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.

Neurosurgical Intervention for Nerve and Muscle Biopsies

(1) Background: Neurologic and musculoskeletal diseases represent a considerable portion of the underlying etiologies responsible for the widely prevalent symptoms of pain, weakness, numbness, and paresthesia. Because of the subjective and often nonspecific nature of these symptoms, different diagnostic modalities have been explored and utilized. (2) Methods: Literature review. (3) Results: Nerve and muscle biopsy remains the gold standard for diagnosing many of the responsible neurological and musculoskeletal conditions. However, the need for invasive tissue sampling is diminishing as more investigations explore alternative diagnostic modalities. Because of this, it is important to explore the current role of neurosurgical intervention for nerve and muscle biopsies and its current relevance in the diagnostic landscape of neurological and musculoskeletal disorders. With consideration of the role of nerve and muscle biopsy, it is also important to explore innovations and emerging techniques for conducting these procedures. This review explores the indications and emerging techniques for neurological intervention for nerve and muscle biopsies. (4) Conclusions: The role of neurosurgical intervention for nerve and muscle biopsy remains relevant in diagnosing many neurological and musculoskeletal disorders. Biopsy is especially relevant as a supportive point of evidence for diagnosis in atypical cases. Additionally, emerging techniques have been explored to guide diagnostics and biopsy, conduct less invasive biopsies, and reduce risks of worsening neurologic function and other symptoms secondary to biopsy.

Neurolymphomatosis diagnosed after a recurrence of facial palsy

Neurolymphomatosis (NL) is a rare complication of non-Hodgkin's lymphoma, characterized by the infiltration of lymphoma cells into the peripheral nerves. A 54-year-old woman initially presented with right facial palsy without any other significant symptoms and was diagnosed with Bell's palsy. Despite initial improvement, her condition recurred, prompting further evaluation. Magnetic resonance imaging (MRI) revealed contrast enhancement from the tympanic segment to the surface of the masseter muscle along the right facial nerve and an adjacent mass lesion. Biopsy of the mass revealed a diagnosis of T-cell/histiocyte-rich large B-cell lymphoma. Chemotherapy resulted in complete resolution of facial palsy. Follow-up MRI confirmed the absence of contrast enhancement along the facial nerve. Facial palsy was considered to be caused by NL. This case was classified as that of primary NL because the facial palsy was the first manifestation of a hematologic malignancy. Recurrent facial palsy, which is atypical in Bell's palsy, led to further evaluation with MRI, which finally resulted in the diagnosis of malignant lymphoma. In cases of recurrent facial palsy, clinicians should consider various diagnoses, including that of NL, and advocate early imaging tests and biopsy, if possible, for accurate diagnosis and improved outcomes.

Primary perineuritis, a rare but treatable neuropathy: Review of perineurial anatomy, clinicopathological features, and differential diagnosis

The perineurium surrounds each fascicle in peripheral nerves, forming part of the blood-nerve barrier. We describe its normal anatomy and function. "Perineuritis" refers to both a nonspecific histopathological finding and more specific clinicopathological entity, primary perineuritis (PP). Patients with PP are often assumed to have nonsystemic vasculitic neuropathy until nerve biopsy is performed. We systematically reviewed the literature on PP and developed a differential diagnosis for histopathologically defined perineuritis. We searched PubMed, Embase, Scopus, and Web of Science for "perineuritis." We identified 20 cases (11 M/9F) of PP: progressive, unexplained neuropathy with biopsy showing perineuritis without vasculitis or other known predisposing condition. Patients ranged in age from 18 to 75 (mean 53.7) y and had symptoms 2-24 (median 4.5) mo before diagnosis. Neuropathy was usually sensory-motor (15/20), painful (18/19), multifocal (16/20), and distal-predominant (16/17) with legs more affected than arms. Truncal numbness occurred in 6/17; 10/18 had elevated cerebrospinal fluid (CSF) protein. Electromyography (EMG) and nerve conduction studies (NCS) demonstrated primarily axonal changes. Nerve biopsies showed T-cell-predominant inflammation, widening, and fibrosis of perineurium; infiltrates in epineurium in 10/20 and endoneurium in 7/20; and non-uniform axonal degeneration. Six had epithelioid cells. 19/20 received corticosteroids, 8 with additional immunomodulators; 18/19 improved. Two patients did not respond to intravenous immunoglobulin (IVIg). At final follow-up, 13/16 patients had mild and 2/16 moderate disability; 1/16 died. Secondary causes of perineuritis include leprosy, vasculitis, neurosarcoidosis, neuroborreliosis, neurolymphomatosis, toxic oil syndrome, eosinophilia-myalgia syndrome, and rarer conditions. PP appears to be an immune-mediated, corticosteroid-responsive disorder. It mimics nonsystemic vasculitic neuropathy. Cases with epithelioid cells might represent peripheral nervous system (PNS)-restricted forms of sarcoidosis.

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.

[Nerve biopsy in the diagnosis of peripheral neuropathies]

The indications for nerve biopsy have diminished in recent years. This examination nevertheless remains essential in certain cases of peripheral neuropathies, making it possible to specify the diagnosis or the mechanism of injury for a therapeutic purpose. It is a simple but "invasive" procedure, which can only be performed once on the same nerve. The indications are thus discussed on a case-by-case basis and based on a range of clinical, electrophysiological, biological or even genetic arguments. This involves close collaboration between clinical physicians and pathologists. The main difficulty of this biopsy concerns the fragility of the sample and the techniques necessary for its interpretation, requiring it to be carried out in expert centers. Nerve biopsy is closely related to skin biopsy in the search for small fiber neuropathy. It is a particular technique, but very well codified. The purpose of this review is to recall the indications and contraindications of nerve biopsy, and to explain what the contributions are but also the limits of this examination as well as of skin biopsy.

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.

Neoplastic nerve lesions

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

CIDP and hemopathies, an underestimated association

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated and treatable disease that may be associated with various systemic conditions. Our objective is to describe the clinical, electrophysiological and pathological data of a series of patients with both CIDP and hemopathy. In this retrospective study, we analyzed 21 patients with CIDP and various hemopathies (malignant or not), consecutively observed for almost five years. In this particular context (with a risk of neurological complications of the hemopathy), a nerve biopsy was taken from each patient (after written consent). All the patients fulfilled the EAN/PNS electrodiagnostic criteria (2021) of CIDP: 16 with 'CIDP' and 2 with 'possible CIDP' (no data for 3 patients). For each patient, pathological analysis of nerve biopsy was compatible with the diagnosis of CIDP, and there was no evidence for hematological complication of the peripheral nervous system. In cases of peripheral neuropathy and malignant hemopathy, the possibility that the peripheral neuropathy is CIDP should not be overlooked because CIDP is clearly accessible to appropriate therapies, with high potential for a positive clinical response. If the diagnosis of CIDP is usually suspected clinically and electrophysiologically, it should be confirmed by pathological study (nerve biopsy) in certain cases. The management of such patients benefits from the collaboration of neurologists, hematologists and oncologists.

Nerve biopsy in acquired neuropathies

A diagnosis of neuropathy can typically be determined through clinical assessment and focused investigation. With technological advances, including significant progress in genomics, the role of nerve biopsy has receded over recent years. However, making a specific and, in some cases, tissue-based diagnosis is essential across a wide array of potentially treatable acquired peripheral neuropathies. When laboratory investigations do not suggest a definitive diagnosis, nerve biopsy remains the final step to ascertain the etiology of the disease. The present review highlights the utility of nerve biopsy in confirming a diagnosis, while further illustrating the importance of a tissue-based diagnosis in relation to treatment strategies, particularly when linked to long-term immunosuppressive therapies.

Nerve biopsy: Current indications and decision tools

After initial investigation of patients presenting with symptoms suggestive of neuropathy, a clinical decision is made for a minority of patients to undergo further assessment with nerve biopsy. Many nerve biopsies do not demonstrate a definitive pathological diagnosis and there is considerable cost and morbidity associated with the procedure. This highlights the need for appropriate selection of patients, nerves and neuropathology techniques. Additionally, concomitant muscle and skin biopsies may improve the diagnostic yield in some cases. Several advances have been made in diagnostics in recent years, particularly in genomics. The indications for nerve biopsy have consequently changed over time. This review explores the current indications for nerve biopsies and some of the issues surrounding its use. Also included are comments on alternative diagnostic modalities that may help to supplant or reduce the use of nerve biopsy as a diagnostic test. These primarily include extraneural biopsy and neuroimaging techniques such as magnetic resonance neurography and nerve ultrasound. Finally, we propose an algorithm to assist in deciding when to perform nerve biopsies.

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.

The Wide Spectrum of Pathophysiologic Mechanisms of Paraproteinemic Neuropathy

Monoclonal gammopathy is encountered quite frequently in the general population. This type of hematologic abnormality may be mild, referred to as monoclonal gammopathy of undetermined significance or related to different types of hematologic malignancies. The association of a peripheral neuropathy with monoclonal gammopathy is also fairly common, and hemopathy may be discovered in an investigation of peripheral neuropathy. In such a situation, it is essential to determine the exact nature of the hematologic process in order not to miss a malignant disease and thus initiate the appropriate treatment (in conjunction with hematologists and oncologists). In this respect, nerve biopsy (discussed on a case-by-case basis) is of great value in the management of such patients. We therefore propose to present the objectives and main interests of nerve biopsy in this situation.

Peripheral nerve neurolymphomatosis: Clinical features, treatment, and outcomes

This series characterises nine patients with neurohistopathologically proven peripheral nerve neurolymphomatosis. A search of the hospital neuropathology database from 2002 to 2019 identified biopsy proven cases. Clinical data, investigation modalities, treatments, and outcomes were collated. Median age at neuropathy onset was 47 y, the neuropathy commonly as the initial lymphoma disease manifestation. Most (8/9) presented with painful asymmetrical sensory disturbance, with additional cranial nerve involvement in three. Neurophysiology typically demonstrated multiple axonal mononeuropathies. Cerebrospinal fluid protein was often raised (6/8). Magnetic resonance imaging suggested peripheral nerve infiltration in 6/9 and positron emission tomography CT in 4/9. Bone marrow biopsy was abnormal in 6/8. Treatment involved systemic or intrathecal chemotherapy and radiotherapy. Median survival was 23 mo. Neurolymphomatosis is a rare but important cause of neuropathy, particularly in those lacking systemic evidence of lymphoma as correct aggressive treatment can prolong survival. Nerve biopsy is essential to classify lymphoma type and rule out alternatives.

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.

Diagnostic delay in a case of T-cell neurolymphomatosis

A 69-year-old woman presented with severe subacute painful meningoradiculoneuritis. Neurophysiology showed a patchy, proximal axonal process with widespread denervation. Cerebrospinal fluid (CSF) was lymphocytic (normal T-cell predominant) with negative cytology. MRI revealed multiple sites of enhancement, but fluorodeoxyglucose positron emission tomography was negative. Bone marrow aspirate and trephine (BMAT) showed no evidence of a lymphoproliferative condition. Right brachial plexus biopsy demonstrated mixed T-cell/B-cell endoneurial inflammation not fulfilling criteria for vasculitis. She was stabilised with high-dose steroids and cyclophosphamide, followed by mycophenolate for inflammatory myeloradiculoneuritis. However, symptoms recurred when prednisolone was weaned. Although T-cell receptor gene analysis from the initial CSF demonstrated clonal rearrangements, it was only when the same clones were identified on two repeat BMATs and CSF that T-cell neurolymphomatosis, an exceedingly rare condition, was diagnosed. This case highlights the diagnostic challenge in peripheral neurolymphomatosis related to patchy disease, variable sensitivity and specificity of investigative tools, and the influence of therapies on traditional cytological definitions of lymphoma. The clinical picture, exhaustive exclusion of alternative causes and the persistence of an abnormal T-cell clone ultimately lead to a diagnostic consensus between specialist neurology and haematology clinicians.