CV2/CRMP5-antibody-related Paraneoplastic Optic Neuropathy Associated with Small-cell Lung Cancer

Meningeal Carcinomatosis Presenting with Bilateral Loss of Vision

Meningeal carcinomatosis (MC) has an extremely poor prognosis and can present with various neurological symptoms. A 68-year-old man presented to our hospital with a 1 month history of headache and nausea followed by sudden decrease in vision in both eyes. Whilst being examined in the ophthalmology department he lost consciousness and had a generalised tonic clonic seizure. Accordingly, he was transferred to the Emergency Department. Head magnetic resonance imaging showed hydrocephalus. Abdominal contrast-enhanced computed tomography scanning reported changes suggestive of gastric carcinoma. Cerebrospinal fluid cytological examination showed numerous atypical cells, leading to the diagnosis of MC. An upper gastrointestinal endoscopy revealed an advanced gastric tumour. Systemic chemotherapy was initiated, however, he died within 16 days of admission. At autopsy, poorly differentiated adenocarcinoma was identified in the subarachnoid space, however it had not invaded the brain parenchyma or optic chiasm. This is the first report of loss of vision being the first presenting symptom of new-onset gastric carcinoma with MC. Although rare, MC should be suspected in cases where patients present with sudden loss of vision and symptoms of meningeal irritation, where there are no ophthalmological findings to explain the vision loss.

Paraneoplastic vision loss

Paraneoplastic vision loss, which represents a small percentage of paraneoplastic neurologic syndromes, can be a blinding disease. Presenting visual symptoms are variable, making diagnosis challenging. History of the presenting illness, ocular examination, and utilization of various modalities, such as automated perimetry, ocular coherence tomography, and electroretinogram allow for localization of vision loss to the optic nerves or retina, guiding in diagnosis and management. Paraneoplastic vision loss is often painless, bilateral, and subacute, and accompanies other neurologic symptoms but can be the first presenting symptom. Paraneoplastic optic neuropathy has been described in association with several antibodies, but most commonly anti-CRMP5. Cancer-associated retinopathy is the most common paraneoplastic autoimmune retinopathy; however, melanoma-associated retinopathy and bilateral diffuse uveal melanocytic proliferation have also been described to be associated with a paraneoplastic process affecting the retina. Paraneoplastic visual loss is an expanding field and advances in research have improved phenotypic characterization; however, further work is needed to identify more reliable biomarkers of disease and to better understand the underlying mechanisms and management.

Rare Presentation and Diagnostic Challenge of a Germ Cell Tumor of the Yolk Sac Type

Opsoclonus-ataxia paraneoplastic syndrome (OAPS) is a rare neurological disorder often associated with malignancies. This case report highlights an unusual instance of OAPS linked to a yolk sac (germ cell) tumor, a correlation underrepresented in the medical literature. The patient presented with distinct neurological symptoms alongside mediastinal lymphadenopathies. The subsequent diagnostic journey revealed a yolk sac germ cell tumor. Following incisional biopsies and treatment, the patient experienced fluctuations in mental status, leading to challenges in initiating chemotherapy. Despite these complications, a multidisciplinary approach involving neurologists, oncologists, and hematologists was pivotal. The case emphasizes the complexities of managing OAPS in tandem with a germ cell tumor, underscoring the need for further research and highlighting the significance of specialized neurological evaluation in similar cases.

An overview on CV2/CRMP5 antibody-associated paraneoplastic neurological syndromes

Paraneoplastic neurological syndrome refers to certain malignant tumors that have affected the distant nervous system and caused corresponding dysfunction in the absence of tumor metastasis. Patients with this syndrome produce multiple antibodies, each targeting a different antigen and causing different symptoms and signs. The CV2/collapsin response mediator protein 5 (CRMP5) antibody is a major antibody of this type. It damages the nervous system, which often manifests as limbic encephalitis, chorea, ocular manifestation, cerebellar ataxia, myelopathy, and peripheral neuropathy. Detecting CV2/CRMP5 antibody is crucial for the clinical diagnosis of paraneoplastic neurological syndrome, and anti-tumor and immunological therapies can help to alleviate symptoms and improve prognosis. However, because of the low incidence of this disease, few reports and no reviews have been published about it so far. This article intends to review the research on CV2/CRMP5 antibody-associated paraneoplastic neurological syndrome and summarize its clinical features to help clinicians comprehensively understand the disease. Additionally, this review discusses the current challenges that this disease poses, and the application prospects of new detection and diagnostic techniques in the field of paraneoplastic neurological syndrome, including CV2/CRMP5-associated paraneoplastic neurological syndrome, in recent years.

An update on optic neuritis

Optic neuritis (ON) is the most common cause of subacute optic neuropathy in young adults. Although most cases of optic neuritis (ON) are classified as typical, meaning idiopathic or associated with multiple sclerosis, there is a growing understanding of atypical forms of optic neuritis such as antibody mediated aquaporin-4 (AQP4)-IgG neuromyelitis optica spectrum disorder (NMOSD) and the recently described entity, myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). Differentiating typical ON from atypical ON is important because they have different prognoses and treatments. Findings of atypical ON, including severe vision loss with poor recovery with steroids or steroid dependence, prominent optic disc edema, bilateral vision loss, and childhood or late adult onset, should prompt serologic testing for AQP4-IgG and MOG-IgG. Although the traditional division of typical and atypical ON can be helpful, it should be noted that there can be severe presentations of otherwise typical ON and mild presentations of atypical ON that blur these traditional lines. Rare causes of autoimmune optic neuropathies, such as glial fibrillary acidic protein (GFAP) and collapsin response-mediator protein 5 (CRMP5) autoimmunity also should be considered in patients with bilateral painless optic neuropathy associated with optic disc edema, especially if there are other accompanying suggestive neurologic symptoms/signs. Typical ON usually recovers well without treatment, though recovery may be expedited by steroids. Atypical ON is usually treated with intravenous steroids, and some forms, such as NMOSD, often require plasma exchange for acute attacks and long-term immunosuppressive therapy to prevent relapses. Since treatment is tailored to the cause of the ON, elucidating the etiology of the ON is of the utmost importance.

Serum and Cerebrospinal Fluid Testing in Optic Neuropathy Patients with Malignant Tumors

Purpose. To evaluate the value of serum and cerebrospinal fluid (CSF) testing in optic neuropathy (ON) patients with malignant tumors. Methods. Fourteen patients clinically diagnosed as ON with malignant tumors but without intracranial or orbital mass in MRI were included in this study. Detailed medical records including medical history, complete ophthalmic examination, colour fundus photography, visual field test, orbital MRI examination, serum and CSF testing data were collected and analyzed. The diagnosis of paraneoplastic optic neuropathy (PON) based on the 2004 recommended criteria of the paraneoplastic syndrome- Euronetwork consortium for paraneoplastic neurological disorders, and current adaption for neuropathies. All patients underwent serum tests for pathogens and autoantibodies including antinuclear antibodies, anticardiolipin antibodies, antineutrophil cytoplasmic antibodies, AQP4-Ab and MOG-Ab, as well as CSF tests for malignant cells under microscope. Serum paraneoplastic antibodies were detected in PON patients. Monkey cerebellar tissue-based assay was used to detect unknown serum anti-neuron antibodies in PON patients with negative paraneoplastic antibody testing results. Results. Fourteen ON patients were classified as four groups based on their clinical and MRI characteristics, as well as serum and CSF testing results: [1] definite PON, 6 cases (11 eyes); [2] possible PON, 3 case (5 eyes); [3] meningeal carcinomatosis-associated optic neuropathy (MCON), 4 cases (6 eyes); [4] infiltrative optic neuropathy (ION), 2 cases (2 eyes). Malignant cells were found under microscope in CSF samples from MCON and ION patients, contrast to no malignant cells in CSF samples from PON cases. All 14 ON patients with malignant tumors showed negative results in serum tests for pathogens and autoantibodies. Serum paraneoplastic antibodies were tested in PON patients, anti- CV2, anti-Yo, and anti- amphiphysin were detected positive in 2, 1, and 1 case, respectively, in definite PON group, whereas no serum paraneoplastic antibody detected in possible PON group. Two unknown serum antineuronal antibodies (an anti- Purkinje cell antibody and an anti-granular cell antibody) were detected using monkey cerebellar tissue-based assay in 2 of 5 PON patients with negative paraneoplastic antibody test results. Conclusions. Serum and CSF tests are of great importance in differentiating different subtypes of ON with malignant tumors. Current diagnosis of PON still depends on combination of clinical and MRI manifestations, as well as serum and CSF tests. Tissue-based assay may help to detect new biomarkers for ON etiology and diagnosis.

Application of optic neuro-ophthalmology imaging in latent meningeal metastases of lung cancer

Latent intracranial meningeal metastases (IMM) of lung cancer is difficult to determine, yet it is critical to do so given that it impacts the treatment agent. Studies on this disease are rare, thus necessitating further investigation. As a case study, we will explore the application of optic neuroimaging in IMM. A 62-year-old female patient was diagnosed with lung adenocarcinoma, which had progressed to osseous metastasis. During the course of chemotherapy, the patient had bilateral vision loss and paralysis of extraocular muscles. Ophthalmologists ruled out disease of the retina and suspected intracranial metastasis; however, brain-enhanced magnetic resonance angiography and magnetic resonance venography were normal. Given the patient's severe osteoarthropathy and poor physical condition, she refused to undergo a lumbar puncture examination. Optic neuro-ophthalmology imaging was ultimately used. Utilizing optical coherence tomography, we found that the basement membrane layer in the papilledema was protruding up towards the vitreous cavity. To assist in visualization, the optic nerve sheath was enhanced with optic magnetic resonance imaging. With these methods, the dural metastasis was identified, the treatment agent was changed for the patient, and she had a successful recovery. Thus, optic neuro-ophthalmology imaging should be recommended for patients who are in the latent course of dural metastasis, and it could also be used to evaluate therapeutic efficacy.

Optic neuritis classification in 2021

Optic neuritis (ON) can be associated with inflammatory disease of the central nervous system or can be isolated, with or without relapse. It can also be associated with infectious or systemic disease. These multiple associations based on a variety of clinical, radiological, and biological criteria that have changed over time have led to overlapping phenotypes: a single ON case can be classified in several ways simultaneously or over time. As early, intensive treatment is often required, its diagnosis should be rapid and precise. In this review, we present the current state of knowledge about diagnostic criteria for ON aetiologies in adults and children, we discuss overlapping phenotypes, and we propose a homogeneous classification scheme. Even if distinctions between typical and atypical ON are relevant, their phenotypes are largely overlapping, and clinical criteria are neither sensitive enough, nor specific enough, to assure a diagnosis. For initial cases of ON, clinicians should perform contrast enhanced MRI of the brain and orbits, cerebral spinal fluid analysis, and biological analyses to exclude secondary infectious or inflammatory ON. Systematic screening for MOG-IgG and AQP4-IgG IgG is recommended in children but is still a matter of debate in adults. Early recognition of neuromyelitis optica spectrum disorder, MOG-IgG-associated disorder, and chronic relapsing idiopathic optic neuritis is required, as these diagnoses require therapies for relapse prevention that are different from those used to treat multiple sclerosis.

Anti-CV2/CRMP5 antibody-positive paraneoplastic neurological syndromes with chronic intestinal pseudo-obstruction in a small-cell lung cancer patient: a case report and literature review

Patients with anti-CV2/collapsin response mediator protein (CRMP)5 antibodies present with more frequent chorea, cerebellar ataxia, uveo/retinal symptoms, and Lambert–Eaton myasthenic syndrome or myasthenia gravis. Chronic intestinal pseudo-obstruction (CIPO) is an intestinal motility dysfunction disease dysmotility that is caused by a neuromuscular disease with recurrent or persistent intestinal obstruction in the absence of mechanical obstruction. We report the case of a patient with CRMP5 antibody-positive paraneoplastic neurological syndrome (PNS) that is associated with autonomic dysfunction (presenting most remarkably as CIPO). CIPO is one of the rarest forms of PNS. Some PNS patients who are positive for anti-CV2/CRMP5 antibodies may have fatal complications such as CIPO. To detect if PNS patients are at risk for CIPO, a timely diagnosis and appropriate treatment are required.

Paraneoplastic optic neuropathy secondary to adenocarcinoma of the lung

We describe an uncommon cause of paraneoplastic optic neuropathy in adenocarcinoma of the lung. A 45-year-old healthy woman presented with seizure and encephalitis, followed by an acute visual loss in both eyes for 1 week. Her visual acuity was no perception of light in the right eye and hand movement in the left eye. There was a generalised restriction of extraocular muscle movements in both eyes. Funduscopy showed a bilateral pale optic disc. A paraneoplastic antigen autoimmune profile showed a positive anti-CV2/CRMP-5 antibody. CT of the thorax revealed the presence of right apical lung mass, confirmed to be adenocarcinoma through a biopsy. She was scheduled for lung lobectomy and chemotherapy. Unfortunately, her health deteriorated and she passed away eventually.

PARANEOPLASTIC OPTIC NEUROPATHY AS AN INITIAL CLINICAL MANIFESTATION OF SMALL CELL LUNG CANCER. A CASE REPORT

Paraneoplastic optic neuropathy (PON) is a very rare condition. In this study, a case of PON whose first complaint was painless vision loss in one eye is presented. In the follow-up of our case, optic neuropathy developed in the fellow eye. Electromyography examination performed due to diffuse body pain and motor loss in the left extremity is compatible with peripheral sensorimotor polyneuropathy. Lung biopsy was planned due to EMG result and and lymphadenopathy detection in thorax computed tomography (CT). The biopsy result of the patient was reported as nonspecific hyperplasia. As the patient's complaints increased, the paraneoplastic antibody panel was requested and CV2 / CRMP5 antibody was found positive. Thereupon, as a result of repeated biopsy, our patient was diagnosed with small cell lung cancer. We think that paraneoplastic optic neuropathy should be considered in the differential diagnosis in patients with advanced age, smoking, painless subacute vision loss, optic disc swelling, and we should insist on research in this direction as in our case.

Ocular Paraneoplastic Syndromes

Ocular-involving paraneoplastic syndromes present a wide variety of clinical symptoms. Understanding the background pathophysiological and immunopathological factors can help make a more refined differential diagnosis consistent with the signs and symptoms presented by patients. There are two main pathophysiology arms: (1) autoimmune pathomechanism, which is presented with cancer-associated retinopathy (CAR), melanoma-associated retinopathy (MAR), cancer-associated cone dysfunction (CACD), paraneoplastic vitelliform maculopathy (PVM), and paraneoplastic optic neuritis (PON), and (2) ectopic peptides, which is often caused by tumor-expressed growth factors (T-exGF) and presented with bilateral diffuse uveal melanocytic proliferation (BDUMP). Meticulous systematic analysis of patient symptoms is a critical diagnostic step, complemented by multimodal imaging, which includes fundus photography, optical coherent tomography, fundus autofluorescence, fundus fluorescein angiography, electrophysiological examination, and sometimes fundus indocyjanin green angiography if prescribed by the clinician. Assessment of the presence of circulating antibodies is required for diagnosis. Antiretinal autoantibodies are highly associated with visual paraneoplastic syndromes and may guide diagnosis by classifying clinical manifestations in addition to monitoring treatment.

Anti-CV2 Autoimmune Encephalitis With Parkinson-Like Symptoms and Bilateral Leukoencephalopathy-A Case Report

Objective: To present a patient with anti-CV2 autoimmune encephalitis admitted for Parkinson-like symptoms and bilateral leukoencephalopathy.

Case report: The patient was admitted for Parkinson-like symptoms combined with loss of taste. Serum anti-CV2 antibody was positive. Cranial magnetic resonance imaging revealed bilateral leukoencephalopathy. Breast cancer was detected by positron emission tomography (PET) and ultrasound. Immunotherapy was not performed. Modified radical mastectomy revealed a pT1cN0M0 breast cancer, positive for estrogen and progesterone receptors, and HER2 negative. The resting tremors disappeared by 1 week after surgery. The modified Rankin score (mRS) was four before surgery, and decreased to one at 9 months after surgery.

Conclusion: Anti-CV2 autoimmune encephalitis can present as Parkinsonism with bilateral leukoencephalopathy on MRI. PET scanning can be useful to reveal an occult cancer. Treatment of the cancer may improve the paraneoplastic neurological syndrome without the need of immunosuppressive therapy.

Paraneoplastic Syndromes in Neuro-ophthalmology

PURPOSE OF REVIEW

This article discusses the varied types of paraneoplastic syndromes that commonly have neuro-ophthalmologic manifestations. Diagnostic considerations and therapeutic options for individual diseases are also discussed.

RECENT FINDINGS

Paraneoplastic syndromes can affect the afferent and efferent visual systems. Paraneoplastic syndromes may result in reduced visual acuity from retinal degeneration, alterations in melanocyte proliferation and uveal thickening, or acquired nystagmus. Ocular motor abnormalities related to paraneoplastic syndromes may present with symptoms from opsoclonus or from neuromuscular junction disease. Diagnosis remains challenging, but serologic identification of some specific antibodies may be helpful or confirmatory. Treatment, in addition to directed therapies against the underlying cancer, often requires systemic corticosteroids, plasma exchange, or immunosuppression, but some specific syndromes improve with use of targeted pharmacologic therapy.

SUMMARY

Diagnosis and therapy of paraneoplastic syndromes presenting with neuro-ophthalmic symptoms remain a challenge, but strategies are evolving and new approaches are on the horizon.

Autoantibodies as diagnostic biomarkers for lung cancer: A systematic review

Lung cancer (LC) accounts for the largest number of tumor-related deaths worldwide. As the overall 5-year survival rate of LC is associated with its stages at detection, development of a cost-effective and noninvasive cancer screening method is necessary. We conducted a systematic review to evaluate the diagnostic values of single and panel tumor-associated autoantibodies (TAAbs) in patients with LC. This review included 52 articles with 64 single TAAbs and 19 with 20 panels of TAAbs. Enzyme-linked immunosorbent assays (ELISA) were the most common detection method. The sensitivities of single TAAbs for all stages of LC ranged from 3.1% to 92.9% (mean: 45.2%, median: 37.1%), specificities from 60.6% to 100% (mean: 88.1%, median: 94.9%), and AUCs from 0.416 to 0.990 (mean: 0.764, median: 0.785). The single TAAb with the most significant diagnostic value was the autoantibody against human epididymis secretory protein (HE4) with the maximum sensitivity 91% for NSCLC. The sensitivities of the panel of TAAbs ranged from 30% to 94.8% (mean: 76.7%, median: 82%), specificities from 73% to 100% (mean: 86.8%, median: 89.0%), and AUCs from 0.630 to 0.982 (mean: 0.821, median: 0.820), and the most significant AUC value in a panel (M13 Phage 908, 3148, 1011, 3052, 1000) was 0.982. The single TAAb with the most significant diagnostic calue for early stage LC, was the autoantibody against Wilms tumor protein 1 (WT1) with the maximum sensitivity of 90.3% for NSCLC and its sensitivity and specificity in a panel (T7 Phage 72, 91, 96, 252, 286, 290) were both above 90.0%. Single or TAAbs panels may be useful biomarkers for detecting LC patients at all stages or an early-stage in high-risk populations or health people, but the TAAbs panels showed higher detection performance than single TAAbs. The diagnostic value of the panel of six TAAbs, which is higher than the panel of seven TAAbs, may be used as potential biomarkers for the early detection of LC and can probably be used in combination with low-dose CT in the clinic.