Peripheral nervous system involvement in lymphomas

Neuropathy with anti-myelin-associated glycoprotein antibodies: update on diagnosis, pathophysiology and management

Antimyelin-associated glycoprotein (MAG) neuropathy is a rare autoimmune demyelinating peripheral neuropathy caused by IgM autoantibodies targeting MAG. The typical presentation is that of a slowly progressive, distal, length-dependent, predominantly sensory, sometimes ataxic neuropathy, frequently accompanied by upper limb tremor. Distal motor weakness may subsequently occur. The clinical presentation may vary and rarely be consistent with that of typical chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), as well as have an aggressive and rapidly disabling course. The diagnosis of anti-MAG neuropathy is based on the detection of anti-MAG antibodies through ELISA or western blot analysis, primarily in presence of an IgM monoclonal gammopathy. Anti-MAG neuropathy may occur without or with haematological malignancy. Electrophysiology is characteristic of a predominantly distal demyelinating neuropathy. Intravenous immunoglobulins and plasma exchange have unproven benefits, but may provide short-term effects. Cytotoxic therapies are commonly used, although without an evidence base. Rituximab, an anti-B-cell monoclonal antibody was studied in two randomised controlled trials, neither of which achieved their primary outcome. However, a meta-analysis of these two studies demonstrated improvement of disability at 8-12 months. A recent trial with lenalidomide was interrupted prematurely due to a high rate of venous thromboembolism. There are currently two ongoing trials with Bruton's tyrosine kinase inhibitors. Symptom control is otherwise frequently needed. Outcome measures used for other inflammatory neuropathies present limitations in anti-MAG neuropathy. International registries such as the planned IMAGiNe study may, in future, provide answers to the many remaining questions.

Top 10 Clinical Pearls in Paraproteinemic Neuropathies

Paraproteinemic neuropathies represent an important subset of peripheral neuropathies. Once identified, further evaluation into the paraproteinemic subtype, clinical exam pattern, and electrodiagnostic phenotype helps clarify if the paraproteinemia is coincidental or causal of the neuropathy, as not all paraproteinemias cause neuropathy. Of all paraproteinemias, immunoglobulin M (IgM)-associated peripheral neuropathy, or IgM neuropathy, is of particular importance as half of IgM neuropathies also harbor anti-myelin-associated glycoprotein antibodies, which produce a characteristic demyelinating pattern on nerve conduction testing. Immunoglobulin G and immunoglobulin A paraproteinemias are less strongly associated with peripheral neuropathy, except in the setting of multiple myeloma or osteosclerotic myeloma (POEMS syndrome), which have characteristic systemic features. In multiple myeloma, chemotherapy is more likely to result in neuropathy than the myeloma itself. Finally, the presence of systemic features (e.g., cardiomyopathy, nephropathy, recurrent carpal tunnel syndrome, and autonomic insufficiency) should raise concern for hereditary or acquired light (AL) chain amyloidosis. AL amyloidosis can occur in the setting of any light or heavy chain paraproteinemia. Central to the proper evaluation of paraproteinemic neuropathy is electrodiagnostic testing, which helps delineate axonal versus demyelinating paraproteinemic neuropathy, the latter often misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy.

High-grade B-cell lymphoma manifested as peripheral nerve injury: A case report

RATIONALE

High-grade B-cell lymphoma is highly malignant and progresses rapidly, often being at the intermediate or advanced stage with poor prognosis when detected. This disease involves the central nervous system in 9% to 45% of cases, while peripheral nerve injury is relatively rare.

PATIENT CONCERNS

A 42-year-old male was admitted to the hospital due to recurrent peripheral facial paralysis lasting for 8 months and weakness in both lower extremities lasting for 1 month. No other symptoms and signs were apparent.

DIAGNOSES

Fluorescence in situ hybridization showed the following results: IgH/Bcl2 t(14:18)(q32;q21) chromosomal translocation: negative; Bc16 gene translocation: positive; and Myc(8;q24) chromosomal translocation: positive. The clonal gene rearrangement test for B-cell lymphoma was positive, and the clonal gene rearrangement test for T-cell lymphoma was negative.The patient was diagnosed with high-grade B-cell lymphoma.

INTERVENTIONS

The treatment plan included chemotherapy, targeted drug therapy, biological therapy, immunotherapy, etc.

OUTCOMES

The patient who was followed up for 1 and 3 years had stable conditions and was able to take care of himself, with an mRS score of 1. Five years after the initial diagnosis, the patient experienced recurrence and systemic metastasis of high-grade B-cell lymphoma, ultimately dying from multiple organ failure.

LESSONS

Lymphoma manifests mainly as progressive impairment of multiple cranial nerves or recurrent alternating peripheral nerve injury complicated with elevated protein concentrations in cerebrospinal fluid; it can be easily misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy. Performing lymph node biopsy for high-grade B-cell lymphoma as early as possible helps detect lymphoma in the early stage.

Clinical Reasoning: Progressive Peripheral Neuropathy in a 66-Year-Old Woman With Sezary Syndrome

Evaluating patients with neuropathy is common, especially in elderly patients with comorbidities. Neuropathy can often be a manifestation of systemic diseases, cancer, or drug-induced toxicity; thus, the differential diagnosis is challenging. The mechanism of nerve damage can vary significantly, affecting the patient's therapeutic management. We describe a 66-year-old woman who presented with subacute and progressively worsening motor weakness of the lower extremities with bilateral numbness and tingling after a recent respiratory tract infection. Her medical history included diabetes mellitus and Sezary syndrome in the context of cutaneous T-cell lymphoma. This case emphasizes the significance of a detailed evaluation and considering clinical signs and electrophysiologic findings in patients with neuropathy and a history of hematologic malignancy. Early recognition and management can be crucial in shaping the clinical course of the disease.

Primary neurolymphomatosis presenting as foot drop: A rare case report

ABSTRACT

Neurolymphomatosis (NL) is the direct infiltration of the peripheral nervous system (PNS) by lymphoma cells and represents the least common form of PNS involvement by lymphoma. Clinical presentation is varied, and early diagnosis remains challenging. Nerve biopsy remains the diagnostic gold standard, use of magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) may help in diagnosis and selecting targets for biopsy. We report an account of an older male patient who presented with subacute onset multifocal neuropathy involving bilateral lower limbs and left foot drop. The patient was initially misdiagnosed as chronic inflammatory demyelinating polyneuropathy; however radiological assessment revealed fusiform thickening of the L5 nerve root and biopsy from the site revealed extensive infiltration by diffuse large B cell type non-Hodgkin lymphoma (NHL). High index of suspicion is vital to ensure correct diagnosis, timely treatment, and to improve patient survival.

Recent insights into haematology and peripheral nerve disease

PURPOSE OF REVIEW

The association between clonal haematological disorders and peripheral nerve disease is recognized. Paraproteinaemic phenomena are the most common mechanism, but direct neural lymphomatous infiltration is seen and can be challenging to diagnose. Traditional and novel anticancer therapies have neuropathic side effects.

RECENT FINDINGS

Novel studies using sensitive techniques are refining the incidence of peripheral neuropathy in patients with a monoclonal gammopathy, and the pathogenesis of IgM Peripheral neuropathy (PN) and POEMS syndrome. Recent series give insight into the characteristics and diagnostic challenges of patients with neurolymphomatosis and amyloid light chain amyloidosis. There is an increasing repertoire of effective anticancer drugs in haematological oncology, but chemotherapy-related neuropathy remains a common side effect.

SUMMARY

This review of the current literature focuses on recent updates and developments for the paraproteinaemic neuropathies, and the evaluation, diagnosis and treatment of peripheral nerve disease due to high-grade and low-grade lymphomas and lymphoproliferative disorders.

Anaplastic Large Cell Lymphoma of the Spine: Report of a Rare Case

This abstract discusses a rare case of anaplastic large cell lymphoma (ALCL) involving the cervical and dorsal spine in a 17-year-old female. ALCL is a distinct subtype of lymphoma characterized by abnormal proliferation of lymphocytes and is divided into ALK-positive and ALK-negative subtypes. Spinal involvement in ALCL is uncommon, particularly in the cervical and dorsal regions. The patient presented with persistent fever, weakness, and delayed onset of severe neck pain. Diagnosis involved imaging, bone marrow biopsy, and lymph node biopsy. Treatment strategies for ALCL typically involve a multimodal approach, including chemotherapy, radiotherapy, and targeted therapy. However, due to the rarity of spinal involvement, treatment decisions are based on extrapolation from other ALCL cases. Prognosis is influenced by disease stage and ALK status, but specific outcomes for spinal involvement remain poorly established. This case emphasizes the need for considering lymphoma in patients with unexplained symptoms and abnormal imaging findings. It highlights the importance of further research to improve the understanding and management of ALCL with spinal involvement.

Sciatic diffuse large B-cell lymphoma with treatment response to CHOP and radiotherapy

Neurolymphomatosis is an uncommon presentation of lymphoma caused by the infiltration of the peripheral nervous system by lymphoid cells. Here, we describe a case of neurolymphomatosis of the sciatic nerve in 41-year-old woman, which presented by acute onset pain and progress to paresthesia and weakness. Magnetic resonance imaging (MRI) revealed lobulated mass involving the right sciatic nerve with central necrosis and mild surrounding edema, which was isointense on T1-weighted images, hyperintense on short tau inversion recovery (STIR). Positron emission tomography and computed tomography (PET-CT) showed centrally necrotic mass with avid fluorodeoxyglucose (FDG) uptake in the right sciatic nerve. Partial resection of the tumor was done, and the diagnosis of the diffuse large B-cell lymphoma was made and confirmed by bone marrow biopsy. Patient was treated with R-CHOP chemotherapy (regimen consisting of cyclophosphamide, doxorubicin, prednisone, rituximab, and vincristine) and radiotherapy.

Hematologic malignancies and hematopoietic stem cell transplantation

Paraneoplastic neurologic syndromes are rarely associated with hematologic malignancies. In their rarity, lymphomas are the diseases with more frequent paraneoplastic neurologic syndrome. High-risk antibodies are absent in most lymphoma-associated paraneoplastic neurologic syndromes, with the exception of antibodies to Tr/DNER in paraneoplastic cerebellar degeneration, mGluR5 in limbic encephalitis, and mGluR1 in some cerebellar ataxias. Peripheral nervous system paraneoplastic neurologic syndromes are rare and heterogeneous, with a prevalence of demyelinating polyradiculoneuropathy in non-Hodgkin lymphoma. Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) is a rare, paraneoplastic syndrome due to an underlying plasma cell disorder. The diagnosis is based on defined criteria, and vascular endothelial growth factor (VEGF), not an antibody, is considered a reliable diagnostic marker that also mirrors therapy response. As with the paraneoplastic neurologic syndromes in solid tumors, therapies rely on cancer treatment associated with immunomodulatory treatment with better response in PNS with antibodies to surface antigens. The best outcome is generally present in Ophelia syndrome/limbic encephalitis with anti-mGluR5 antibodies, with frequent complete recovery. Besides patients with isolated osteosclerotic lesions (where radiotherapy is indicated), hematopoietic stem-cell transplantation is the therapy of choice in patients with POEMS syndrome. In the paraneoplastic neurologic syndromes secondary to immune checkpoint inhibitors, discontinuation of the drug together with immunomodulatory treatment is recommended.

Paraproteinemic Neuropathies

OBJECTIVE

Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical, electrophysiologic, and hematologic phenotypes of the paraproteinemic neuropathies and the diagnostic and treatment strategies for each.

LATEST DEVELOPMENTS

Advances in our understanding of the underlying pathophysiology of various paraproteinemic neuropathies and their corresponding phenotypes have identified potential new therapeutic targets. Therapeutic strategies to diminish anti-myelin-associated glycoprotein (MAG) IgM antibodies have shown partial and inconsistent efficacy; however, antigen-specific immune therapy is being investigated as a novel treatment to remove the presumably pathogenic anti-MAG antibody. Advances in genetic and cell signaling studies have resulted in the approval of Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia. Monoclonal antibodies are being investigated for the treatment of light chain amyloidosis.

ESSENTIAL POINTS

Early recognition and treatment of underlying plasma cell disorders improves clinical outcomes in patients with paraproteinemic neuropathy. Despite significant progress, our knowledge regarding underlying mechanisms for paraproteinemic neuropathy is still limited. Clinicians' awareness of clinical phenotypes, electrophysiologic hallmarks, and hematologic findings of the different paraproteinemic neuropathies is crucial to promptly identify and treat patients and to avert misdiagnosis. Multidisciplinary collaboration among specialists, including neurologists and hematologists, is paramount for the optimal treatment of these patients with overlapping conditions.

Bruton tyrosine kinase inhibitors: can they be optimized for the treatment of neuroinflammatory disorders?

INTRODUCTION

Bruton's tyrosine kinase (BTK) is a multifaceted player of the immune system which has been involved in the survival of hematological malignancies but also in the pathogenesis of immune-mediated diseases. Oral BTK inhibitors (BTKi) have become a cornerstone for the treatment of patients with B-cell malignancies, and are under investigation for several immune-mediated diseases.

AREAS COVERED

We reviewed the biology of BTK and emerging data on BTKi in patients with neuroinflammatory disorders of both the peripheral and central nervous system.

EXPERT OPINION

We support the use of BTKi in relapsed/refractory patients with multiple sclerosis and anti-MAG antibody neuropathies. However, other immune-mediated neuroinflammatory disorders are likely to benefit from BTKi. Whether BTKi will improve the response rates than conventional therapies in previously untreated patients is unknown and will be assessed within future clinical trials. Furthermore, the availability of more selective BTKi, with less adverse events, will improve patients' tolerability and expand our treatment landscape.

Mutational Profile in 75 Patients With Anti-Myelin-Associated Glycoprotein Neuropathy: Clinical and Hematologic Therapy Response and Hints on New Therapeutic Targets

BACKGROUND AND OBJECTIVES

Neuropathy with antibodies to myelin-associated glycoprotein (MAG) is the most common paraproteinemic IgM neuropathy. Recently, the mutational profile of the MYD88 and CXCR4 genes has been included in the diagnostic workup of IgM monoclonal gammopathies. The objective of our study was to assess the prevalence of MYD88 L265P and CXCR4 S338X gene variants in patients with anti-MAG antibody neuropathy. Secondary aims were to evaluate possible correlations between the mutational profile and neuropathy severity, antibody titers, and treatment response.

METHODS

Seventy-five patients (47 men, mean age at molecular analysis 70.8 ± 10.2 years; mean disease duration 5.1 ± 4.9 years) with anti-MAG antibody neuropathy were recruited. Among them, 38 (50.7%) had IgM monoclonal gammopathy of undetermined significance, 29 (38.7%) Waldenstrom macroglobulinemia (WM), and 8 (10.6%) chronic lymphocytic leukemia/marginal zone lymphoma/hairy cell leukemia variant. Molecular analysis was performed on DNA from the bone marrow mononuclear cells in 55 of 75 patients and from peripheral mononuclear cells in 18 of 75 patients. Forty-five patients were treated with rituximab, 6 with ibrutinib, 2 with obinutuzumab-chlorambucil, and 3 with venetoclax-based therapy. All the patients were assessed with the Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Scale, INCAT Sensory Sum Score, and MRC Sum Score at baseline and follow-up. We considered as responders, patients who improved by at least 1 point in 2 clinical scales.

RESULTS

Fifty patients (66.7%) carried the MYD88L265P variant, with a higher frequency in WM and naive patients (77.2% vs 33.3%, p = 0.0012). No patients harbored the CXCR4S338X variant. There were no significant differences in hematologic data (IgM levels, M protein, and anti-MAG antibody titers), neuropathy severity, or response to rituximab in MYD88-altered and MYD88 wild-type patients. Nine of 11 (81.8%) patients treated with novel targeted drug, according to the MYD88 status, responded to treatments.

DISCUSSION

MYD88L265P variant has a high prevalence (66.7%) in anti-MAG antibody neuropathy representing a potential effective mutational target for Bruton tyrosine kinase inhibitors. MYD88L265P variant, however, does not seem to be a prognostic factor of neuropathy severity or response to rituximab. In patients not responding or becoming refractory to rituximab, a tailored therapy with new effective target therapies should be considered.

Utility of nerve ultrasound in the management of primary neurolymphomatosis: Case report and review of the literature

Introduction

Primary neurolymphomatosis (NL) is a critical differential diagnosis of asymmetric multiple mononeuropathy and radiculoplexopathy. Its diagnosis is often challenging due to the lack of typical clinical signs of systemic lymphoma. We report a case of primary NL where nerve ultrasound (NUS) played an important role in the diagnosis and follow-up of the disease.

Case presentation

A 52-year-old man developed asymmetric painful multiple mononeuropathy in the right upper limb with cranial nerve involvement. After being referred to our department, the patient underwent NUS, which revealed marked enlargement and increased vascularity in the right upper limb nerves, brachial plexus, and cervical nerve roots. Furthermore, an epineural hypoechoic mass, a characteristic finding of NL, was seen in the right median nerve. These NUS findings prompted us to perform 18F-fluorodeoxyglucose positron emission tomography/computed tomography and a subsequent biopsy on the right axillary lymph node, confirming NL. Notably, the NUS abnormalities dramatically subsided, demonstrating the effectiveness of chemotherapy.

Discussion

The diagnostic utility of NUS for NL has been documented by many recent reports. Additionally, NUS can work as a quick follow-up tool for NL, as seen in our case.

Neurolymphomatosis: involvement of peripheral nervous system revealing hematologic malignancy, a report of nine cases

BACKGROUND AND AIM

Neurolymphomatosis is defined as an infiltration of the peripheral nervous system (PNS) by malignant lymphoma cells. It is a rare entity and diagnosis is complicated especially when PNS involvement is the initial and leading symptom. To improve knowledge of the disorder and shorten the time to diagnosis, we report a series of nine patients without a history of hematologic malignancy, who were diagnosed with neurolymphomatosis after evaluation and workup of peripheral neuropathy.

METHODS

The patients were included from the Department of Clinical Neurophysiology at Pitié Salpêtrière and Nancy Hospitals over a period of 15 years. Diagnosis of neurolymphomatosis was confirmed by histopathologic examination for each patient. We characterized their clinical, electrophysiological, biological, imaging, and histopathologic features.

RESULTS

The neuropathy was characterized by pain (78%), proximal involvement (44%) or of all four limbs (67%), asymmetrical or with multifocal distribution (78%), abundant fibrillation (78%), a tendency to worsen rapidly, and significant associated weight loss (67%). Neurolymphomatosis was diagnosed principally on nerve biopsy (89%) identifying infiltration of lymphoid cells, atypical cells (78%), a monoclonal population (78%), and supported by fluorodeoxyglucose-positron emission tomography, spine or plexus MRI, cerebrospinal fluid analysis, and blood lymphocyte immunophenotyping. Six patients had systemic disease and three impairment limited to the PNS. In the latter case, progression could be unpredictable and may be diffuse and explosive, sometimes occurring years after a seemingly indolent course.

INTERPRETATION

This study provides better knowledge and understanding of neurolymphomatosis when neuropathy is the initial presentation.

A Case Series of Neurolymphomatosis: Role of Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Scan Reiterated

Neurolymphomatosis is rarely encountered in high-grade lymphomas. In this case series, we retrospectively analyzed six neurolymphomatosis cases to look for possible risk factors, common and uncommon presentations, and the lessons learned. Neuropathic pain was the most common symptom with mono or polyradiculopathy in this series. However, all lymphomatous infiltrated nerves diagnosed on fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) were not symptomatic. The lumbar, brachial plexus, and trigeminal nerve were the most common sites and were depicted well on FDG PET/CT. Magnetic resonance imaging (MRI) of the brain better delineates cranial nerves and meningeal involvement. Cerebrospinal fluid flow cytometry was normal until meninges were involved. FDG PET/CT incrementally evaluated extra-neural disease sites, thus helping in deciding biopsy sites and further management. We concluded that a whole-body FDG PET/CT including limbs with MRI brain was the appropriate investigation for evaluating suspected neurolymphomatosis in advanced-stage diffuse large B-cell lymphoma.

Update on therapy of chronic immune-mediated neuropathies

Chronic immune-mediated neuropathies, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), neuropathies associated with monoclonal gammopathy, and multifocal motor neuropathy (MMN), are a group of disorders deemed to be caused by an immune response against peripheral nerve antigens. Several immune therapies have been reported to be variably effective in these neuropathies including steroids, plasma exchange, and high-dose intravenous (IVIg) or subcutaneous (SCIg) immunoglobulins. These therapies are however far from being invariably effective and may be associated with a number of side effects leading to the use of immunosuppressive agents whose efficacy has not been so far confirmed in randomized trials. More recently, new biological agents, such as rituximab, have proved to be effective in patients with neuropathy associated with IgM monoclonal gammopathy and are currently tested in CIDP.

Clinical Reasoning: A 65-Year-Old Woman With Cancer History and Wrist Drop

Wrist drop is a common presentation in neurology. To localize the lesion, clinicians can focus on testing finger extension, elbow flexion with semipronated forearm, and elbow extension among other muscle groups and identifying dermatomes of numbness. Once the lesion is localized, electrophysiology or imaging can guide to an underlying etiology. Here, we describe a case that illustrates the importance of using a stepwise approach to diagnose the etiology of wrist drop in a patient with a cancer history. A 65-year-old woman with diffuse large B-cell lymphoma in remission presented with new onset wrist drop, severe pain, numbness, and tingling concerning for peripheral nerve injury. Imaging findings from PET, venous ultrasound, nerve conduction velocity study, and MRI were conflicting favoring deep venous thrombosis, cancer recurrence, or peripheral nerve sheath tumor. A biopsy was ultimately required to confirm the diagnosis.

Clinical and pathological findings in neurolymphomatosis: Preliminary association with gene expression profiles in sural nerves

Although inflammation appears to play a role in neurolymphomatosis (NL), the mechanisms leading to degeneration in the peripheral nervous system are poorly understood. The purpose of this exploratory study was to identify molecular pathways underlying NL pathogenesis, combining clinical and neuropathological investigation with gene expression (GE) studies. We characterized the clinical and pathological features of eight patients with NL. We further analysed GE changes in sural nerve biopsies obtained from a subgroup of NL patients (n=3) and thirteen patients with inflammatory neuropathies as neuropathic controls. Based on the neuropathic symptoms and signs, NL patients were classified into three forms of neuropathy: chronic symmetrical sensorimotor polyneuropathy (SMPN, n=3), multiple mononeuropathy (MN, n=4) and acute motor-sensory axonal neuropathy (AMSAN, n=1). Predominantly diffuse malignant cells infiltration of epineurium was present in chronic SMPN, whereas endoneurial perivascular cells invasion was observed in MN. In contrast, diffuse endoneurium malignant cells localization occurred in AMSAN. We identified alterations in the expression of 1266 genes, with 115 up-regulated and 1151 down-regulated genes, which were mainly associated with ribosomal proteins (RP) and olfactory receptors (OR) signaling pathways, respectively. Among the top up-regulated genes were actin alpha 1 skeletal muscle (ACTA1) and desmin (DES). Similarly, in NL nerves ACTA1, DES and several RPs were highly expressed, associated with endothelial cells and pericytes abnormalities. Peripheral nerve involvement may be due to conversion towards a more aggressive phenotype, potentially explaining the poor prognosis. The candidate genes reported in this study may be a source of clinical biomarkers for NL.

The BCL2 Inhibitor Venetoclax Plus Rituximab Is Active in MYD88 Wild-Type Polyneuropathy With Anti-MAG Antibodies

OBJECTIVES

Ibrutinib is active in anti-myelin-associated glycoprotein (MAG) polyneuropathy with MYD88^L265P mutation; however, its efficacy is likely to be low in MYD88 wild-type patients. Venetoclax, an oral inhibitor of BCL2, in combination with rituximab is highly active in ibrutinib-resistant hematologic malignancies. We report on the first patient with anti-MAG polyneuropathy and MYD88 wild-type who responded to venetoclax-rituximab.

METHODS

A 62-year-old woman with chronic lymphocytic leukemia had IgM/K anti-MAG neuropathy. She needed bilateral support to walk outdoors, despite therapy with rituximab/cyclophosphamide. Tremor and symptoms at arms prevented her capability of performing common tasks. Bone marrow genetic showed lack of MYD88 mutation. Venetoclax was given orally starting from 20 mg up to 400 mg for 24 months. Rituximab was administrated IV, after the ramp-up phase, at 375 mg/m² for the second month and then monthly at 500 mg/m² for months 3-7.

RESULTS

After 12 months of venetoclax IgM levels decreased from 1.16 to 0.52 g/L, the paraproteins became undetectable and anti-MAG antibody titer decreased. The patient regained the capability of walking independently. Tremor disappeared, she is back able to write and knitt.

DISCUSSION

The first patient with anti-MAG neuropathy treated with venetoclax-rituximab shows encouraging results.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for a patient with relapsed anti-MAG antibody polyneuropathy, MYD88 wild-type, venetoclax plus rituximab is effective.

Sciatic and median nerve neurolymphomatosis as initial presentation of B-cell lymphoma

Neurolymphomatosis (NL) is the infiltration of cranial nerves or nerves and roots from the peripheral nervous system by lymphoma, usually by B-cell non-Hodgkin's lymphoma. It is uncommon as initial presentation of the disease and can lead to extremely heterogeneous clinical manifestations. We report the case of a 72-year old male who presented with numbness of the right hand, progressive weakness in both lower limbs and weight loss. 18F-FDG PET/CT showed bilateral hypermetabolic adrenal masses, gastric ulcer, small hypermetabolic adenopathies, multiple focal bone marrow uptake and intense uptake in both sciatic nerves and right median nerve. A node and gastric biopsy confirmed diffuse large-B-cell lymphoma, activated B cell type, with posterior resolution of peripheral nerves uptake after beginning chemotherapy.

Chronic demyelinating polyneuropathy preceding T-cell lymphoma: differentiation between primary neurolymphomatosis and paraneoplastic neuropathy

A 49-year-old man presented with progressive asymmetric weakness and pain. Electrodiagnostic tests and nerve biopsy suggested chronic demyelinating polyneuropathy refractory to immune-modulating therapy. The patient's symptoms were aggravated, and he was finally diagnosed with T-cell lymphoma based on the findings of the second 18F-2 fluoro-2-deoxy-glucose positron emission tomography/CT performed 16 months after symptom onset. The patient received intravenous chemotherapy, but died 2 months later because of lymphoma progression. A clinical suspicion of neurolymphomatosis and early diagnosis are important for proper management.

From Biology to Treatment of Monoclonal Gammopathies of Neurological Significance

Monoclonal gammopathy and peripheral neuropathy are common diseases of elderly patients, and almost 10% of patients with neuropathy of unknown cause have paraprotein. However, growing evidence suggests that several hematological malignancies synthesize and release monoclonal proteins that damage the peripheral nervous system through different mechanisms. The spectrum of the disease varies from mild to rapidly progressive symptoms, sometimes affecting not only sensory nerve fibers, but also motor and autonomic fibers. Therefore, a multidisciplinary approach, mainly between hematologists and neurologists, is recommended in order to establish the correct diagnosis of monoclonal gammopathy of neurological significance and to tailor therapy based on specific genetic mutations. In this review, we summarize the spectrum of monoclonal gammopathies of neurological significance, their distinctive clinical and neurophysiological phenotypes, the most relevant pathophysiological events and new therapeutic approaches.

Neurolymphomatosis related to direct epineural invasion of the superficial peroneal nerve from subcutaneous B-cell lymphoma

Neurolymphomatosis is a rare complication of systemic lymphomas, and is classically related to hematogenous spread or intraneural spread of tumor cells from the leptomeninges. Here we report a case of neurolymphomatosis related to direct epineural invasion of the superficial peroneal nerve from subcutaneous localization of B-cell lymphoma. Nerve biopsy revealed striking histological features suggestive of contiguous infiltration of the superficial peroneal nerve by subcutaneous lymphoma. We think this case report sheds new light on neurolymphomatosis pathophysiology with an unreported mechanism in B-cell lymphoma. It also points out that the clinical spectrum in neurolymphomatosis is really variable, pure sensory mononeuritis being a rare presentation. Finally, our case is also strongly illustrative of the contribution of early nerve ultrasonography in the patient diagnosis and in guidance of the nerve biopsy.

Variant Median Nerve Anatomy: Ultrasound Evidence of a Pseudoconduction Block

INTRODUCTION

A conduction block at a noncompressible site warrants further investigation.

METHODS AND MATERIALS

A 36-year-old woman with a history of Hodgkin lymphoma and chemotherapy-induced polyneuropathy developed bilateral hand numbness and paresthesias. Workup revealed bilateral carpal tunnel syndrome and an apparent superimposed conduction block of the median nerve in the forearm. Given the history of cancer, there was concern for an infiltrative or an immune-mediated process.

RESULTS

Neuromuscular ultrasound demonstrated that the median nerve descended the upper extremity along an atypical path, deep along the posteromedial aspect of the upper arm, and relatively medially in the forearm. Ultrasound-directed nerve stimulation revealed there was no conduction block. This anatomical variant has been rarely described and has not been reported previously to mimic conduction block or been documented via ultrasound.

CONCLUSIONS

This case demonstrates that neuromuscular ultrasound may supplement the electrodiagnostic study and limit confounding technical factors because of rare anatomic variation.

Mechanisms of Nerve Damage in Neuropathies Associated with Hematological Diseases: Lesson from Nerve Biopsies

Despite the introduction of non-invasive techniques in the study of peripheral neuropathies, sural nerve biopsy remains the gold standard for the diagnosis of several neuropathies, including vasculitic neuropathy and neurolymphomatosis. Besides its diagnostic role, sural nerve biopsy has helped to shed light on the pathogenic mechanisms of different neuropathies. In the present review, we discuss how pathological findings helped understand the mechanisms of polyneuropathies complicating hematological diseases.

Sciatic and median nerve neurolymphomatosis as initial presentation of B-cell Lymphoma

Neurolymphomatosis (NL) is the infiltration of cranial nerves or nerves and roots from the peripheral nervous system by lymphoma, usually by B-cell non-Hodgkin's lymphoma. It is uncommon as initial presentation of the disease and can lead to extremely heterogeneous clinical manifestations. We report the case of a 72-year old male who presented with numbness of the right hand, progressive weakness in both lower limbs and weight loss. 18F-FDG PET/CT showed bilateral hypermetabolic adrenal masses, gastric ulcer, small hypermetabolic adenopathies, multiple focal bone marrow uptake and intense uptake in both sciatic nerves and right median nerve. A node and gastric biopsy confirmed diffuse large-B-cell lymphoma, activated B cell type, with posterior resolution of peripheral nerves uptake after beginning chemotherapy.

Perineural spread to the brachial plexus: a focused review of proposed mechanisms and described pathologies

BACKGROUND

Perineural spread (PNS) is an emerging mechanism for progressive, non-traumatic brachial plexopathy. We aim to summarize the pathologies (tumor and infection) shown to have spread along or to the brachial plexus, and identify the proposed mechanisms of perineural spread.

METHODS

A focused review of the literature was performed pertaining to pathologies with identified perineural spread to the brachial plexus.

RESULTS

We summarized pathologies currently reported to have PNS in the brachial plexus and offer a structure for understanding and describing these pathologies with respect to their interaction with the peripheral nervous system.

CONCLUSIONS

Perineural spread is an underrepresented entity in the literature, especially regarding the brachial plexus. It can occur via a primary or secondary mechanism based on the anatomy, and understanding this mechanism helps to support biopsies of sacrificial nerve contributions, leading to more effective and timely treatment plans for patients.

Frequency of diabetes and other comorbidities in chronic inflammatory demyelinating polyradiculoneuropathy and their impact on clinical presentation and response to therapy

OBJECTIVES

To determine the prevalence of different comorbidities in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and their impact on outcome, treatment choice and response.

METHODS

Using a structured questionnaire, we collected information on comorbidities from 393 patients with CIDP fulfilling the European Federation of Neurological Societies and Peripheral Nerve Society criteria included in the Italian CIDP database.

RESULTS

One or more comorbidities were reported by 294 patients (75%) and potentially influenced treatment choice in 192 (49%) leading to a less frequent use of corticosteroids. Response to treatment did not differ, however, from that in patients without comorbidities. Diabetes (14%), monoclonal gammopathy of undetermined significance (MGUS) (12%) and other immune disorders (16%) were significantly more frequent in patients with CIDP than expected in the general European population. Patients with diabetes had higher disability scores, worse quality of life and a less frequent treatment response compared with patients without diabetes. Patients with IgG-IgA or IgM MGUS had an older age at CIDP onset while patients with other immune disorders had a younger age at onset and were more frequently females. IgM MGUS was more frequent in patients with motor CIDP than in patients with typical CIDP.

CONCLUSIONS

Comorbidities are frequent in patients with CIDP and in almost 50% of them have an impact on treatment choice. Diabetes, MGUS and other immune diseases are more frequent in patients with CIDP than in the general population. Only diabetes seems, however, to have an impact on disease severity and treatment response possibly reflecting in some patients a coexisting diabetic neuropathy.

From pathogenesis to personalized treatments of neuropathies in hematological malignancies

The peripheral nervous system may be involved at any stage in the course of several hematological diseases, the most common being monoclonal gammopathies (of undetermined significance or malignant) or lymphomas. The underlying pathogenic mechanisms are different and therapies aim at targeting the dangerous either B-cell or plasma cell clones. Recently, high-throughput technologies, and next-generation sequencing have increased our knowledge of hematological diseases pathogenesis by the identification of somatic mutation affecting pivotal signaling pathways. Accordingly, new target therapies are used that may also be borrowed for treatment of neuropathies in hematological diseases.

Neurolymphomatosis, a rare manifestation of peripheral nerve involvement in lymphomas: Suggestive features and diagnostic challenges

Neurolymphomatosis, the infiltration of the peripheral nervous system from lymphoid cells, represents an uncommon manifestation of lymphomas. We describe the challenging diagnostic work-up in a patient with neurolymphomatosis. A 58-year-old woman with previous breast diffuse large B-cell lymphoma treated with chemo- and radiation-therapy, presented with dysesthesias, neuropathic pain at left abdomen and thigh, and weakness at left lower limb 9 years after disease remission. Neurophysiology revealed left T10-L4 radiculo-plexopathy with no abnormalities at cerebrospinal fluid (CSF), nerve ultrasound, and ¹⁸ fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). MR-neurography disclosed left rectus abdominis muscle atrophy, neurogenic edema, and denervation. Radiation-induced damage, paraneoplastic, infectious radiculo-plexopathies, and atypical chronic inflammatory demyelinating polyradiculoneuropathy were ruled out. Neurolymphomatosis was suspected, and the patient treated with rituximab with improvement. Despite treatment, the radiculo-plexopathy eventually extended to the right side and sacral roots. Later in the disease course, sural nerve biopsy confirmed the diagnosis. Maintenance therapy was continued, until cutaneous localizations occurred, requiring salvage therapy and autologous stem cell transplant. Although rare, neurolymphomatosis should be considered in all patients with lymphomas and unexplained peripheral nervous system involvement. Hematological, CSF, and neuroimaging findings may be unremarkable, and a high index of suspicion required in order to achieve the diagnosis.

Sural nerve biopsy: current role and comparison with serum neurofilament light chain levels

The diagnosis of peripheral neuropathies can be challenging with consequent difficulties in patients' management. The aim of this study was to explore the current diagnostic role of sural nerve biopsy and to compare pathological findings with serum neurofilament light chain levels (NfL) as biomarkers of axonal damage. We collected demographic, clinical, and paraclinical data of patients referred over 1 year to the Neurology Unit, University of Verona, Italy, to perform nerve biopsy for diagnostic purposes, and we analyzed NfL levels in available paired sera using a high sensitive technique (Quanterix, Simoa). Eighty-two patients were identified (37.8% females, median age 65.5 years). Neuropathy onset was frequently insidious (68.3%) with a slowly progressive course (76.8%). Lower limbs were usually involved (81.7%), with a predominance of sensory over motor symptoms (74.4% vs 42.7%). The most common neuropathological findings were a demyelinating pattern (76.8%), clusters of regenerations (58.5%), and unmyelinated fibers involvement on ultrastructural evaluation (52.4%). A definite pathological diagnosis was achieved in 29 cases, and in 20.7% of patients, the referral clinical diagnosis was modified. Coexistent hematological conditions and hepatitis were diagnostic confounding factors (p = 0.012 and 0.034, respectively). In the analyzed paired sera (n = 37), an inverse despite not significant relationship between NfL values and fiber density was observed (Spearman's rho - 0.312, p = 0.056). In addition, we noted increased serum NfL values of patients with active axonal degeneration. Nerve biopsy remains a useful diagnostic investigation to achieve a correct diagnosis and guide patients' management in selected cases of peripheral neuropathy. Serum NfL is an accessible and potential valuable marker of axonal damage in these conditions.

Diffuse large B-cell lymphoma relapse presenting as extensive neurolymphomatosis

A 56-year-old woman with a history of diffuse large B-cell non-Hodgkin lymphoma (DLBCL-NHL) in remission for two years presented with weight loss and multifocal sensory/motor symptoms. Magnetic resonance imaging (MRI) of the neuraxis and whole-body FDG PET/CT led to a diagnosis of secondary neurolymphomatosis (NL). MRI demonstrated extensive thickening and enhancement of multiple cranial nerves and peripheral nerve plexuses with corresponding elevated metabolism on FDG PET/CT. Treatment with chemotherapy resulted in complete response on FDG PET/CT and subsequently she underwent autologous stem cell transplantation. NL is a rare manifestation of lymphoma affecting the peripheral nervous system. Nonspecific neuropathic symptoms make clinical diagnosis difficult. Though nerve biopsy is considered the gold standard, MRI and FDG PET/CT are accepted alternatives for making the diagnosis. We review imaging findings in NL, describe the differential diagnosis, and discuss the limitations of the imaging modalities.

The Bruton tyrosine kinase inhibitor ibrutinib improves anti-MAG antibody polyneuropathy

Objective

To assess whether neuropathy with anti-myelin-associated glycoprotein (MAG) antibody may improve after treatment with ibrutinib, an oral inhibitor of Bruton tyrosine kinase, we prospectively treated with ibrutinib a cohort of 3 patients with anti-MAG neuropathy and Waldenström macroglobulinemia (WM).

Methods

All 3 patients underwent bone marrow biopsy showing WM, with MYD88^L265P mutated and CXCR4^S338X wild type, and were started on ibrutinib 420 mg/die. Patients were assessed at baseline, at 3-6-9 months, and at 12 months in 2 patients with a longer follow-up, using Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Score, INCAT sensory sum score, and Medical Research Council sum score. The modified International Cooperative Ataxia Rating Scale was performed in 2 patients, whereas it was not used in the patient with Parkinson disease as a major comorbidity. Responders were considered the patients improving by at least one point in 2 clinical scales.

Results

All the patients reported an early and subjective benefit, consistent with the objective improvement, especially of the sensory symptoms as shown by clinical scales. Treatment was well tolerated.

Conclusion

These preliminary data point to a possible efficacy of ibrutinib in anti-MAG antibody neuropathy, which is the most common disabling paraproteinemic neuropathy, where active treatment is eagerly needed.

Classification of evidence

This study provides Class IV evidence that for patients with anti-MAG antibody neuropathy, ibrutinib improves neuropathy symptoms.

Recurrence of nasal type NK/T cell lymphoma presenting as neurolymphomatosis on 18F-FDG PET/CT: A case report and literature review

INTRODUCTION

NK/T cell lymphomas seldom involve the peripheral nervous system. We report a case of recurrent nasal type NK/T cell lymphoma presenting as neurolymphomatosis and its manifestation on F-FDG PET/CT.

PATIENT CONCERNS

A 55-year old man presented with a mass in the right nasal cavity was diagnosed with extranodal NK/T cell lymphoma, nasal type. F-FDG PET/CT showed intense FDG uptake within the mass. After radiotherapy the nasal tumor was completely relieved, but the patient experienced numbness and amyosthenia in the right upper extremity one week after completion of radiotherapy.

DIAGNOSIS

PET/CT showed intense FDG uptake in the brachial plexus, axillary, suprascapular and median nerves, suggestive of recurrence of lymphoma presenting as neurolymphomatosis.

INTERVENTIONS

After 1 cycle of chemotherapy, the follow-up PET/CT showed markedly reduced FDG uptake in the previous involved nerves, demonstrating a very good response of neurolymphomatosis to chemotherapy.

OUTCOMES

The patient finally had a progression free survival of 8 months after completion of 4 cycles of chemotherapy and autologous stem cell transplantation.

LESSONS

As neurolymphomatosis is a rare neurologic manifestation in recurrence of NK/T cell lymphoma, recognition of its presentation is important for prompt diagnosis and initiating treatment approach.

Secondary Neurolymphomatosis of the Radial Nerve: A Diagnostic Challenge

BACKGROUND Secondary neurolymphomatosis is a rare clinical condition that may be observed in patients with hematologic malignancies. Clinical findings can overlap with other conditions. Diagnosis can be obtained by magnetic resonance imaging (MRI) and imaging with positron emission tomography (PET) and confirmed by biopsy. CASE REPORT A 55-year-old male patient with known previous history of periocular non-Hodgkin's lymphoma mucosa-associated lymphoid tissue (MALT) type presented reporting he had a focal soft-tissue swelling mass on the external side of the right arm, suspected for lipoma. US, MRI, and FDG PET/CT were performed, revealing malignant imaging characteristics of the lesion, suspected to be a neurolymphoma. A biopsy confirmed the nature of the lesion. No further sites of malignancy were detected on whole-body PET/CT. CONCLUSIONS Lymphomatous involvement of peripheral nerves may clinically overlap with other, more common, benign conditions; therefore, although it is rarer, this diagnosis has to be considered in patients with a clinical history of hematologic malignancies.