PNMA2 forms immunogenic non-enveloped virus-like capsids associated with paraneoplastic neurological syndrome

The paraneoplastic Ma antigen (PNMA) proteins are associated with cancer-induced paraneoplastic syndromes that present with an autoimmune response and neurological symptoms. Why PNMA proteins are associated with this severe autoimmune disease is unclear. PNMA genes are predominantly expressed in the central nervous system and are ectopically expressed in some tumors. We show that PNMA2, which has been co-opted from a Ty3 retrotransposon, encodes a protein that is released from cells as non-enveloped virus-like capsids. Recombinant PNMA2 capsids injected into mice induce autoantibodies that preferentially bind external "spike" PNMA2 capsid epitopes, whereas a capsid-assembly-defective PNMA2 protein is not immunogenic. PNMA2 autoantibodies in cerebrospinal fluid of patients with anti-Ma2 paraneoplastic disease show similar preferential binding to spike capsid epitopes. PNMA2 capsid-injected mice develop learning and memory deficits. These observations suggest that PNMA2 capsids act as an extracellular antigen, capable of generating an autoimmune response that results in neurological deficits.

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.

Immunophenotypical characterization of paraneoplastic neurological syndrome patients: a multicentric study

Paraneoplastic neurological syndromes (PNS) are a group of rare and severe immune-mediated disorders that affect the nervous system in patients with cancer. The best way to diagnose a paraneoplastic neurological disorder is to identify anti-onconeural protein antibodies that are specifically associated with various cancers. The aim of this multicentric study was to clinically and immunologically characterize patients with PNS and study their association with cancer. Patients suspected to have PNS were enrolled from various clinical centres and were characterized immunologically. This study population consisted of 112 patients. Onset of PNS was mainly subacute (76 %). PNS patients had various neurological disorders and symptoms. PNS developed before the diagnosis of cancer in 28 definite PNS patients and in six suspected PNS patients. The most frequent autoantibodies detected in PNS patients were anti-Hu and anti-Yo. One definite PNS patient with cerebellar syndrome had anti-Tr antibody and seven patients had atypical antibodies. The literature associates these antibodies with various neurological disorders and cancers. Our observations confirm the important role of autoantibodies in PNS and their importance for the early diagnosis of cancer in PNS patients.

Neurological complications of pediatric cancer

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.

Significance of Autoantibodies in Autoimmune Encephalitis in Relation to Antigen Localization: An Outline of Frequently Reported Autoantibodies with a Non-Systematic Review

Autoantibodies related to central nervous system (CNS) diseases propel research on paraneoplastic neurological syndrome (PNS). This syndrome develops autoantibodies in combination with certain neurological syndromes and cancers, such as anti-HuD antibodies in encephalomyelitis with small cell lung cancer and anti-Yo antibodies in cerebellar degeneration with gynecological cancer. These autoantibodies have roles in the diagnosis of neurological diseases and early detection of cancers that are usually occult. Most of these autoantibodies have no pathogenic roles in neuronal dysfunction directly. Instead, antigen-specific cytotoxic T lymphocytes are thought to have direct roles in neuronal damage. The recent discoveries of autoantibodies against neuronal synaptic receptors/channels produced in patients with autoimmune encephalomyelitis have highlighted insights into our understanding of the variable neurological symptoms in this disease. It has also improved our understanding of intractable epilepsy, atypical psychosis, and some demyelinating diseases that are ameliorated with immune therapies. The production and motility of these antibodies through the blood-brain barrier into the CNS remains unknown. Most of these recently identified autoantibodies bind to neuronal and glial cell surface synaptic receptors, potentially altering the synaptic signaling process. The clinical features differ among pathologies based on antibody targets. The investigation of these antibodies provides a deeper understanding of the background of neurological symptoms in addition to novel insights into their basic neuroscience.

Autoimmune paraneoplastic syndromes associated to lung cancer: A systematic review of the literature Part 4: Neurological paraneoplastic syndromes, involving the peripheral nervous system and the neuromuscular junction and muscles

The development of new immune treatment in oncology and particularly for lung cancer may induce new complications, particularly activation or reactivation of auto-immune diseases. In this context, a systematic review on the auto-immune paraneoplastic syndromes that can complicate lung cancer appears useful. This article is the fourth of a series of five and deals mainly with neurological paraneoplastic syndromes involving the peripheral nervous system and the neuromuscular junction and muscles.

Immune-Mediated Neuropathies following Autologous Stem Cell Transplantation for Multiple Myeloma: Case Series and Review of the Literature

Neuropathy is a common finding in patients with multiple myeloma. Several different factors can cause neuropathy in these patients, such as the underlying disease itself, medications used for treatment, or immune-mediated processes. Immune-mediated neuropathies (IMN) consist of a heterogeneous spectrum of peripheral nerve disorders. Although IMN is associated with several hematological disorders, it remains a very rare complication of hematopoietic stem cell transplantation (HCT). We describe our experiences of 3 patients with multiple myeloma who experienced IMN following autologous HCT (auto-HCT). These 3 patients were felt to have IMN clearly attributable to auto-HCT because of a clear temporal association with auto-HCT and absence of any other obvious causative factor. The variety in their clinical presentations, diagnostic approach, and approaches to management are explained. The pathophysiology of how HCT may predispose to IMN remains poorly understood. Our report helps highlight several potential causes of this phenomenon, such as a paraneoplastic syndrome, immune reconstitution syndrome, or drug toxicity. We emphasize that a comprehensive approach is needed to address this rare entity, and that there should be a low threshold to initiate immune-specific therapy, such as plasmapheresis, if symptoms do not resolve spontaneously.

A coin-like peripheral small cell lung carcinoma associated with acute paraneoplastic axonal Guillain-Barre-like syndrome

A 65-year-old previously healthy male heavy smoker was hospitalized with a 2-week history of progressive muscle weakness in the lower and upper extremities. After 10 days of hospitalization, urinary sphincter incompetence and fecal incontinence were added and tetraparesis was established. The computer-tomography scan examination revealed a massive right hydrothorax and multifocal solid acinar structures with peripheral localization in the left lung, which suggested pulmonary cancer. Bone marrow metastases were also suspected. Based on the examination results, the final diagnosis was acute paraneoplastic axonal Guillain-Barre-like syndrome. The patient died 3 weeks after hospitalization. At autopsy, bronchopneumonia and a right hydrothorax were confirmed. Several 4 to 5-mm-sized round peripherally located white nodules were identified in the left lung, without any central tumor mass. Under microscope, a coin-shaped peripheral/subpleural small cell carcinoma was diagnosed, with generalized bone metastases. A huge thrombus in the abdominal aorta and acute pancreatitis was also seen at autopsy. This case highlights the difficulty of diagnosis of lung carcinomas and the necessity of a complex differential diagnosis of severe progressive ascending neuropathies. This is the 6th reported case of small cell lung cancer-associated acute Guillain-Barre-like syndrome and the first report about an association with a coin-like peripheral pattern.

Paraneoplastic neurological disorders in children with benign ovarian tumors

AIM

Paraneoplastic neurological diseases (PND) are rare, but potentially treatable disorders. Paraneoplastic encephalitis is rapidly emerging as an important but likely under-recognized condition in children. The aim of this study was to assess the prevalence and spectrum of PND in children with benign ovary tumor and the long-term outcome.

PATIENTS AND METHODS

We retrospectively reviewed the charts of all female patients below 18years of age diagnosed with a benign ovarian tumor proven by pathology between January 1993 and December 2010. All the clinical symptoms developed within 5years of tumor diagnosis and the related investigations were recorded.

RESULTS

There were total 133 children and adolescents with benign ovarian tumors, mostly mature teratoma. Six patients (4.5%) had neuropsychiatric manifestations and all but one were beyond age 10years. The most common neuropsychiatric presentations were depression or low mood (84%), headache (50%), mutism (50%), hypoventilation (50%), seizures (30%), hallucination (30%), vomiting and hypersalivation (30%). Three patients (2.2%) had serious PND including acute disseminated encephalomyelitis in 1 and anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis in 2. Although all of three improved after tumor removal, one without immunotherapy had neurological sequelae and prolonged ICU stay.

CONCLUSION

The prevalence of PND in benign ovary tumor is not so uncommon in children. It is important to survey ovary tumors in female adolescents with subacute presentation of multiple-level involvement of neuraxis where no clear alternate diagnosis is possible. Treatment of serious PND associated with ovary tumors should include immunotherapy in addition to tumor removal.

Paraneoplastic disorders of the central and peripheral nervous systems

Paraneoplatic neurologic syndromes (PNS) have been seminally defined as acute or subacute neurological syndromes resulting from nervous system dysfunction that is remote from the site of a malignant neoplasm or its metastases. However, in respect to our current understanding of their pathogenesis we may redefine these disorders as cancer-related dysimmune neurologic syndromes. We first deal with the epidemiology and the pathogenesis of PNS, then the different classic PNS are reviewed with clinical features according to the associated onconeuronal antibodies. Finally, therapeutic approaches are discussed.

[Paraneoplastic neurological syndrome in 12 children]

OBJECTIVE

To investigate the basic clinical characteristics of paraneoplastic neurological syndrome (PNS) in children.

METHOD

To retrospectively analyze the clinical data of 12 PNS children who were hospitalized in neurology department in Beijing Children's Hospital from 2010 to 2011. Some patients were followed up after surgery.

RESULT

In 12 patients with PNS, 11 were male and 1 was female. The mean onset age were (30.5 ± 15.3) months. The mean duration from neurological symptom onset to finding out of tumor was (112.7 ± 154.4) days. The onset of the disease in 2 patients was acute, in 3 was subacute and in the other 7 was chronic (2 of 7 had 2 to 3 relapses). Of 12 patients, 11 had symptoms of ataxia (3 patients also had opsoclonus and myoclonus, OMS), 1 had weakness of limbs at onset and then had ataxia. Nine of 12 patients had surgery, and pathologic diagnosis was neuroblastoma and ganglioneuroma. Six patients were followed-up for 8 to 21 months. One patient had a little improvement and 5 almost recovered.

CONCLUSION

The PNS children can have neurological symptoms only at the onset and there were no particular evidence of tumor. It is prone to misdiagnosis. The prognosis of PNS in children was poor.

Anti-Hu-associated paraneoplastic encephalomyelitis with esophageal small cell carcinoma

A 63-year-old woman had anti-Hu-associated paraneoplastic encephalomyelitis (anti-Hu syndrome) caused by esophageal small cell carcinoma (SCC). The patient developed bilateral limbic encephalitis, followed by myelitis, brain stem encephalitis, and autonomic failure. Extensive examination demonstrated SCC of the abdominal lymph nodes that was retrospectively diagnosed as metastasis of esophageal SCC on autopsy. The neuropathological findings were characterized by widespread neuronal loss and gliosis in the central nervous system, as well as patchy loss of myelin and axons in the spinal nerve roots with perivascular lymphocytic infiltration. This is the first detailed clinical and neuropathological report of anti-Hu syndrome caused by esophageal SCC.

Relationship between neural alteration and perineural invasion in pancreatic cancer patients with hyperglycemia

BACKGROUND

Patients with higher levels of fasting serum glucose have higher death rates from pancreatic cancer compared to patients with lower levels of fasting serum glucose. However, the reasons have not been studied. The goal of the current study was to examine the neural alterations in pancreatic cancer patients with hyperglycemia and to identify the relationship between the neural alterations and perineural invasion.

METHODOLOGY/PRINCIPAL FINDINGS

The clinical and pathological features of 61 formalin-fixed pancreatic cancer specimens and 10 normal pancreases as controls were analyzed. Furthermore, the expression of Protein Gene Product 9.5 (PGP9.5), Myelin P0 protein (MPP), NGF, TrkA, and p75 were examined by immunohistochemistry. The median number of nerves, the median area of neural tissue, and the median nerve diameter per 10 mm(2) were larger in the hyperglycemia group than those in the euglycemia group (p = 0.007, p = 0.009, and p = 0.004, respectively). The integrated optical density (IOD) of MPP staining was lower in the hyperglycemia group than those in the euglycemia group (p = 0.019), while the expression levels of NGF and p75 were higher in the hyperglycemia group than those in the euglycemia group (p = 0.002, and p = 0.026, respectively). The nerve bundle invasion of pancreatic cancer was more frequent in the hyperglycemia group than in the euglycemia group (p = 0.000).

CONCLUSIONS/SIGNIFICANCE

Nerve damage and regeneration occur simultaneously in the tumor microenvironment of pancreatic cancer patients with hyperglycemia; the simultaneous occurrence may aggravate the process of perineural invasion. The abnormal expression of NGF and p75 may also be involved in this process and subsequently lead to a lower rate of curative surgery.

Antibodies to the GABA(B) receptor in limbic encephalitis with seizures: case series and characterisation of the antigen

BACKGROUND

Some encephalitides or seizure disorders once thought idiopathic now seem to be immune mediated. We aimed to describe the clinical features of one such disorder and to identify the autoantigen involved.

METHODS

15 patients who were suspected to have paraneoplastic or immune-mediated limbic encephalitis were clinically assessed. Confocal microscopy, immunoprecipitation, and mass spectrometry were used to characterise the autoantigen. An assay of HEK293 cells transfected with rodent GABA(B1) or GABA(B2) receptor subunits was used as a serological test. 91 patients with encephalitis suspected to be paraneoplastic or immune mediated and 13 individuals with syndromes associated with antibodies to glutamic acid decarboxylase 65 were used as controls.

FINDINGS

All patients presented with early or prominent seizures; other symptoms, MRI, and electroencephalography findings were consistent with predominant limbic dysfunction. All patients had antibodies (mainly IgG1) against a neuronal cell-surface antigen; in three patients antibodies were detected only in CSF. Immunoprecipitation and mass spectrometry showed that the antibodies recognise the B1 subunit of the GABA(B) receptor, an inhibitory receptor that has been associated with seizures and memory dysfunction when disrupted. Confocal microscopy showed colocalisation of the antibody with GABA(B) receptors. Seven of 15 patients had tumours, five of which were small-cell lung cancer, and seven patients had non-neuronal autoantibodies. Although nine of ten patients who received immunotherapy and cancer treatment (when a tumour was found) showed neurological improvement, none of the four patients who were not similarly treated improved (p=0.005). Low levels of GABA(B1) receptor antibodies were identified in two of 104 controls (p<0.0001).

INTERPRETATION

GABA(B) receptor autoimmune encephalitis is a potentially treatable disorder characterised by seizures and, in some patients, associated with small-cell lung cancer and with other autoantibodies.

FUNDING

National Institutes of Health.

Therapeutic strategies for catatonia in paraneoplastic encephalitis

This report is about a 40-year-old man suffering from fluctuating catatonia as main symptom of long-lasting paraneoplastic encephalitis caused by a testicular neoplasm. With recurrence of a neoplasm initially diagnosed as seminoma after a 7-year symptom-free interval the patient suddenly developed various neurological and psychopathological symptoms including seizures, autonomic dysregulation, continuous anterograde short-term amnesia and predominantly a long-lasting complex catatonic syndrome with on-off phenomena. Repeated MRI scans of the brain showed no pathology; brain FDG-PET scans indicated a hypometabolism of the frontal cortex and the left temporal lobe. Eventually a paraneoplastic encephalitis was diagnosed. Repeated resections of tumour recurrences and plasmapheresis moderately alleviated catatonic symptoms. Haloperidol and lorazepam effectively relieved catatonic symptoms in contrast to various atypical antipsychotic drugs and diazepam. A series of 12 electroconvulsive treatments (ECT) temporarily improved residual catatonic symptoms such as catalepsy, stupor and mutism. Further neoplasm recurrences, however, reinforced catatonia until the tumour was successfully treated and the patient fully recovered. This case report illustrates the potential but also the limitations of various therapeutic approaches in organic catatonia due to paraneoplastic encephalitis.

[Classic paraneoplastic syndromes: diagnostic and treatment approach]

INTRODUCTION

Paraneoplastic neurological syndromes are important complications of cancer that are usually immune mediated. According to the clinical and immunological features, two groups of disorders can be considered. One group includes disorders mediated by antibodies against cell surface neuronal antigens; these syndromes often respond to treatment and have a favorable outcome. The other group includes disorders associated with antibodies against intracellular antigens; these syndromes are likely mediated by T-cell mechanisms, respond poorly to treatment, and have a less favorable outcome.

METHODS

Clinical and immunological analysis, and follow-up of four patients with classical paraneoplastic syndromes.

RESULTS

Three patients had serum and CSF antibodies to intracellular antigens and one had no detectable antibodies. Despite the severity of the symptoms, prompt detection and treatment of the tumor and immunotherapy modified the course of the disease and resulted in substantial improvement of the quality of life.

CONCLUSIONS

Prompt diagnosis of the tumor and immunotherapy may positively impact the clinical outcome and improve the quality of life of patients with paraneoplastic syndromes believed to have a poor prognosis.

Autoantibodies against glial antigens in paraneoplastic neurological diseases

Paraneoplastic neurological syndromes are clinically heterogeneous manifestations of cancer, but are not caused by the tumor or its metastases. Because autoantibodies reacting with tumor and nervous system tissue have been described, an autoimmune pathogenesis is suspected. Most autoantibodies are directed against neuronal proteins. Here, we describe the impact of antiglial autoantibodies in paraneoplastic neurological syndromes. Anti-CRMP5 and antiglial nuclear antibody both can be associated with different paraneoplastic neurological syndromes and tumors.

Intravascular large B-cell lymphoma presenting with neurological syndromes: clinicopathologic study

Intravascular lymphoma or intravascular lymphomatosis (IVL) is an uncommon extranodal lymphoma, which gives rise to exclusively intravascular tumor growth. In 1/3 of the reported cases the disease debuts with involvement of the nervous system, which is particularly susceptible. Over the clinical course of the disease, 2/3 of the patients will present neurological symptoms. Owing to its characteristic growth pattern, IVL can give rise to very different central or peripheral nervous system neurological syndromes. Not infrequently a single patient will present more than one neurological syndrome. Moreover, the specificity of the neurological tests is low. All these factors explain the difficulties involved in diagnosing this entity and the fact that in most cases the diagnosis is established on autopsy study. This article presents the clinical, biological, radiological and post-mortem neuropathological findings in an immunocompetent patient with IVL. The onset was a cauda equina syndrome and showed multiple and varied neurological manifestations during the course of the disease, which progressed in the months before death. Spinal cord biopsy performed in life did not provide diagnostic findings because the vessels showed no neoplastic involvement. Immunohistochemical findings demonstrated large B-cell lymphoma. A review of the neurological features described in previously published cases of IVL is provided.

Diffusion-Tensor Imaging at 3 T

OBJECTIVE

Fractional anisotropy (FA) is a powerful measure to study the integrity of the cerebral white matter in vivo. However, because clinical FA assessments are frequently based on single slice evaluations, intra- and interindividual comparisons are highly dependent on image alignment. We attempted to develop an observer-independent, fully automated technique for quantitative FA assessment.

MATERIALS AND METHODS

We employed whole brain diffusion tensor imaging at 3 T with an echo planar imaging sequence (isotropic spatial resolution 1.8 mm) on 4 patients (2x Alzheimer disease, 1x microangiopathy, 1x paraneoplastic disease) and 2 normal control groups (group "young," age 19-32 years; group "old," age 59-69 years). The images were spatially normalized to the standard brain template of the Montreal Neurologic Institute. We introduced a fractional anisotropy index (FAI) as a single measure for the mean tissue anisotropy in certain brain regions of interest. The regions of interest were defined by masks in relation to the Montreal Neurologic Institute coordinate space. We varied the spatial extent of the masks. Confidence intervals of the FAIs for both control groups were calculated.

RESULTS

We found the resulting FAIs to be highly robust against considerable mask variations (product-moment correlation: r > 0.97). The FAIs of the 4 patients presented with neurologic conditions associated with white matter alterations significantly fell outside the confidence intervals for normal FA.

CONCLUSION

FAIs based on mean fractional anisotropy values obtained from isotropic whole-head high-field diffusion tensor imaging by fully automated algorithms represent a robust and observer-independent measure for the comparative assessment of white matter integrity, ideally suited for further statistical treatments.

Multiple hemorrhagic strokes from DIC associated with occult large cell carcinoma

BACKGROUND AND PURPOSE

Multiple hemorrhagic strokes are a rare presentation of paraneoplastic disseminated intravascular coagulation (DIC). We present a case of DIC occurring in a patient with occult large cell carcinoma.

SUMMARY OF CASE

A 77-year old Asian-American man presented with 1 month of vision disturbance followed by acute onset of left hemiparesis and encephalopathy. He was found to have three strokes of varying ages, and was placed on aspirin and clopidogrel. He returned 4 days later with hemorrhagic conversion of the strokes and laboratory abnormalities suggestive of DIC. Over the hospital course, he suffered recurrent ischemic strokes and intracerebral hemorrhages despite management of his coagulopathy. On autopsy, an occult large cell carcinoma was found in the hilar lymph nodes, as well as multiple intravascular thrombi.

CONCLUSIONS

Recurrent hemorrhagic strokes associated with DIC may be the initial presentation of occult malignancy. Although adenocarcinoma is classically associated with paraneoplastic DIC, this case demonstrates that large cell carcinoma may also be implicated.

Isolated frontal disequilibrium as presenting form of anti-Hu paraneoplastic encephalomyelitis

Anti-Hu encephalomyelitis is one of the most frequent paraneoplastic syndromes, classically presenting with diffuse neurological involvement. We report a 69-year-old man presenting with a three-month isolated, progressive gait disorder with normal neurological examination, except for loss of balance and gait failure reminding frontal disequilibrium, only accompanied by a very mild rigidity of his right foot. MRI of the brain showed hyperintensities in both amygdale and left putamen. EMG study showed no abnormal continuous spontaneous fiber activity. Because of fast progression and MRI findings, anti-Hu antibodies were tested, resulting positive. Mediastinal biopsy of two adenopathies detected by body-PET, confirmed an oat-cell carcinoma. The patient received oral steroids and oncological therapy. One year later, the tumor is in remission. His gait and abnormal posture of right leg are normal. Only mild residual hyperintensities persist on follow-up MRI. A paraneoplastic syndrome should be considered in the differential diagnosis of subacute, fast progressive gait disorders.

Paraneoplastic neurologic syndromes

Paraneoplastic neurologic disorders (PND) are remote medical complications of cancer that cannot be attributed to direct effects of the neoplasm or its metastases. PND are uncommon, disabling syndromes that have been recognized for more than 50 years. Despite their rarity, these diseases are the subject of intensive research and clinical fascination. This review highlights notable recent publications related to PND. In recent years, the broad clinical spectrum of PND has become even more apparent. PND can affect any part of the central or peripheral nervous system and often affect multiple areas simultaneously. These disorders are often associated with neuron-specific autoantibodies in the serum and cerebrospinal fluid. In clinical practice, detection of these antibodies is crucial for the diagnosis because the neurologic symptoms usually precede the diagnosis of cancer. Recent publications have described new antibody specificities associated with PND and expand our ability to identify patients serologically. Once diagnosed, detection of cancer can be difficult, but the use of positron emission tomography has been shown to be a useful supplement to standard imaging procedures. PND are thought to be autoimmune disorders precipitated by the immune response to cancer. Observations and laboratory studies in PND patients have shown that activation of cytotoxic T cells is an important component of the disease. These studies not only shed light on the pathogenesis of PND and the mechanisms of effective antitumor immunity but may eventually lead to improved treatment.

Peripheral nervous system involvement in patients with cancer

Involvement of the peripheral nervous system (PNS) is common in patients with cancer and any part, including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions, can be affected. Different mechanisms can initiate damage associated with cancer-related PNS disorders. These include tumour infiltration, toxicity of treatments, metabolic and nutritional perturbations, cachexia, virus infections, and paraneoplastic neurological syndromes. The type of cancer, lymphoma, or solid tumour is a further determinant of a PNS disorder. In this Review we discuss the different causes and mechanisms of disorders of the PNS in patients with cancer and we will focus on their assessment and diagnosis.

[Multiple paraneoplastic syndromes occurring in the same patient: clinical, imaging and neuro-pathological documentation]

Paraneoplastic neurological syndromes (PNS) are remote effects of cancer, which are not caused by invasion of the tumour or its metastasis, but presumably immunologic mediated. They developed in less than 1% of patients with systemic cancers, most Limbic encephalitis (LE) is the most common clinical paraneoplastic syndrome attainting the CNS (Central Nervous System), and it is characterized by involvement of hippocampus and amygdala; LE is also the only one with clearly defined imaging features. We report a 64 year old man, former smoker, which presented multiple paraneoplastic syndromes, namely LE, opsoclonus-myoclonus, subacute cerebellar degeneration, brainstem encephalitis, sensory-motor neuropathy and inappropriate antidiuretic hormone secretion syndrome (SIADH); these syndromes were identifiable in the clinical and imaging examination, confirmed by the neuro-pathological study. Magnetic Resonance Imaging disclosed on T2 weighted images bilateral hyperintensity within medial temporal lobes, hypothalamus, thalamus, brain stem, upper and medium cerebellar peduncles and upper cervical spinal cord. The underlying tumour was not found in imaging studies or in the autopsy examination. A mediastinal adenopathy depicted a metastasis from low differentiated neoplasm cells, with some signs of neuroendocrine differentiation. With this case we provide a comprehensive illustration of the PNS, from a clinical, imaging and pathological point of view. This report also emphasises the importance of a diagnosis based on early clinical and imaging findings, given that, in most cases the cancer is not apparent.

Spontaneous remission of small cell lung cancer: A case report and review in the literature

Spontaneous remission (SR) of cancer, especially of lung tumor, is a rare biological event. Only seven cases in which small cell lung cancer (SCLC) regressed spontaneously had been previously reported. We report here a rare case of complete SR of SCLC in an 86-year-old man. Paraneoplastic sensory neuronopathy (PSN) is a rare syndrome, which is associated with malignancy such as SCLC and starts with dysesthetic pain and numbness in the distal extremities, then spreading all four limbs and trunk causing severe sensory ataxia. In the previous reports, SR of SCLC is suggested to result from surgical trauma or PSN, which may be able to enhance anti-tumoral immunity. Our report is the case of SR of SCLC, without any therapies nor any invasive examinations. Although the reason of SR of SCLC in the present case is unknown, PSN could be one of the diagnosis by exclusion.

[Paraneoplastic encephalitis]

Paraneoplastic neurodegenerative diseases are defined as damage to central and peripheral nervous tissue related to a malignancy, in the absence of metastases. If they represent first disease manifestation, the diagnosis can pose a real problem. A case of 59-year-old woman is described, who suffered during her last nine months of life from meningoencephalitis, with cranial nerves pareses and progressive quadruparalysis. The CSF exhibited a temporary inflammatory response with slow improvement, whereas the clinical status progressed continually toward terminal bronchopneumonia. An extensive infectious agent search was negative. Though the result of the autoantibody panel available (anti Yo, Hu, Ri) was negative, the paraneoplastic degeneration remained a part of the differential diagnosis. Post-mortem examination revealed residual brain stem meningoencephalitis and advanced cerebellar loss of Purkinje cells, in the presence of a neuroendocrine small cell lung carcinoma in the right lower lobe. The carcinoma only manifested intravitally, with paratracheal lymphadenomegaly on imaging. Rapid progress in the diagnostics of autoimmune neurodegeneration with the increasing spectrum of autoantibody detection tools has recently increased the possibilities of revealing clinically silent, primary manifesting neurodegeneration. In the future, it may also represent a target for therapeutic intervention.

Paraneoplastic neurodegeneration in a murine host following progressive growth of a spontaneous T-Cell lymphoma: role of proinflammatory internal responses

OBJECTIVE(S)

In the present study, the mechanism of paraneoplastic neurodegeneration associated with progressive in vivo growth of a T-cell lymphoma of spontaneous origin has been investigated.

METHODS

Histologically, the brain was investigated by hematoxylin-eosin staining of brain sections. Western blotting was performed to detect the expression of cytokines and other proteins. Macrophage-derived interleukin-1 (IL-1) and tumor necrosis factor (TNF) was estimated by immunoassays. Induction of apoptosis in brain and tumor cells was determined by percent specific DNA fragmentation.

RESULTS

Tumor growth was associated with the development of multiple lesions in various regions of the brain along with alterations in the structure and alignment of Purkinje cells, and an increase in the water content in the brain. Brain extract and serum of tumor-bearing mice showed higher levels of proinflammatory cytokines. Induction of apoptosis is suggested to be the cause underlying the loss of cellularity of tumor-bearing hosts in the brain owing to an augmentation in the induction of the caspase-dependent pathway of programmed cell death. Further, the study presents investigations to show the role of nitric oxide and proinflammatory cytokines IL-1, TNF, interferon-gamma and alkaline phosphatase in the manifestation of paraneoplastic neurodegeneration.

CONCLUSIONS

Growth of a T-cell lymphoma is associated with the manifestation of neurodegeneration caused by soluble proinflammatory factors of tumor and/or host origin.

Paraneoplastic limbic encephalitis presenting as acute viral encephalitis

OBJECTIVE

To describe a case of limbic encephalitis which initially presented as viral limbic encephalitis and during the clinical evaluation a renal carcinoma was diagnosed.

CASE REPORT

Patient with history of peripheral paresis of right facial nerve, 1 month after symptoms appearance and treatment, developed fever, vomiting, grand mal seizure, decreased level of consciousness, confusion, hallucinations and agitation. The patient initially presented a clinical picture of viral LE. which confirmed by CSF. MRI brain showed areas with pathological intensity signal in the region of limbic system unilateral. During the clinical evaluation a renal carcinoma was discovered and a nephrectomy has been performed.

CONCLUSIONS

Although PLE typically presents as a chronic or subacute disease, it may be fulminant and clinically indistinguishable from an acute HSVE. This association pose the problem of a possible relation between this two syndromes and the correct diagnosis is very important, because there are effective treatments.

Anti-glial nuclear antibody: marker of lung cancer-related paraneoplastic neurological syndromes

We describe a new antibody, called anti-glial nuclear antibody (AGNA), in patients with paraneoplastic neurological syndromes (PNS) and small-cell lung carcinoma (SCLC). AGNA was initially identified in 24 sera of our archives by immunohistochemistry on rat cerebellum. AGNA positive sera showed a characteristic nuclear staining of the Bergmann glia in the Purkinje cell layer. Immunoblots and probing a cerebellar expression library with AGNA sera did not identify the antigen. Twenty of the 24 patients with AGNA had PNS and all but two had lung cancer. AGNA was identified in 13/113 (11.5%) patients with SCLC compared with 0/122 with other types of cancer (p<0.0001). The frequency of AGNA was not higher than expected for the presence of SCLC in the different PNS subtypes except in LEMS (p=0.0002). AGNA was present in 13/30 (43%) of LEMS patients with SCLC, compared with 0/19 of LEMS patients without cancer (p=0.0006). We conclude that the recognition of AGNA is helpful since this antibody is found in PNS associated with SCLC, particularly LEMS, in which other onconeural antibodies are absent.

[An autopsied case of paraneoplastic neurologic syndrome (limbic encephalitis, cerebellar degeneration, and pseudohypertrophy in the inferior olivary nuclei) associated with T cell lymphoma]

We describe a patient with paraneoplastic neurologic syndrome confirmed on postmortem examination. This 42-year-old man was admitted due to general fatigue, emaciation and acute-onset disorientation. Neurological examination revealed disorientation, moderate cognitive impairment, cerebellar ataxia, bilateral limitations and nystagmus in all directions during external ocular movement, swallowing disorder, bilateral Babinski sign, sensory disturbance in the distal parts of all extremities, and Romberg's sign. T-cell lymphoma was diagnosed following biopsy of the cervical lymph node. Neurological condition improved slightly after chemotherapy, but subsequently deteriorated. At about 6 years after the disease onset, brain magnetic resonance imaging (MRI) revealed atrophy of bilateral hippocampi and the upper vermis of the cerebellum. The patient died of pneumonia after a clinical course of about 6 years and 6 months. Pathologically, neuronal loss, reactive gliosis and perivascular lymphocytic infiltration were observed in the hippocampi, cerebellum, and inferior olivary nuclei. Lymphocytes around the vessels were positive for LCA and UCHL-1, but negative for CD8 and L26, and thus were considered to be T cells. No lymphoma cell was observed in the central nervous system or lymphatic organs. Based on the pathological findings, paraneoplastic neurologic syndrome (limbic encephalitis, cerebellar degeneration and olivary pseudohypertrophy) associated with T-cell type malignant lymphoma was diagnosed. Only three other cases of paraneoplastic neurologic syndrome associated with T-cell lymphoma have been reported. In those cases, death occurred due to the deterioration of malignant lymphoma, whereas the present patient died about 6 years after the remission of malignant lymphoma. Prognosis may thus depend on the course of the malignant lymphoma. In the present patient, neurological symptoms deteriorated after remission of malignant lymphoma, and no pathological lesion were found in the lymphatic organs. Lesions in the central nervous system in paraneoplastic neurological syndromes may follow a course independent of the original malignant disease.

Surface-binding autoantibodies to cerebellar neurons in opsoclonus syndrome

Childhood opsoclonus-myoclonus syndrome can occur with or without associated neuroblastoma. An autoimmune pathogenesis has been discussed for both forms. We show here that the majority of children with opsoclonus-myoclonus syndrome (10/14) have autoantibodies binding to the surface of isolated rat cerebellar granular neurons. In some patients, these antibodies are masked by IgG binding to ubiquitous surface antigens, which could be removed by preincubation with the nonneuronal control cell line HEK 293. A newly introduced competitive binding assay showed that the surface binding is directed against the same autoantigen in different patients. Therefore, we hypothesize that opsoclonus-myoclonus syndrome may be the result of an autoimmune process against a neuronal surface protein.

Paraneoplastic Neurological Antibodies: A Laboratory Experience

Antineuronal antibodies are associated with rare paraneoplastic neurological syndromes, and their identification alerts clinicians to examine for the presence of a tumor. Presented here is laboratory experience (prevalence, difficulties, and procedures) and several interesting but inconclusive results. A total of 1045 samples were screened over a 2-year period; 91 showed a degree of binding of antibodies to the cerebellum, and 22 of these 91 were confirmed, by Western blot, to have specific antineuronal antibodies. Thirteen of 22 were Hu-positive, and 6 of these also had antinuclear antibodies. Six were Yo-positive, 2 had anti-Ma antibodies, and 1 was Tr-positive. An additional 27 of 91 patients had cerebellar antibodies giving recognized staining patterns (Hu, Yo, and Ma). However, Western blot did not confirm these specificities, and hence they were reported as atypical. Six of 27 of these patients had neoplasms; 3 of the 6 gave nucleolar patterns (not Ma). Two appeared similar to Yo, and 1 similar to Hu. Antineuronal antibodies are rare, and in the absence of a specific etiology patients should be examined further for the possible presence of an underlying tumor. Methodical classification of the antibodies must be conducted to avoid incorrect reporting. Further criteria on the typing/reporting of atypical results may aid diagnosis of paraneoplastic neurological syndromes.

Paraneoplastic encephalomyelitis/sensory motor peripheral neuropathy - an autopsy case study

Paraneoplastic neurological anti-Hu syndrome is one of the most frequent remote effects of cancer and usually manifests as encephalomyelitis combined with peripheral neuropathy. Subacute sensory neuronopathy, which results from the inflammatory destruction of sensory neurone cell bodies in the dorsal root ganglia, is thought to be the principal presentation of peripheral neuropathy. In addition to sensory involvement, evidence of motor nerve involvement is frequently found. The mechanisms of motor involvement remain largely unclear and there have been only a limited number of pathological studies. We present an autopsy case study of anti-Hu paraneoplastic encephalomyelitis/sensory-motor neuropathy, which confirms an inflammatory paraneoplastic destruction of sensory neuron cell bodies in the dorsal root ganglia and lower motor neurons in the spinal cord, as a cause of clinically rapidly progressive peripheral sensory-motor neuropathy.

A follow up study of patients with paraneoplastic neurological disease in the United Kingdom

OBJECTIVES

To examine the range of clinical phenotypes, tumour associations, relevant investigations, response to therapy and outcome in a large series of non-selected patients with paraneoplastic neurological disease (PND) affecting the central nervous system (CNS) in the United Kingdom.

METHODS

Data were obtained on patients either through direct referral or through the British Neurological Surveillance Unit (BNSU) from February 2000 to January 2001. Physicians were asked to supply information about age and sex of patients, presenting neurological syndromes, the basis of the diagnosis of PND, any associated malignancy, and treatment. Case notes were reviewed and follow up data obtained where possible one year after notification.

RESULTS

A total of 63 patients (48 females, 15 males) were identified, 48 through the BNSU and 15 through direct referral. Of these 52 were diagnosed as having definite PND, 10 probable PND, and 1 possible PND. The median age of onset of PND was 66 years (range 30-80 years) and only 7 patients (11%) were less than 50 years at presentation. In 53 patients (84%) the PND preceded the diagnosis of cancer. Paraneoplastic sensory neuronopathy, paraneoplastic encephalomyelitis, and paraneoplastic cerebellar degeneration (PCD) were the most common syndromes reported. The benefit of magnetic resonance imaging in the diagnosis of the disease was limited, while fluorodeoxyglucose positron emission tomography was shown to be useful for the detection of an occult malignancy in 10 out of 14 patients. Antineuronal antibodies were positive in 44/57 (77%) of cases. The following tumours were diagnosed: small cell lung cancer (30%), breast cancer (14%), ovarian cancer (8%), non-small cell lung cancer (8%), Hodgkin's lymphoma (6%), other (16%). With the exception of PCD associated with mesothelioma all other tumours diagnosed in these patients had been previously documented as being associated with PND. Only treatment of the tumour was found to be associated with a stable or improved neurological outcome at last follow up (Fisher's exact test = 4.7, p<0.03). Median survival time was 43 months (95% CI 28 to 57) from onset of neurological disease as calculated using the Kaplan-Meier survival analysis.

CONCLUSIONS

PND has a striking female preponderance usually affecting patients in their sixth decade and above. The median survival in our study was 43 months. The majority of patients with PND are not known to have cancer at the time of diagnosis. Our study confirms the importance of diagnosing and treating the underlying tumour.

FDG-PET improves tumour detection in patients with paraneoplastic neurological syndromes

To determine the usefulness of [18F]fluorodeoxyglucose (FDG) whole body FDG-PET in the diagnosis of tumours in patients with paraneoplastic neurological syndromes (PNS), we prospectively studied 20 patients with paraneoplastic antibodies in whom conventional imaging gave negative or inconclusive results for the presence of tumour. All 20 patients had neurological manifestations compatible with PNS and well-characterized paraneoplastic antibodies (12 anti-Hu, one anti-Hu and anti-CV2, one anti-CV2, four anti-Yo, one anti-Ri and one anti-amphiphysin). The mean delay between the onset of neurological symptoms and FDG-PET was 10 months (range 1-54). In these 20 patients, abnormal uptake was demonstrated in 18 patients, with some patients having abnormal signal in several areas. We observed abnormal uptake in the mediastinum (13 cases), lung (two cases), breast (two cases), parotid gland (one case), or the cervical, supraclavicular or axillary lymph nodes (seven cases). Following FDG-PET, the histological diagnosis of the tumour was made in 14 patients (small cell lung carcinoma in eight cases, breast adenocarcinoma in two, lung adenocarcinoma in two, axillary metastasis of ovary carcinoma in one, and malignant thymoma in one). Two other patients with abnormal FDG uptake showed radiological evidence of lung cancer, but a histological diagnosis could not be obtained. In two other patients, initial FDG-PET showed abnormal FDG uptake that was not confirmed a few months later by repeat FDG-PET. In the two patients with negative FDG-PET, peritoneal carcinomatosis was diagnosed in one and no tumour was found in the other. In our series, the sensitivity of FDG-PET for tumour detection was >83% demonstrating a clear role of this technique in the management of patients with PNS. However, in our series, the specificity of FDG uptake was only 25% due to unexplained abnormal FDG uptake in three patients and in abnormal FDG uptake due to a benign tumour in one patient. Over the study period, we saw 73 other patients with PNS and paraneoplastic antibodies. A tumour was demonstrated in 71 out of 73 by conventional techniques. Since false-positive and false-negative results are possible with FDG-PET and in most patients with PNS, the tumour is demonstrated by conventional techniques, we believe that FDG-PET should be reserved, at the moment, for patients with well-defined PNS antibodies when conventional imaging fails to identify a tumour or when lesions are difficult to biopsy.

Ataxia and secretory diarrhea: two unusual paraneoplastic syndromes occurring concurrently in the same patient with ganglioneuroblastoma

The presence of rare paraneoplastic syndromes, the opsoclonus-myoclonus-ataxia syndrome (OMA), presumably caused by antineuronal antibody production, and diarrhea, caused by vasoactive intestinal peptide (VIP) secreted by neuroblastoma, may strongly signal the presence of neuroblastoma. The authors describe a child who presented with both syndromes concurrently; this has never been described previously in the same patient. However, diagnosis of neuroblastoma was delayed by a workup focused on the prolonged diarrhea rather than the ataxia. The diarrhea resolved after tumor resection, whereas OMA required further therapy. Increased awareness of VIP-secretory diarrhea, especially in an ataxic child, might contribute to an earlier diagnosis of neuroblastoma.

ANNA-2: an antibody associated with paraneoplastic opsoclonus in a patient with large-cell carcinoma of the lung with neuroendocrine features--correlation of clinical improvement with tumor response

This report describes a case of large-cell lung carcinoma with neuroendocrine features, presenting with the full clinical picture of paraneoplastic opsoclonus-myoclonus syndrome. The patient had an unexpectedly dramatic resolution of the neurologic dysfunction after receiving antineoplastic treatment. Symptom improvement paralleled a progressive decline of serum ANNA-2 antibody titers to undetectable levels.

Paraneoplastic opsoclonus-myoclonus syndrome associated with malignant fibrous histiocytoma: neuropathological findings

Paraneoplastic syndromes related to soft tissue tumors are very uncommon and an association of paraneoplastic diseases with a malignant fibrous histiocytoma (MFH) has not been reported so far. Opsoclonus-myoclonus is a rare paraneoplastic nervous system syndrome, that was well documented in adult patients with neoplasms particularly of the lung and breast. A 77-year-old woman developed typical opsoclonus-myoclonus syndrome and rapidly progressed to coma. The opsoclonus and generalized myoclonus continued until the patient's death seven months later. An autopsy examination identified a pleomorphic MFH in the retroperitoneum without a metastatic spread. Microscopic examination of the cerebellum revealed an atrophy of the granular layer along with a marked patchy loss of Purkinje cells, and a loss of neurons in the cerebellar nuclei accompanied by distinct peridental demyelination and astrogliosis. A moderate loss of neurons and neuronal chromatolysis were observed also in the inferior olivary nuclei. However, the omnipause neurons of the nucleus raphe interpositus, that are supposed to be responsible for opsoclonus generation under pathological conditions, as well as ocular brain stem nuclei were all intact. We failed to prove the presence of known antineuronal anti-Yo, anti-Hu or anti-Ri autoantibodies in both serum and cerebrospinal fluid (CSF) of the patient. However, the confirmation of the intrathecal IgG synthesis by oligoclonal bands in CSF and the immunohistochemical detection of IgG deposits on membranes of Purkinje cells, neurons of cerebellar granular layer and in cerebellar nuclei in our case support the presumed autoimmune nature of the disease.