Cerebral amyloid angiopathy associated with primary angiitis of the central nervous system: report of 2 cases and review of the literature

Cerebral amyloid angiopathy and the immune system

Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of amyloid protein in the walls of cerebral blood vessels. This deposition of amyloid causes damage to the cerebral vasculature, resulting in blood-brain barrier disruption, cerebral hemorrhage, cognitive decline, and dementia. The role of the immune system in CAA is complex and not fully understood. While the immune system has a clear role in the rare inflammatory variants of CAA (CAA related inflammation and Abeta related angiitis), the more common variants of CAA also have immune system involvement. In a protective role, immune cells may facilitate the clearance of beta-amyloid from the cerebral vasculature. The immune system can also contribute to CAA pathology, promoting vascular injury, blood-brain barrier breakdown, inflammation, and progression of CAA. In this review, we summarize the role of the immune system in CAA, including the potential of immune based treatment strategies to slow vascular disease in CAA and associated cognitive impairment, white matter disease progression, and reduce the risk of cerebral hemorrhage. HIGHLIGHTS: The immune system has a role in cerebral amyloid angiopathy (CAA) which is summarized in this review. There is an inflammatory response to beta-amyloid that may contribute to brain injury and cognitive impairment. Immune cells may facilitate the clearance of beta-amyloid from the cerebral vasculature. Improved understanding of the immune system in CAA may afford novel treatment to improve outcomes in patients with CAA.

Identifying diagnostic and prognostic factors in cerebral amyloid angiopathy-related inflammation: A systematic analysis of published and seven new cases

AIMS

Cerebral amyloid angiopathy (CAA)-related inflammation (CAA-RI) is a potentially reversible manifestation of CAA, histopathologically characterised by transmural and/or perivascular inflammatory infiltrates. We aimed to identify clinical, radiological and laboratory variables capable of improving or supporting the diagnosis of or predicting/influencing the prognosis of CAA-RI and to retrospectively evaluate different therapeutic approaches.

METHODS

We present clinical and neuroradiological observations in seven unpublished CAA-RI cases, including neuropathological findings in two definite cases. These cases were included in a systematic analysis of probable/definite CAA-RI cases published in the literature up to 31 December 2021. Descriptive and associative analyses were performed, including a set of clinical, radiological and laboratory variables to predict short-term, 6-month and 1-year outcomes and mortality, first on definite and second on an expanded probable/definite CAA-RI cohort.

RESULTS

Data on 205 definite and 100 probable cases were analysed. CAA-RI had a younger symptomatic onset than non-inflammatory CAA, without sex preference. Transmural histology was more likely to be associated with the co-localisation of microbleeds with confluent white matter hyperintensities on magnetic resonance imaging (MRI). Incorporating leptomeningeal enhancement and/or sulcal non-nulling on fluid-attenuated inversion recovery (FLAIR) enhanced the sensitivity of the criteria. Cerebrospinal fluid pleocytosis was associated with a decreased probability of clinical improvement and longer term positive outcomes. Future lobar haemorrhage was associated with adverse outcomes, including mortality. Immunosuppression was associated with short-term improvement, with less clear effects on long-term outcomes. The superiority of high-dose over low-dose corticosteroids was not established.

CONCLUSIONS

This is the largest retrospective associative analysis of published CAA-RI cases and the first to include an expanded probable/definite cohort to identify diagnostic/prognostic markers. We propose points for further crystallisation of the criteria and directions for future prospective studies.

Primary Angiitis of the Central Nervous System in Adults: A Comprehensive Review of 76 Biopsy-Proven Case Reports

Purpose

Primary angiitis of the adult central nervous system (PACNS) is an increasingly recognized but limited disease. Using previous case reports, we sought to summarize the clinical symptoms, imaging manifestations, treatment, and prognosis of patients with biopsy-confirmed PACNS to guide clinical diagnosis and management.

Methods

We searched the Web of Science database for studies published from January 2000 to April 2023, with the language set to English and the document type limited to [Article or Review or Letter or Editorial Material]. A systematic review of all case reports met the inclusion and exclusion criteria was performed. These patients' clinical, pathological, and imaging characteristics were analyzed, and treatment and prognostic data were summarized.

Results

We analyzed 69 articles, including 76 patients with biopsy-confirmed PACNS. And 57.9% of the patients were male, the median age at presentation was 47.0 years, and focal neurological deficits were the most common symptom in patients (78.9%), followed by headache (52.6%). The median duration of biopsy was 1.1 months, of which 49 (64.5%) patients were lymphocytic, 13 (17.1%) were granulomatous, 11 (14.5%) were amyloidotic, and 3 (3.9%) were necrotizing PACNS. Relapse events occurred in 41 (53.9%) patients, including 34 (44.2%) relapses and 8 (10.5%) deaths. Univariate logistic regression analysis revealed that symptomatic epilepsy, prolonged biopsy time window, and CD20 expression in pathological tissues might be independent risk factors for recurrent events in patients (HR=4.69, 95% CI: 1.51-14.54, p=0.007; HR=1.11, 95% CI: 1.00-1.22, p=0.043; HR=5.33, 95% CI: 1.07-26.61, p=0.041).

Conclusion

Adult PACNS is associated with frequent relapses and high mortality. Symptomatic epilepsy, prolonged biopsy time window, and CD20 expression in pathological tissue may be associated with recurrent events.

Pseudotumoral Presentation of Cerebral Amyloid-Beta Angiopathy: Case Report and Review of Literature

OBJECTIVE

Cerebral amyloid angiopathy-related inflammation (CAA-RI) is a rare and potentially treatable encephalopathy that usually affects people older than 50 years old and has an acute or subacute clinical presentation characterized by rapidly evolving cognitive decline, focal deficits and seizures. In a small subset of patients the disease can adopt a pseudotumoral form in the neuroimages that represents a very difficult diagnostic challenge.

METHODS

Here in we report a patient with a tumour-like presentation of histopathologically confirmed CAA-RI.

RESULTS

We also conducted a search and reviewed the clinical and radiological features of 41 cases of pseudotumoral CAA-RI previously reported in the literature in order to identify those characteristics that should raise diagnostic suspicions of the disease, there by avoiding unnecessary surgical treatments.

CONCLUSION

The therapy of CAA-RI with steroids is usually effective and clinical and radiological remission can be achieved in the first month in approximately 70% of cases.

Association Between Immunosuppressive Treatment and Outcomes of Cerebral Amyloid Angiopathy-Related Inflammation

IMPORTANCE

Cerebral amyloid angiopathy-related inflammation (CAA-ri), a distinct subtype of cerebral amyloid angiopathy, is characterized by an autoimmune reaction to cerebrovascular β-amyloid deposits. Outcomes and response to immunosuppressive therapy for CAA-ri are poorly understood.

OBJECTIVE

To identify clinical, neuroimaging, laboratory, pathologic, or treatment-related associations with outcomes after an episode of CAA-ri.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study of prospectively identified individuals who presented from July 3, 1998, to November 27, 2017, with a median follow-up of 2.7 years (interquartile range, 1.0-5.5 years). The study included 48 consecutive patients with CAA-ri meeting diagnostic criteria who had at least 1 disease episode and subsequent outcome data. No patients refused or were excluded.

EXPOSURES

Prespecified candidate variables were immunosuppressive therapies, cerebrospinal fluid pleocytosis, magnetic resonance imaging findings of recent infarcts or contrast enhancement, and histopathologic evidence of vessel wall inflammation.

MAIN OUTCOMES AND MEASURES

Clinical improvement and worsening were defined by persistent changes in signs or symptoms, radiographic improvement by decreased subcortical foci of T2 hyperintensity or T1 enhancement, and radiographic worsening by increased subcortical T2 hyperintensity, T1 enhancement, or infarcts. Disease recurrence was defined as new-onset clinical symptoms associated with new imaging findings.

RESULTS

The 48 individuals in the study included 29 women and had a mean (SD) age of 68.9 (9.9) years. Results of presenting magnetic resonance imaging revealed that 10 of 29 patients with CAA-ri (34%) had T1 contrast enhancement, 30 of 32 (94%) had subcortical T2 hyperintensity (22 of 30 [73%] asymmetric), 7 of 32 (22%) had acute or subacute punctate infarcts, and 27 of 31 (87%) had microbleeds. Immunosuppressive treatments after first episodes included corticosteroids (33 [69%]), cyclophosphamide (6 [13%]), and mycophenolate (2 [4%]); 14 patients (29%) received no treatment. Clinical improvement and radiographic improvement were each more likely in individuals treated with an immunosuppressive agent than with no treatment (clinical improvement: 32 of 34 [94%] vs 7 of 14 [50%]; odds ratio, 16.0; 95% CI, 2.72-94.1; radiographic improvement: 24 of 28 [86%] vs 4 of 14 [29%]; odds ratio, 15.0; 95% CI, 3.12-72.1). Recurrence was less likely if CAA-ri was treated with any immunosuppressant agent than not (9 of 34 [26%] vs 10 of 14 [71%]; hazard ratio, 0.19; 95% CI, 0.07-0.48). When controlling for treatment, no variables were associated with outcomes aside from an association between APOE ɛ4 and radiographic improvement (odds ratio, 4.49; 95% CI, 1.11-18.2).

CONCLUSIONS AND RELEVANCE

These results from a relatively large series of patients with CAA-ri support the effectiveness of immunosuppressive treatment and suggest that early treatment may both improve the initial disease course and reduce the likelihood of recurrence. These results raise the possibility that early blunting of CAA-ri and the autoimmune response may have long-term benefits for the subsequent disease course.

Cerebral amyloid angiopathy associated with inflammation: A systematic review of clinical and imaging features and outcome

Background

Cerebral amyloid angiopathy associated with inflammation is an increasingly recognized condition, characterized by an inflammatory response to the vascular deposits of β-amyloid within the brain that are the hallmark of cerebral amyloid angiopathy. Two main patterns of this inflammatory response have been identified to date: one involving a perivascular inflammatory cell infiltrate (cerebral amyloid angiopathy-related inflammation); the other a transmural vasculitic process (A-beta related angiitis). Unlike cerebral amyloid angiopathy itself, which predisposes to intracerebral hemorrhage and has no known treatment, cerebral amyloid angiopathy associated with inflammation typically presents in diverse ways and diagnosis may be challenging and delayed.

Aims

We sought to summarize the clinical features, imaging appearances and available data on outcome and treatment responses, using information derived from a systematic review of pathologically proven cases of cerebral amyloid angiopathy associated with inflammation.

Summary of review

We identified 213 distinct pathologically proven cases of cerebral amyloid angiopathy-related inflammation/A-beta related angiitis, from 104 publications. The clinical presentation, imaging features, pathology, treatment, and outcomes of cerebral amyloid angiopathy associated with inflammation are described.

Conclusions

Cerebral amyloid angiopathy associated with inflammation is an important and increasingly recognized clinical condition, which affects the older patient population and presents most commonly with cognitive decline, seizures, and headaches. Future research is required to develop and validate diagnostic criteria and determine optimum treatment strategies.

Cerebrospinal Fluid Alzheimer's Disease Biomarkers in Cerebral Amyloid Angiopathy-Related Inflammation

BACKGROUND

Decreased cerebrospinal fluid (CSF) amyloid-β 1-40 (Aβ40) and amyloid-β 1-42 (Aβ42) and increased total and phosphorylated tau (t-tau, p-tau) concentrations have been described in cerebral amyloid angiopathy (CAA).

OBJECTIVE

Our aim was to analyze these biomarkers in patients with CAA-related inflammation (CAA-I).

METHODS

We prospectively recruited nine patients with acute phase CAA-I fulfilling Chung criteria. CSF was analyzed for t-tau, p-tau, Aβ42, and Aβ40. Data were compared to controls (n = 14), patients with Alzheimer's disease (AD, n = 42), CAA (n = 10), and primary angiitis of the central nervous system (PACNS, n = 3).

RESULTS

For the CAA-I group, statistically significant differences were: lower Aβ42 (p = 0.00053) compared to the control group; lower t-tau (p = 0.018), p-tau (p <  0.001), and Aβ40 (p <  0.001) compared to AD; lower Aβ42 (p = 0.027) compared to CAA; lower Aβ42 (p = 0.012) compared to PACNS. Nearly significantly lower Aβ40 (p = 0.051) and higher t-tau (p = 0.051) were seen in CAA-I compared to controls.

CONCLUSION

CSF biomarkers profile similar to that of CAA was observed in CAA-I (with even lower levels of Aβ42 compared to CAA). Based on our findings, high p-tau seems more specific for AD, whereas low Aβ42 differentiates CAA-I from CAA, PACNS, and controls, and low Aβ40 differentiates CAA-I from AD.

Pseudotumoral presentation of cerebral amyloid angiopathy-related inflammation

OBJECTIVE

To identify the clinical and radiologic features that should raise suspicion for the pseudotumoral presentation of cerebral amyloid angiopathy-related inflammation (CAA-I).

METHODS

We retrospectively reviewed the characteristics of 5 newly diagnosed and 23 previously reported patients in whom the CAA-I imaging findings were initially interpreted as CNS neoplasms.

RESULTS

Most cases (85%) occurred in patients >60 years old. The clinical characteristics at presentation included subacute cognitive decline (50%), confusion (32%), focal deficits (32%), seizures (25%), and headaches (21%). Brain MRI demonstrated infiltrative white matter lesions that exhibited a loco-regional mass effect without parenchymal enhancement (93%). In general, these findings were interpreted as low-grade glioma or lymphoma. Eighteen patients (64%) underwent a biopsy, which was nondiagnostic in 4 patients (14%), and 6 patients (21%) underwent a surgical resection. The primary reason for the misinterpretation of the imaging findings was the absence of T2*-weighted gradient recalled echo (T2*-GRE) sequences on initial imaging (89%). When subsequently performed (39%), the T2*-GRE sequences demonstrated multiple characteristic cortical and subcortical microhemorrhages in all cases. Perfusion MRI and magnetic resonance spectroscopy (MRS), which were performed on a subset of patients, indicated markedly reduced relative cerebral blood flow and a normal metabolic ratio.

CONCLUSION

The identification of one or several nonenhancing space-occupying lesions, especially in elderly patients presenting with cognitive impairment, should raise suspicion for the pseudotumoral presentation of CAA-I and lead to T2*-GRE sequences. Perfusion MRI and MRS appear to be useful techniques for the differential diagnosis of this entity.

Cerebral Amyloid Angiopathy Associated with Inflammation: Report of 3 Cases and Systematic Review

INTRODUCTION

Cerebral amyloid angiopathy associated with inflammatory process (CAA-I) is a rare potentially treatable encephalopathy, characterized by an inflammatory response to vascular deposits of β-amyloid. We aimed to describe 3 clinical cases and perform a systematic review of all neuropathologically proved CAA-I case reports to describe its clinical and pathologic features and outcome under different treatments.

METHODS

We searched PubMed and Cochrane Library and screened references of included studies and review articles for additional citations. Outcome was classified at the last available follow-up by the modified Rankin Scale (mRS).

RESULTS

A total of 67 publications, reporting on 155 patients, were included. Mean age was 66.9 years, and 53.5% were men. The most common clinical presentation was cognitive dysfunction (48.0%) followed by headaches (38.7%), seizures (36.7%), and pyramidal signs (20.0%). Perivascular and vasculitic inflammation with granuloma was the most common pathologic pattern (27.5%). Eighty-six percent were treated with corticosteroids and 33.9% with cyclophosphamide. Forty-two percent regained independence (mRS score 0-2), whereas 20.5% were left with a severe handicap (mRS score 3-5) and 37.5% died. There were no statistically significant differences in outcome between patients treated with therapy with corticosteroids alone comparing with those treated with combination corticosteroids with cytostatic agents.

CONCLUSIONS

The most common clinical manifestation of CAA-I was cognitive dysfunction. The functional outcome was unfavorable in the majority of the patients, with death or severe disability in almost two third of the cases, despite treatment. No differences in outcome could be detected between patients treated with corticosteroids versus patients treated with cytostatics, combined with corticosteroids.

Aβ-related angiitis: comparison with CAA without inflammation and primary CNS vasculitis

OBJECTIVE

To analyze the clinical findings, response to therapy, and outcomes of patients with cerebral vascular amyloid-β (Aβ) deposition with and without inflammatory vascular infiltration.

METHODS

We report 78 consecutive patients with cerebral vascular Aβ deposition examined at Mayo Clinic Rochester over 25 years (1987 through 2011). Specimens reviewed by a neuropathologist showed 40 with vascular Aβ peptide without inflammation (cerebral amyloid angiopathy [CAA]), 28 with granulomatous vasculitis (Aβ-related angiitis or ABRA), and 10 with perivascular CAA-related inflammation. We also matched findings in 118 consecutive patients with primary CNS vasculitis (PCNSV) without Aβ seen over 25 years (1983 through 2007).

RESULTS

Compared to the 40 with CAA, the 28 with ABRA were younger at diagnosis (p = 0.05), had less altered cognition (p = 0.02), fewer neurologic deficits (p = 0.02), and fewer intracranial hemorrhages (<0.001), but increased gadolinium leptomeningeal enhancement (p = 0.01) at presentation, and less mortality and disability at last follow-up (p < 0.001). Compared with PCNSV, the 28 patients with ABRA were older at diagnosis (p < 0.001), had a higher frequency of altered cognition (p = 0.05), seizures/spells (p = 0.006), gadolinium leptomeningeal enhancement (p < 0.001), and intracerebral hemorrhage (p = 0.02), lower frequency of hemiparesis (p = 0.01), visual symptoms (p = 0.04), and MRI evidence of cerebral infarction (p = 0.003), but higher CSF protein levels (p = 0.03). Results of treatment and outcomes in ABRA and PCNSV were similar.

CONCLUSIONS

ABRA appears to represent a distinct subset of PCNSV.

Immune activation in amyloid-β-related angiitis correlates with decreased parenchymal amyloid-β plaque load

BACKGROUND

Primary angiitis of the central nervous system (PACNS) is a rare but serious condition. A fraction of patients suffering from PACNS concurrently exhibit pronounced cerebral amyloid angiopathy (CAA) which is characterized by deposits of amyloid-β (Aβ) in and around the walls of small and medium-sized arteries of the brain. PACNS with CAA has been identified as a distinct disease entity, termed Aβ-related angiitis (ABRA). Evidence points to an immune reaction to vessel wall Aβ as the trigger of vasculitis.

OBJECTIVE

To investigate whether the inflammatory response to Aβ has (1) any effect on the status of immune activation in the brain parenchyma and (2) leads to clearance of Aβ from brain parenchyma.

METHODS

We studied immune activation and Aβ load by quantitative immunohistochemical analysis in brain parenchyma adjacent to affected vessels in 11 ABRA patients and 10 matched CAA controls.

RESULTS

ABRA patients showed significantly increased immune activation and decreased Aβ loads in the brain parenchyma adjacent to affected vessels.

CONCLUSION

Our results are in line with the hypothesis of ABRA being the result of an excessive immune response to Aβ and show that this can lead to enhanced clearance of Aβ from the brain parenchyma by immune-mediated mechanisms.

Cerebral amyloid angiopathy-associated intracerebral hemorrhage: pathology and management

Amyloid angiopathy-associated intracerebral hemorrhage (ICH) comprises 12%-15% of lobar ICH in the elderly. This growing population has an increasing incidence of thrombolysis-related hemorrhages, causing the management of hemorrhages associated with cerebral amyloid angiopathy (CAA) to take center stage. A concise reference assimilating the pathology and management of this clinical entity does not exist. Amyloid angiopathy-associated hemorrhages are most often solitary, but the natural history often progresses to include multifocal and recurrent hemorrhages. Compared with other causes of ICH, patients with CAA-associated hemorrhages have a lower mortality rate but an increased risk of recurrence. Unlike hypertensive arteriolar hemorrhages that occur in penetrating subcortical vessels, CAA-associated hemorrhages are superficial in location due to preferential involvement of vessels in the cerebral cortex and meninges. This feature makes CAA-associated hemorrhages easier to access surgically. In this paper, the authors discuss 3 postulates regarding the pathogenesis of amyloid hemorrhages, as well as the established clinicopathological classification of amyloid angiopathy and CAA-associated ICH. Common inheritance patterns of familial CAA with hemorrhagic strokes are discussed along with the role of genetic screening in relatives of patients with CAA. The radiological characteristics of CAA are described with specific attention to CAA-associated microhemorrhages. The detection of these microhemorrhages may have important clinical implications on the administration of anticoagulation and antiplatelet therapy in patients with probable CAA. Poor patient outcome in CAA-associated ICH is associated with dementia, increasing age, hematoma volume and location, initial Glasgow Coma Scale score, and intraventricular extension. The surgical management strategies for amyloid hemorrhages are discussed with a review of published surgical case series and their outcomes with a special attention to postoperative hemorrhage.

Cerebral amyloid angiopathy-related inflammation presenting with steroid-responsive higher brain dysfunction: case report and review of the literature

A 56-year-old man noticed discomfort in his left lower limb, followed by convulsion and numbness in the same area. Magnetic resonance imaging (MRI) showed white matter lesions in the right parietal lobe accompanied by leptomeningeal or leptomeningeal and cortical post-contrast enhancement along the parietal sulci. The patient also exhibited higher brain dysfunction corresponding with the lesions on MRI. Histological pathology disclosed β-amyloid in the blood vessels and perivascular inflammation, which highlights the diagnosis of cerebral amyloid angiopathy (CAA)-related inflammation. Pulse steroid therapy was so effective that clinical and radiological findings immediately improved.CAA-related inflammation is a rare disease, defined by the deposition of amyloid proteins within the leptomeningeal and cortical arteries associated with vasculitis or perivasculitis. Here we report a patient with CAA-related inflammation who showed higher brain dysfunction that improved with steroid therapy. In cases with atypical radiological lesions like our case, cerebral biopsy with histological confirmation remains necessary for an accurate diagnosis.

Steroid responsive encephalopathy in cerebral amyloid angiopathy: a case report and review of evidence for immunosuppressive treatment

Cerebral amyloid angiopathy (CAA) is a common but often asymptomatic disease, characterized by deposition of amyloid in cerebral blood vessels. We describe the successful treatment of CAA encephalopathy with dexamethasone in a patient with CAA-related inflammation causing subacute progressive encephalopathy and seizures, which is an increasingly recognized subtype of CAA. The two pathological subtypes of CAA-related inflammation are described and a review of the literature is performed concerning immunosuppressive treatment of CAA-related inflammation with special attention to its pathological subtypes. Immunosuppressive therapy appears to be an appropriate treatment for CAA encephalopathy.

Primary central nervous system vasculitis: comparison of patients with and without cerebral amyloid angiopathy

OBJECTIVES

To describe the clinical features and outcomes of patients with primary central nervous system vasculitis (PCNSV) and cerebral amyloid angiopathy (CAA) from a large cohort of consecutive patients with PCNSV treated at a single institution.

METHODS

We identified 101 consecutive patients with PCNSV admitted between January 1983 and December 2003. PCNSV diagnoses were based on findings from a central nervous system (CNS) biopsy (n = 31) and conventional angiography (n = 70). CNS tissue specimens from 49 cases were examined histologically, and 49 were stained for amyloid deposits. Those with vascular amyloid deposits (CAA) were compared with those without histological evidence of amyloid deposition.

RESULTS

Eight cases (26%) with CNS biopsy specimens positive for PCNSV also showed findings of CAA. Compared with patients with PCNSV only, these patients were older at diagnosis, predominantly male, had a more acute onset, a higher frequency of cognitive dysfunction and showed prominent gadolinium-enhanced leptomeningeal lesions with MRI. Histologically, all had a granulomatous vascular inflammatory pattern. Six patients responded promptly to therapy. Outcomes at last follow-up were similar in the two groups.

CONCLUSIONS

PCNSV with CAA appears to form a clinical subset of PCNSV. The vasculitis influences the clinical findings to a greater degree than the presence of amyloid deposits in the vessels.

Limbic encephalitis and variants: classification, diagnosis and treatment

BACKGROUND AND OBJECTIVE

Recent studies suggest that a substantial number of patients with autoimmune limbic encephalitis may improve if properly diagnosed and treated. This is due, in part, to the increasing recognition of disorders that associate with antibodies to neuronal cell membrane antigens. This review focuses in these disorders, framed in a clinically useful immunologic classification of limbic encephalitis.

REVIEW SUMMARY

Patients with limbic encephalitis usually present with rapidly progressive short-term memory deficits, psychiatric symptoms, and seizures. After excluding viral and systemic autoimmune disorders, many patients with limbic encephalitis (paraneoplastic or not) have cerebrospinal fluid inflammatory findings, EEG or MRI abnormalities in the temporal lobes, and antineuronal antibodies. These antibodies are directed against 2 broad categories of antigens: (1) intracellular or classic paraneoplastic antigens, including Hu, Ma2, CV2/CRMP5, and amphiphysin among others, and (2) cell membrane antigens, including voltage-gated potassium channels, N-methyl-D-aspartate receptor, and others expressed in the neuropil of hippocampus and cerebellum (pending characterization). Whereas the disorders related to the first category of antibodies associate with cancer (lung, testis and other), prominent brain infiltrates of cytotoxic T-cells, and limited response to treatment, the disorders related to the second category of antibodies associate less frequently with cancer (thymoma, teratoma), seem to be antibody-mediated, and respond significantly better to immunotherapy.

CONCLUSIONS

Once considered an extremely rare disorder, almost always related to cancer, and refractory to treatment, limbic encephalitis is now regarded as a relatively frequent disorder, often unrelated to cancer, and with clinical-immunologic variants that respond to treatment.

Cerebral amyloid angiopathy presenting with vasculitic pathology

We present an elderly patient with an unusual extensive multifocal central nervous system mass lesion, with dramatic imaging changes but only minor disturbance of cerebral function. Cerebral biopsy revealed an unexpected finding of severe cerebral amyloid angiopathy with secondary florid vasculitic appearances, which is a very rare but recognised association. Immunosuppression has produced significant sustained clinical and radiological remission.