraneoplastic neurologic syndrome (PNS) treated with anti-PD-1 treatment. The PNS clinical spectrum comprised of encephalitis, a combination of sensory neuronopathy and anti-NMDAR encephalitis, isolated sensory neuronopathy, and encephalomyelitis. Immune checkpoint inhibitor have the potential to worsen pre-existing anti-Hu PNS and may promote the development of anti-Hu PNS., Competing Interests: Declaration of Competing interest PR- The author declares that she has no competing interests. DH- The author declares that she has no competing interests. KG- The author serves on advisory boards for Sanofi Genzyme and Eli Lilly. JS- The author declares that she has no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Paraneoplastic encephalitis encompasses a diverse spectrum of neurological disorders associated with a variety of pediatric tumor types., Methods: We describe a seven-year-old boy with paraneoplastic necrotizing encephalitis associated with precursor B-cell acute lymphoblastic leukemia., Results: The initial presentation involved acute-onset upper extremity weakness, seizure-like activity, and agitation. Extensive evaluation revealed pancytopenia, elevated protein in the cerebrospinal fluid, and normal magnetic resonance imaging (MRI) consistent with a clinical diagnosis of encephalitis of presumed viral etiology. He was treated with antimicrobials and intravenous immunoglobulin and returned to his neurological baseline before discharge. One month later, he was diagnosed with precursor B-cell acute lymphoblastic leukemia. Before chemotherapy initiation, he again became encephalopathic. Repeat cerebrospinal fluid evaluation showed elevated protein, and MRI revealed findings consistent with diffuse necrotizing encephalitis. He received standard chemotherapy as well as immunotherapy with intravenous immunoglobulin and plasmapheresis, with resolution of MRI abnormalities and improvement in neurological status. At six years postpresentation, he is in remission for acute lymphoblastic leukemia, without significant neurocognitive deficits and mild right spastic hemiparesis., Conclusion: This is the first report of paraneoplastic encephalitis associated with pediatric leukemia. A hematologic malignancy should be considered in the differential diagnosis of paraneoplastic encephalitis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Both the onset of various malignancies as well as the treatment of cancer can lead to neurologic symptoms which can be difficult to diagnose. In this review, we highlight the varied ways in which neurologic sequelae of cancer and its treatment manifest in children. Initial neurologic presentation may be secondary to mass effect or to immune-mediated paraneoplastic syndromes. Treatment effects on the nervous system may arise from surgery, chemotherapy, radiation, or bone marrow transplantation. In addition, the rapidly expanding field of immunotherapies for cancer has generated numerous new approaches to eradicating cancer including monoclonal antibodies, checkpoint inhibitors, and chimeric antigen receptor T cells (CAR-T cells), which have neurologic side effects mediated by immune responses that are also being recognized. Here we review common consult questions to the neurologist and our general approach to these scenarios including altered mental status, headaches, seizures, and sensorimotor complaints, considering the multifactorial nature of each.

Objective: To report the presence of a new neuronal surface antibody against the metabotropic glutamate receptor 2 antibody (mGluR2-Ab) in 2 patients with paraneoplastic cerebellar ataxia., Methods: mGluR2-Abs were initially characterized by immunohistochemistry on the rat brain and confirmed by immunofluorescence on HEK293 cells transfected with mGluR2. Additional studies included analysis of potential cross-reactivity with other mGluRs, expression of mGluR2 in patients' tumors, and the effects of mGluR2-Abs on cultures of rat hippocampal neurons., Results: Patient 1 was a 78-year-old woman with progressive cerebellar ataxia with an initial relapsing-remitting course who developed a small-cell tumor of unknown origin. Patient 2 was a 3-year-old girl who presented a steroid-responsive acute cerebellitis preceding the diagnosis of an alveolar rhabdomyosarcoma. Patients' serum and CSF showed a characteristic immunostaining of the hippocampus and cerebellum in rat brain sections and immunolabeled the cell surface of live rat hippocampal neurons. HEK293 cells transfected with mGluR1, 2, 3, and 5 confirmed that patients' antibodies only recognized mGluR2. mGluR2-Abs were not detected in 160 controls, 120 with paraneoplastic, autoimmune, or degenerative ataxias, and 40 with autoimmune encephalitis and antibodies against mGluR5 or unknown antigens. Expression of mGluR2 in tumors was confirmed by immunohistochemistry using a commercial mGluR2-Ab. Incubation of live rat hippocampal neurons with CSF of patient 2 did not modify the density of surface mGluR2 clusters., Conclusions: mGluR2-Abs are a novel biomarker of paraneoplastic cerebellar ataxia. The potential pathogenic effect of the antibodies is not mediated by downregulation or internalization of neuronal surface mGluR2., (Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Acquired polyneuropathies (PN) are rare in childhood and adolescent. We report on a 15-year-old male patient who presented with progressive gait instability, ataxia, neuropathic pain, distal muscle weakness and progressive loss of ambulation. Nerve conduction studies (NCS) revealed a progressive demyelinating sensorimotor polyneuropathy predominantly of the lower limbs. Cerebrospinal fluid (CSF) analyses revealed a cytoalbuminologic dissociation. Extensive diagnostic workup for autoantibodies and inflammatory markers was inconclusive. Corticosteroids and intravenous immunoglobulins did not affect. Cranial MRI revealed leptomeningeal enhancement of the cerebellum and the brainstem. Brain biopsy of the cerebellar lesions revealed an unclassifiable sarcoma. The patient was treated according to the CWS guidance study resulting in a decrease in enhanced lesion size. After two years NCS still revealed a demyelinating sensorimotor PN. This case report describes for the first time the clinical course of a chronic PN, putative paraneoplastic, associated with isolated unclassifiable CNS-sarcoma in an adolescent patient. Paraneoplastic pathogenesis should be considered in an unusual sequence of subacute progressive neurological symptoms even in children and adolescents., (Copyright © 2019 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Paraneoplastic neurological syndromes (PNS) constitute a heterogeneous group of cancer-related disorders that can affect any level of the central and peripheral nervous system. There is compelling evidence that PNS are caused by an immune response directed against neural antigens that are abnormally expressed by the tumour. PNS are frequently associated with neural-specific autoantibodies whose characterization has direct implications for diagnostic workup, treatment and outcome. The last decade has seen a dramatic rise in the discovery of novel autoantibodies associated with PNS, which has led to more accurate diagnoses and earlier treatments, potentially resulting in better outcomes. The latest advancements in the field of autoimmune neurology have paved the way to a more comprehensive understanding of PNS; yet, many aspects of their immunopathogenesis remain to be elucidated and patient-tailored treatment strategies still need to be optimized., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Paraneoplastic syndromes are signs or symptoms that result from tissue damage at locations remote from tumour sites. Paraneoplastic syndromes associated with cancer of unknown primary (CUP) are not well recognized as they are rarely reported. These syndromes can impair various organ functions and include endocrine, neurologic, dermatologic, rheumatologic, hematologic and several other system alterations. To our knowledge, the association between the histological CUP type and the paraneoplastic syndrome has never been assessed. In some instances, paraneoplastic syndromes can become the major clinical problems determining survival. However, they can also herald earlier the occurrence of CUP in patients with asymptomatic tumors. In this article, we review the available literature of CUP patients presenting paraneoplastic syndromes by trying to collect all available published cases during the last three decades. One additional goal of this article is to make practicing oncologists aware of the coexistence of paraneoplastic syndromes in patients with CUP., (Copyright © 2019 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)