Paraproteinemic neuropathy

Thymic plasmacytoma presenting as polyneuropathy and revealing multiple myeloma: a case report

Background

Multiple myeloma (MM) is the most frequent malignant plasma cell disorder with proliferation of neoplastic plasma cells in the bone marrow or other tissue, most commonly in the upper aerodigestive tract. The invasion of the thymus is exceptional. Neurological complications are usual, but represent exceptionally the revealing symptom.

Case presentation

We report a case of polyneuropathy revealing a thymic plasmacytoma as a mediastinal invasion of MM in a 48-year-old woman. She was admitted after developing progressive ascending distal paresthesias and weakness in lower limbs. Examination showed symmetrical distal sensorimotor impairment with axillary and inguinal adenopathies. Electroneuromyography revealed a sensorimotor length-dependent neuropathy. Serum protein electrophoresis showed monoclonal protein peak in β-γ globulin region. Immunoelectrophoresis showed IgA lambda monoclonal gammapathy. Myelogram and bone marrow biopsy revealed plasmocytosis of 5%. Chest computed tomography showed a histologically confirmed thymic plasmacytoma associated with a lytic lesion of the 5th rib leading to the diagnosis of MM.

Conclusions

The association between a thymic plasmacytoma and peripheral neuropathy is rare and a workup for MM is necessary to guide therapeutic management.

Infiltration of the spinal cord and peripheral nerves in multiple myeloma

Background

Multiple myeloma (MM) is a hematological malignancy, and intramedullary spinal cord metastasis is extremely rare.

Methods

Clinical and radiological data were collected from electronic medical records as well as a literature review of reported cases.

Results

We report a rare case of IgA-LAM stage IIB MM with involvement of the spinal cord and peripheral nervous system. Laboratory studies showed elevated levels of serum β2-macroglobulin and cerebrospinal fluid protein. Electromyography revealed a demyelinating process with motor conduction blocks. On MRI, the lesions of MM bone marrow are characterized as a type of diffuse infiltration. MR neurography demonstrated an enhanced nodule in the thoracic segment with swelling of the cervicothoracic segments of the spinal cord. Moreover, swelling and hypertrophy of the entire nerve branchial, lumbosacral plexus, and cauda equina were detected, accompanied by myofascitis and denervated muscles. Ultimately, the condition of the patient deteriorated quickly and she died with a diagnosis of refractory MM.

Conclusion

MRI not only has the advantage of displaying the primary involved site of the bone marrow but also facilitates detecting extramedullary hematopoietic MM, such as infiltrating sites of the central and/or peripheral nervous system.

High prevalence of peripheral neuropathy in multiple myeloma patients and the impact of vitamin D levels, a cross-sectional study

PURPOSE

Peripheral neuropathy (PN) is common in patients with multiple myeloma (MM). We hypothesized that the relationship between hypovitaminosis D and PN described in diabetes mellitus patients may also be present in MM patients.

METHODS

To study this potential association, we assessed the incidence of hypovitaminosis D (vitamin D < 75 nmol/L [= 30 ng/mL]) in smouldering and active MM patients in two Dutch hospitals. Furthermore, a validated questionnaire was used to distinguish different PN grades.

RESULTS

Of the 120 patients included between January 2017 and August 2018, 84% had an inadequate vitamin D level (median vitamin D level 49.5 nmol/L [IQR 34-65 nmol/L]; mean age: 68 years [SD ± 7.7]; males: 58%). PN was reported by 69% of patients (n = 83); however, of these 83 patients, PN was not documented in the medical records of 52%. An association was found between lower vitamin D levels and higher incidence of PN in the total population (P = 0.035), and in the active MM patients (P = 0.016).

CONCLUSION

This multi-centre cohort study showed that PN and hypovitaminosis D are common in MM patients, and addressing low vitamin D levels in the treatment of MM patients might be beneficial in reducing the risk of PN. More attention for PN is warranted, as PN is underreported by clinicians. Further research is needed to fully understand the implications of vitamin D in the development of PN in patients with MM.

CLINICAL TRIAL REGISTRATION

Netherland Trial Register NL5835, date of registration July 28, 2016.

Distinctive patterns of peripheral neuropathy across the spectrum of plasma cell disorders

Many patients with plasma cell disorders suffer from peripheral neuropathy, but differential diagnosis with chronic inflammatory demyelinating polyneuropathy (CIDP) is difficult. We aimed to (1) identify factors useful for differential diagnosis between peripheral neuropathy associated with plasma cell disorders versus CIDP and (2) determine whether neuropathy presentations and severity varied across the spectrum of different plasma cell disorders. A retrospective chart review of 18 monoclonal gammopathy of unknown significance (MGUS) patients, 15 POEMS syndrome patients and 34 CIDP patients between January 2005 and December 2016 was conducted. The peripheral neuropathy associated with plasma cell disorders seemed to be more sensory oriented compared to CIDP. MGUS patients were significantly older than CIDP patients (median age 70 vs. 59, respectively, p = 0.027). POEMS syndrome patients showed significantly higher platelet count at the time of neuropathy presentation compared to CIDP (p = 0.028). Lambda type MGUS patients were associated with less severe symptoms compared to POEMS syndrome patients despite harboring lambda monoclonal gammopathy as a common denominator. Kappa type MGUS patients showed predominantly axonal type neuropathy compared to its counterpart and POEMS syndrome. Careful inspection of clinical profiles and symptoms of patients presenting with neuropathy can help to discriminate those with underlying plasma cell disorders. The phenotype of neuropathy, platelet count and age at presentation seem to be the most useful indicators.

Monoclonal Gammopathy-Associated Peripheral Neuropathy: Diagnosis and Management

Monoclonal gammopathies comprise a spectrum of clonal plasma cell disorders that include monoclonal gammopathy of undetermined significance, multiple myeloma, and Waldenström macroglobulinemia. In this review, we outline the epidemiology, etiology, classification, diagnosis, and treatment of monoclonal gammopathy-associated peripheral neuropathy. Monoclonal gammopathy of undetermined significance is relatively common in the general population, with a prevalence of 3% to 4% among individuals older than age 50 years. Therefore, the presence of M protein in a patient with neuropathy does not automatically indicate a causal relationship. Monoclonal gammopathy-associated peripheral neuropathy is often a difficult diagnosis with limited treatment options. Studies addressing the optimal approach to diagnosis and management of this entity are limited. In addition to a review of the literature, we present a diagnostic approach to patients with monoclonal gammopathy-associated peripheral neuropathy and discuss available data and options for treatment.

Diagnosis and management of neuropathies associated with plasma cell dyscrasias

Neuropathies associated with plasma cell dyscrasias are a major cause of morbidity for patients managed by medical oncologists. Because of similarities in clinical presentation and on nerve conduction studies, identifying the underlying disease leading to a paraproteinemic neuropathy can often be difficult. In addition, the degree of neurologic deficit does not strictly correlate with the extent of abnormalities on common clinical laboratory testing. Fortunately, with increasing understanding into the biologic mechanisms of underlying hematologic diseases, additional biomarkers have recently been developed, thus improving our diagnostic capacity. Neuropathies associated with plasma cells dyscrasias are seen with Monoclonal gammopathy of undetermined significance (MGUS) particularly IgM subtype, followed by IgG and IgA MGUS, multiple myeloma, Waldenström's macroglobulinemia, amyloid, Castleman's disease, and POEMS syndrome. The mechanisms of neuronal injury associated with plasma cell dyscrasia vary based on underlying diagnosis and include malignant infiltration, immune-mediated antibody deposition, or local compression of nerve roots. The polyneuropathies are frequently demyelinating, although axonal and mixed neuropathies can also be seen. As demonstrated by the cases included in this review, patients frequently present with symmetric sensory disturbance, followed by progressive motor weakness. Unfortunately, because of the complexity of diagnostic testing, patients are frequently examined late, often after receiving several ineffective therapies. The aim of this case-based review is to provide clinicians with insight on how to properly recognize these atypical neuropathies and send the appropriate diagnostic work, increasing the likelihood of accurately classify the patient's underlying hematologic disorder.

Intravenous immunoglobulin in the treatment of neurologic disorders

Intravenous immunoglobulins (IVIGs) are often used in the treatment of autoimmune disorders and immunodeficiencies, and it has been estimated that neurologic indications can account for up to 43% of IVIG used in clinical practice. In neurologic clinical practice, IVIG is used for acute therapy of newly diagnosed autoimmune disorders or exacerbations of pre-existing conditions, or as long-term maintenance treatment for chronic disorders. IVIG exerts its effects on humoral and cell-based immunity through multiple pathways, without a single dominant mechanism. Clinical use of IVIG has been supported by guidelines from American Academy of Neurology and European Federation of Neurologic Societies. IVIG is generally recommended for the treatment of Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy in adults, multifocal motor neuropathy and myasthenia gravis, and should be considered as a treatment option for dermatomyositis in adults and Lambert-Eaton myasthenic syndrome. Additional potential indications include stiff person syndrome, multiple sclerosis during pregnancy or while breastfeeding, refractory autoimmune epilepsy, and paraneoplastic disorders. Clinical use of IVIG is mostly safe but few adverse effects may still occur with potentially severe complications, including aseptic meningitis and thromboembolism. In addition to intravenous route (IVIG), subcutaneous immunoglobulins have been used as an alternative treatment option, especially in patients with limited intravenous access. Treatment with IVIG is effective in various autoimmune diseases, but its broader use is constrained by limited supply. This review evaluates the use of immunoglobulins in treatment of neurologic diseases.

Paraproteinemic neuropathy: a practical review

The term paraproteinemic neuropathy describes a heterogeneous set of neuropathies characterized by the presence of homogeneous immunoglobulin in the serum. An abnormal clonal proliferation of B-lymphocytes or plasma cells, which may or may not occur in the context of a hematologic malignancy, produces the immunoglobulins in excess. If malignancy is identified, treatment should be targeted to the neoplasm. Most cases, however, occur as monoclonal gammopathy of undetermined significance. Few prospective, randomized, placebo-controlled trials are available to inform the management of paraproteinemic neuropathies. Clinical experience combined with data from smaller, uncontrolled studies provide a basis for recommendations, which depend on the specific clinical setting in which the paraprotein occurs. In this review, we provide a clinically practical approach to diagnosis and management of such patients.

Autoantibody-Mediated Sensory Polyneuropathy Associated with Indolent B-Cell Non-Hodgkin's Lymphoma: A Report of Two Cases

Background and Purpose

Abnormalities of the peripheral nervous system occur in 5% of patients with lymphoma. Polyneuropathy has not been described in patients with mantle-cell and marginal-zone B-cell lymphomas.

Case Report

Two elderly patients with indolent non-Hodgkin's lymphoma developed a progressive sensory polyneuropathy that was associated with serum autoantibodies directed against asialosyl/sialosyl gangliosides and myelin-associated glycoprotein/sulfated glucuronyl paragloboside, respectively, which are peripheral-nerve antigens. The oligoclonal pattern of these antibodies hinted at a lymphoma-induced immune dysregulation. The neuropathy stabilized clinically during treatment with intravenous immunoglobulin G. B-cell lymphoma was managed with a "watchful waiting" approach.

Conclusions

The concept of antigen-specific, immune-mediated neuropathy associated with slow-growing lymphoma of mature B-cells may be underrecognized. The principle of treating the illness underlying neuropathy may not be always indicated or necessary if risk-benefit and cost-benefit analyses are taken into account.

Autoimmune neuromuscular disorders

Autoimmune neuromuscular disorders affecting peripheral nerves, neuromuscular junction or muscle have a wide clinical spectrum with diverse pathogenetic mechanisms. Peripheral nervous system may be targeted in the context of complex immune reactions involving different cytokines, antigen-presenting cells, B cells and different types of T cells. Various immunomodulating and cytotoxic treatments block proliferation or activation of immune cells by different mechanisms attempting to control the response of the immune system and limit target organ injury. Most treatment protocols for autoimmune neuromuscular disorders are based on the use of corticosteroids, intravenous immunoglobulins and plasmapheresis, with cytotoxic agents mostly used as steroid-sparing medications. More recently, development of specific monoclonal antibodies targeting individual cell types allowed a different approach targeting specific immune pathways, but these new treatments are also associated with various adverse effects and their long-term efficacy is still unknown.

Diseases Involving Myelin

This chapter focuses on multiple sclerosis and the acquired and inherited peripheral neuropathies. The integrity of myelin sheaths is dependent upon the normal functioning of the myelin-forming oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS) as well as on the viability of the axons that they ensheath. Neuronal death inevitably leads to degeneration of axons and secondary degeneration of the myelin surrounding them. Failure of synthesis of normal myelin proteins or lipids is referred to as hypomyelination or dysmyelination. Primary demyelination involves the destruction of myelin with relative sparing of axons, whereas secondary demy­elination includes those disorders in which myelin is involved only after damage to neurons and axons occurs. The integrity of myelin sheaths is dependent upon the normal functioning of myelin-forming oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS) as well as on the viability of the axons that they ensheath.

Update on paraneoplastic neurologic disorders

When patients with cancer develop neurologic symptoms, common causes include metastasis, infections, coagulopathy, metabolic or nutritional disturbances, and neurotoxicity from treatments. A thorough clinical history, temporal association with cancer therapies, and results of ancillary tests usually reveal one of these mechanisms as the etiology. When no etiology is identified, the diagnosis considered is often that of a paraneoplastic neurologic disorder (PND). With the recognition that PNDs are more frequent than previously thought, the availability of diagnostic tests, and the fact that, for some PNDs, treatment helps, PNDs should no longer be considered diagnostic zebras, and when appropriate should be included in the differential diagnosis early in the evaluation.