Christian A. Vedeler

The extent and pattern of demyelination in the cerebral cortex was determined in 78 tissue blocks from the brains of 20 multiple sclerosis (MS) patients and 28 tissue blocks from 7 patients without neurological disease. Tissue blocks from 4 predetermined areas (cingulate gyrus, frontal, parietal, and temporal lobe) were studied, irrespective of macroscopically evident MS plaques. All tissue blocks contained cerebral cortex and periventricular and/or subcortical white matter. One hundred and nine demyelinating lesions were detected in the cerebral cortex, of which 92 (84.4%) were purely intracortical and 17 (15.6%) were lesions extending through both white and gray matter areas. In 5 of the 20 MS brains, subpial demyelination was extensive in the 4 widely spaced cortical areas studied, thus considered to represent a general cortical subpial demyelination. The percentage of demyelinated area was significantly higher in the cerebral cortex (mean 26.5%, median 14.1%) than in white matter (mean 6.5%, median 0%) (p = 0.001). Both gray and white matter demyelination was more prominent in the cingulate gyrus than in the other areas examined (p < 0.05). These results indicate that the cerebral cortex is likely to be a predilection site for MS lesions and identify general cortical subpial demyelination as a distinct pattern occurring in a significant subpopulation of MS patients.

OBJECTIVE: The contemporary diagnosis of paraneoplastic neurologic syndromes (PNSs) requires an increasing understanding of their clinical, immunologic, and oncologic heterogeneity. The 2004 PNS criteria are partially outdated due to advances in PNS research in the last 16 years leading to the identification of new phenotypes and antibodies that have transformed the diagnostic approach to PNS. Here, we propose updated diagnostic criteria for PNS. METHODS: A panel of experts developed by consensus a modified set of diagnostic PNS criteria for clinical decision making and research purposes. The panel reappraised the 2004 criteria alongside new knowledge on PNS obtained from published and unpublished data generated by the different laboratories involved in the project. RESULTS: The panel proposed to substitute "classical syndromes" with the term "high-risk phenotypes" for cancer and introduce the concept of "intermediate-risk phenotypes." The term "onconeural antibody" was replaced by "high risk" (>70% associated with cancer) and "intermediate risk" (30%-70% associated with cancer) antibodies. The panel classified 3 levels of evidence for PNS: definite, probable, and possible. Each level can be reached by using the PNS-Care Score, which combines clinical phenotype, antibody type, the presence or absence of cancer, and time of follow-up. With the exception of opsoclonus-myoclonus, the diagnosis of definite PNS requires the presence of high- or intermediate-risk antibodies. Specific recommendations for similar syndromes triggered by immune checkpoint inhibitors are also provided. CONCLUSIONS: The proposed criteria and recommendations should be used to enhance the clinical care of patients with PNS and to encourage standardization of research initiatives addressing PNS.

BACKGROUND: paraneoplastic neurological syndromes (PNS) almost invariably predate detection of the malignancy. Screening for tumours is important in PNS as the tumour directly affects prognosis and treatment and should be performed as soon as possible. OBJECTIVES: an overview of the screening of tumours related to classical PNS is given. Small cell lung cancer, thymoma, breast cancer, ovarian carcinoma and teratoma and testicular tumours are described in relation to paraneoplastic limbic encephalitis, subacute sensory neuronopathy, subacute autonomic neuropathy, paraneoplastic cerebellar degeneration, paraneoplastic opsoclonus-myoclonus, Lambert-Eaton myasthenic syndrome (LEMS), myasthenia gravis and paraneoplastic peripheral nerve hyperexcitability. METHODS: many studies with class IV evidence were available; one study reached level III evidence. No evidence-based recommendations grade A-C were possible, but good practice points were agreed by consensus. RECOMMENDATIONS: the nature of antibody, and to a lesser extent the clinical syndrome, determines the risk and type of an underlying malignancy. For screening of the thoracic region, a CT-thorax is recommended, which if negative is followed by fluorodeoxyglucose-positron emission tomography (FDG-PET). Breast cancer is screened for by mammography, followed by MRI. For the pelvic region, ultrasound (US) is the investigation of first choice followed by CT. Dermatomyositis patients should have CT-thorax/abdomen, US of the pelvic region and mammography in women, US of testes in men under 50 years and colonoscopy in men and women over 50. If primary screening is negative, repeat screening after 3-6 months and screen every 6 months up till 4 years. In LEMS, screening for 2 years is sufficient. In syndromes where only a subgroup of patients have a malignancy, tumour markers have additional value to predict a probable malignancy.

The present study examined the extent and distribution of lymphocyte infiltration in demyelinated lesions in the cerebral cortex of multiple sclerosis (MS) patients. Tissue sections from the brain of 10 MS patients and five patients without neurological disease were double labeled for myelin basic protein and the lymphocyte markers CD3, CD4, CD8, CD45RO, and CD20. The highest density of CD3-positive T cells was found in MS white matter lesions (40.4/10 high power fields (hpf)). Fewer T cells were detected in cortical lesions that extended through both white and gray matter (12.1/10 hpf; P < 0.001). The lowest number of T cells was detected in intracortical demyelinated lesions (1.1/10 hpf). This was equal to the lymphocyte density in nondemyelinated cerebral cortex within the same tissue block (1.1/10 hpf) or cerebral cortex in control brains (1.8/10 hpf). A similar distribution was found using the CD4, CD8, and CD45RO markers. CD20-positive B cells were scarce in all specimens examined. These data indicate that areas of intracortical demyelination in chronic MS are not associated with an increased number of lymphocytes, or an altered distribution of lymphocyte subsets, when compared with control areas in MS and control patients. This finding indicates that the extent of lymphocyte infiltration in MS lesions is dependent on lesion location.

Paraneoplastic neurological syndromes (PNS) are remote effects of cancer on the nervous system. An overview of the management of classical PNS, i.e. paraneoplastic limbic encephalitis, subacute sensory neuronopathy, paraneoplastic cerebellar degeneration, paraneoplastic opsoclonus-myoclonus, Lambert-Eaton myasthenic syndrome and paraneoplastic peripheral nerve hyperexcitability is given. Myasthenia gravis and paraproteinemic neuropathies are not included in this report. No evidence-based recommendations were possible, but good practice points were agreed by consensus. Urgent investigation is indicated, especially in central nervous system (CNS) syndromes, to allow tumour therapy to be started early and prevent progressive neuronal death and irreversible disability. Onconeural antibodies are of great importance in the investigation of PNS and can be used to focus tumour search. PDG-PET is useful if the initial radiological tumour screen is negative. Early detection and treatment of the tumour is the approach that seems to offer the greatest chance for PNS stabilization. Immune therapy usually has no or modest effect on the CNS syndromes, whereas such therapy is beneficial for PNS affecting the neuromuscular junction. Symptomatic therapy should be offered to all patients with PNS.