Cerebral Amyloid Angiopathy-related Inflammation Research Articles

Characterization of Clinical Course and Response to Treatment on Cerebral Amyloid Angiopathy-Related Inflammation

Characterization of Clinical Course and Response to Treatment on Cerebral Amyloid Angiopathy-Related Inflammation

No replicating evidence for anti-amyloid-β autoantibodies in cerebral amyloid angiopathy-related inflammation.

Elevated levels of anti-amyloid-β (anti-Aβ) autoantibodies in cerebrospinal fluid (CSF) have been proposed as a diagnostic biomarker for cerebral amyloid angiopathy-related inflammation (CAA-RI). We aimed to independently validate the immunoassay for quantifying these antibodies and evaluate its diagnostic value for CAA-RI. We replicated the immunoassay to detect CSF anti-Aβ autoantibodies using CSF from CAA-RI patients and non-CAA controls with unrelated disorders and further characterized its performance. Moreover, we conducted a literature review of CAA-RI case reports to investigate neuropathological and CSF evidence of the nature of the inflammatory reaction in CAA-RI. The assay demonstrated a high background signal in CSF, which increased and corresponded with higher total immunoglobulin G (IgG) concentration in CSF (rsp = 0.51, p = 0.02). Assay levels were not elevated in CAA-RI patients (n = 6) compared to non-CAA controls (n = 20; p = 0.64). Literature review indicated only occasional presence of B-lymphocytes and plasma cells (i.e., antibody-producing cells), alongside the abundant presence of activated microglial cells, T-cells, and other monocyte lineage cells. CSF analysis did not convincingly indicate intrathecal IgG production. We were unable to reproduce the reported elevation of anti-Aβ autoantibody concentration in CSF of CAA-RI patients. Our findings instead support nonspecific detection of IgG levels in CSF by the assay. Reviewed CAA-RI case reports suggested a widespread cerebral inflammatory reaction. In conclusion, our findings do not support anti-Aβ autoantibodies as a diagnostic biomarker for CAA-RI.

Spontaneous Non-Aneurysmal Convexity Subarachnoid Hemorrhage: A Scoping Review of Different Etiologies beyond Cerebral Amyloid Angiopathy.

Spontaneous convexity subarachnoid hemorrhage (cSAH) is a vascular disease different from aneurysmal SAH in neuroimaging pattern, causes, and prognosis. Several causes might be considered in individual patients, with a limited value of the patient's age for discriminating among these causes. Cerebral amyloid angiopathy (CAA) is the most prevalent cause in people > 60 years, but reversible cerebral vasoconstriction syndrome (RCVS) has to be considered in young people. CAA gained attention in the last years, but the most known manifestation of cSAH in this context is constituted by transient focal neurological episodes (TFNEs). CAA might have an inflammatory side (CAA-related inflammation), whose diagnosis is relevant due to the efficacy of immunosuppression in resolving essudation. Other causes are hemodynamic stenosis or occlusion in extracranial and intracranial arteries, infective endocarditis (with or without intracranial infectious aneurysms), primary central nervous system angiitis, cerebral venous thrombosis, and rarer diseases. The diagnostic work-up is fundamental for an etiological diagnosis and includes neuroimaging techniques, nuclear medicine techniques, and lumbar puncture. The correct diagnosis is the first step for choosing the most effective and appropriate treatment.

Cerebral Amyloid Angiopathy-Related Inflammation and Biopsy-Positive Primary Angiitis of the CNS: A Comparative Study.

Cerebral amyloid angiopathy-related inflammation (CAA-RI) and biopsy-positive primary angiitis of the CNS (BP-PACNS) have overlapping clinicoradiologic presentations. It is unknown whether clinical and radiologic features can differentiate CAA-RI from BP-PACNS and whether both diseases have different relapse rates. The objectives of this study were to compare clinicoradiologic presentations and relapse rates in patients with CAA-RI vs BP-PACNS. Patients with CAA-RI and BP-PACNS were enrolled from 2 retrospective multicenter cohorts. Patients with CAA-RI were biopsy-positive or met probable clinicoradiologic criteria. Patients with BP-PACNS had histopathologic confirmation of CNS angiitis, with no secondary etiology. A neuroradiologist read brain MRIs, blinded to the diagnosis of CAA-RI or BP-PACNS. Clinicoradiologic features were compared using univariable logistic regression models. Relapse rates were compared using a univariable Fine-Gray subdistribution hazard model, with death as a competing risk. This study enrolled 104 patients with CAA-RI (mean age 73 years, 48% female sex) and 52 patients with BP-PACNS (mean age 45 years, 48% female sex). Patients with CAA-RI more often had white matter hyperintense lesions meeting the probable CAA-RI criteria (93% vs 51%, p < 0.001), acute subarachnoid hemorrhage (15% vs 2%, p = 0.02), cortical superficial siderosis (27% vs 4%, p < 0.001), ≥1 lobar microbleed (94% vs 26%, p < 0.001), past intracerebral hemorrhage (17% vs 4%, p = 0.04), ≥21 visible centrum semiovale perivascular spaces (34% vs 4%, p < 0.01), and leptomeningeal enhancement (70% vs 27%, p < 0.001). Patients with BP-PACNS more often had headaches (56% vs 31%, p < 0.01), motor deficits (56% vs 36%, p = 0.02), and nonischemic parenchymal gadolinium enhancement (82% vs 16%, p < 0.001). The prevalence of acute ischemic lesions was 18% in CAA-RI and 22% in BP-PACNS (p = 0.57). The features with the highest specificity for CAA-RI were acute subarachnoid hemorrhage (98%), cortical superficial siderosis (96%), past intracerebral hemorrhage (96%), and ≥21 visible centrum semiovale perivascular spaces (96%). The probable CAA-RI criteria had a 71% sensitivity (95% CI 44%-90%) and 91% specificity (95% CI 79%-98%) in differentiating biopsy-positive CAA-RI from BP-PACNS. The rate of relapse in the first 2 years after remission was lower in CAA-RI than in BP-PACNS (hazard ratio 0.46, 95% CI 0.22-0.96, p = 0.04). Clinicoradiologic features differed between patients with CAA-RI and those with BP-PACNS. Specific markers for CAA-RI were hemorrhagic signs of subarachnoid involvement, past intracerebral hemorrhage, ≥21 visible centrum semiovale perivascular spaces, and the probable CAA-RI criteria. A biopsy remains necessary for diagnosis in some cases of CAA-RI. The rate of relapse in the first 2 years after disease remission was lower in CAA-RI than in BP-PACNS.

Severe cerebral amyloid angiopathy related inflammation (CAA-ri) associated with vaccination: Case report and literature review

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rapid but reversible autoimmune encephalopathy where spontaneous autoantibody reaction against amyloid beta deposited in cerebral blood vessels produces characteristic neuroinflammatory changes such as vasogenic edema and microhemorrhages on MRI. The term amyloid-related imaging abnormalities (ARIA) is sometimes used to describe these changes but are more often reserved for similar MRI signal abnormalities seen after administration of anti-amyloid immunotherapy, using treatment exposure as an antecedent. It is unclear if there is any biological basis for this dichotomized distinction. We report a case of severe CAA-ri after exposure to SARS-CoV-2 vaccine and performed a literature review of CAA-ri related to vaccination. CAA-ri precipitated by immunogenic triggers other than anti-amyloid therapy would lend support to the hypothesis that ARIA seen on MRI may represent the same disease underpinned by a shared anti-Aβ autoantibody response irrespective of etiology. A thorough history should be taken before labelling CAA-ri as spontaneous.

Transient Ischemic Attack and Cerebral Amyloid Angiopathy-Related Inflammation: Similar Presentation, Different Entities

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rare subtype of CAA characterized by a perivascular inflammatory response to amyloid deposition in the brain. The authors detail the case of a 74-year-old man with aphasia, who was diagnosed with probable CAA-ri following brain magnetic resonance imaging. Treatment recom- mendations included a 5-day course of high-dose methylprednisolone. CAA-ri may manifest with transient or permanent neurological symptoms resem- bling a transient ischemic attack or stroke, potentially leading to misdiagnosis and inadequate long-term treatment. Hence, our objective is to highlight the clinical and imaging findings of this case.

Clinical characteristics of cerebral amyloid angiopathy and risk factors of cerebral amyloid angiopathy related intracerebral hemorrhage.

There is limited understanding of the differences between cerebral amyloid angiopathy (CAA) with and without intracerebral hemorrhage (ICH). This article aimed to describe the characteristics of CAA and identify the risk factors of CAA-ICH in a multicenter cohort. Patients consecutively enrolled in the national multicenter prospective Cerebral Small Vessel Disease Cohort Study who met the Boston diagnostic criteria for CAA or CAA-related inflammation were included in this study. The demographic characteristics and clinical data were collected. The clinical and radiographic differences between CAA with and without ICH were compared to identify the risk factors for CAA-ICH. A total of 219 CAA patients were included, with an average age of 67.12 ± 9.93. Of all patients, 26.0% were CAA with ICH. Univariate analysis showed that CAA-ICH is associated with carrying more APOE ε2 allele, less lobar cerebral microbleeds (CMBs), cortical superficial siderosis (cSS), lower Fazekas scale, a tendency of gait disorder, and acute onset (P < 0.05). The generalized linear mixed model yielded statistically significant associations between CAA with ICH and carrying the APOE ε2 allele, cSS, the lower number of lobar CMBs, and the lower Fazekas scale (P < 0.05). It is meaningful to classify CAA with and without ICH, as there may be different mechanisms between the two. CAA with ICH has a susceptibility to carrying APOE ε2, cSS, and a relatively small number of CMBs. Fewer CMBs do not mean lower susceptibility to ICH in CAA. Larger prospective cohort studies are necessary to further clarify these conclusions.

Longitudinal markers of cerebral amyloid angiopathy and related inflammation in rTg-DI rats

Cerebral amyloid angiopathy (CAA) is a prevalent vascular dementia and common comorbidity of Alzheimer’s disease (AD). While it is known that vascular fibrillar amyloid β (Aβ) deposits leads to vascular deterioration and can drive parenchymal CAA related inflammation (CAA-ri), underlying mechanisms of CAA pathology remain poorly understood. Here, we conducted brain regional proteomic analysis of early and late disease stages in the rTg-DI CAA rat model to gain molecular insight to mechanisms of CAA/CAA-ri progression and identify potential brain protein markers of CAA/CAA-ri. Longitudinal brain regional proteomic analysis revealed increased differentially expressed proteins (DEP) including ANXA3, HTRA1, APOE, CST3, and CLU, shared between the cortex, hippocampus, and thalamus, at both stages of disease in rTg-DI rats. Subsequent pathway analysis indicated pathway enrichment and predicted activation of TGF-β1, which was confirmed by immunolabeling and ELISA. Further, we identified numerous CAA related DEPs associate with astrocytes (HSPB1 and MLC1) and microglia (ANXA3, SPARC, TGF-β1) not previously associated with astrocytes or microglia in other AD models, possibly indicating that they are specific to CAA-ri. Thus, the data presented here identify several potential brain protein biomarkers of CAA/CAA-ri while providing novel molecular and mechanistic insight to mechanisms of CAA and CAA-ri pathological progression and glial cell mediated responses.

Diagnostic Challenges in Cerebral Amyloid Angiopathy-related Inflammation (P8-5.010)

Diagnostic Challenges in Cerebral Amyloid Angiopathy-related Inflammation (P8-5.010)

Abstract WP286: Cerebral Amyloid Angiopathy and Risk of Seizures

Introduction: Cerebral amyloid angiopathy (CAA) is associated with multiple conditions that are known to have an elevated risk of seizures, including intracerebral hemorrhage, CAA-related inflammation, and Alzheimer’s disease. However, there are limited population-based data regarding the risk of seizures associated with clinically diagnosed CAA. Methods: We performed a retrospective cohort study using inpatient and outpatient claims from 2016 to 2018 from a nationally representative 5% sample of Medicare beneficiaries. The study exposure was a diagnosis of CAA identified using ICD-10-CM code I68.0. The primary outcome was seizure, defined using previously validated ICD-10-CM code G40.x, but excluding diagnosis codes for epileptic conditions that are unlikely to be a result of CAA. Participants with prevalent seizures were excluded. Cox proportional hazards regression was used to determine the association between CAA and seizure after adjustment for age, sex, race, and vascular risk factors. Results: Of 1,403,686 patients included during the study period, 425 (0.03%) were diagnosed with CAA. Median follow-time was 3 years (IQR, 2.4-3). The cumulative incidence rate of seizures was 6.9 (95% CI, 4.8-9.9) per 100 person-years in patients with CAA and 0.30 (95% CI, 0.29-0.30) per 100 person-years in patients without CAA. In Cox proportional hazards analysis, CAA was associated with an increased risk of seizures (HR, 12.6; 95% CI, 8.8-18.0). Conclusions: In a nationally representative cohort of Medicare beneficiaries, CAA was associated with an increased risk of seizures.

Cerebral Amyloid Angiopathy-Related Inflammation Presenting as Nontraumatic Subdural Hematoma

Cerebral Amyloid Angiopathy-Related Inflammation Presenting as Nontraumatic Subdural Hematoma

ARIA‐E, ARIA‐H, and CAA‐related inflammation: time of reconsiderations?

AbstractBackgroundEvidence from published clinical trials suggests that high‐dose of monoclonal antibodies (mAbs) are needed to significantly remove parenchymal‐deposited Aβ plaques. However, high‐dosing mAbs resulted in a 25‐35% increased risk of amyloid‐related imaging abnormalities‐edema (ARIA‐E) and ARIA‐hemorrhage (ARIA‐H) side events. Although most ARIA‐E are incidentally recognized as clinically silent during pre‐planned safety monitoring MRI scans and suggested to be managed by dose reduction or suspension, it is noticeable that half of ARIA‐E progressed to symptomatic at continued dosing and to associate with late occurrence of ARIA‐H. Of particular importance, a few of them aggravated to potentially severe brain injury or death due to fatal CAA‐related events. Increased evidence from natural history studies suggests that ARIA‐E is the iatrogenic manifestation of cerebral amyloid angiopathy‐related inflammation (CAA‐ri), a rare autoimmune encephalopathy due to raised anti‐Aß autoAbs levels in the cerebrospinal fluid (CSF).MethodNatural history study of CAA‐ri demonstrated that immunotherapy‐related ARIA‐E share several commonalities with the spontaneous occurrence of autoAbs‐related ARIA‐E, including fluid, MRI, and PET biomarker changes and the potential response to treatment outcomes.ResultThe prospective longitudinal monitoring of patients with CAA‐ri provide evidence for a regional and temporal association of ARIA‐E on MRI with focal peaks of neuroinflammation on microglial‐PET imaging. This association was strong in patients with positive CSF markers of AD (ATN positive) and comorbid CAA pathology on MRI, while it was negligible in patients with CAA disease w/o AD (ATN negative). Raised CSF concentrations of anti‐Aß autoAbs were found in all patients at (sub)acute presentation, and reduced within 5 months from the ARIA‐E index event, in parallel with evidence of radiographic resolution of ARIA‐E. At follow‐up MRI scan, the occurrence of new hemorrhagic markers (aka ARIA‐H in trials) were found only in patients with coexisting CAA and AD comorbid pathology. The MRI scales for ARIA commonly used in clinical trials only partially paralleled the clinical, biological, and MRI findings.ConclusionThis suggests that to mitigate and monitor the risk of ARIA, more sensitive, specific, cost‐effective and easy to interpret diagnostic tools and biomarkers than MRI alone will be needed for precision drug‐dose tailoring.

Clearance of interstitial fluid (ISF) and CSF (CLIC) group-part of Vascular Professional Interest Area (PIA), updates in 2022-2023. Cerebrovascular disease and the failure of elimination of Amyloid-β from the brain and retina with age and Alzheimer's disease: Opportunities for therapy.

This editorial summarizes advances from the Clearance of Interstitial Fluid and Cerebrospinal Fluid (CLIC) group, within the Vascular Professional Interest Area (PIA) of the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART). The overarching objectives of the CLIC group are to: (1) understand the age-related physiology changes that underlie impaired clearance of interstitial fluid (ISF) and cerebrospinal fluid (CSF) (CLIC); (2) understand the cellular and molecular mechanisms underlying intramural periarterial drainage (IPAD) in the brain; (3) establish novel diagnostic tests for Alzheimer's disease (AD), cerebral amyloid angiopathy (CAA), retinal amyloid vasculopathy, amyloid-related imaging abnormalities (ARIA) of spontaneous and iatrogenic CAA-related inflammation (CAA-ri), and vasomotion; and (4) establish novel therapies that facilitate IPAD to eliminate amyloid β (Aβ) from the aging brain and retina, to prevent or reduce AD and CAA pathology and ARIA side events associated with AD immunotherapy.

The prevalence of radiological cerebral amyloid angiopathy-related inflammation in patients with cerebral amyloid angiopathy

ObjectivesCerebral amyloid angiopathy (CAA) related inflammation (CAA-RI) is an autoimmune inflammatory condition occurring in patients with CAA. We aimed to determine the prevalence of radiological CAA-RI amongst patients with CAA and to describe their presenting clinical features. MethodsWe performed a retrospective review of electronic medical records across multiple centers within a single healthcare network. Patients who met radiological modified Boston 2.0 criteria for CAA and had white matter hyperintensity (WMH) were included. Scans were analyzed by a vascular neurologist and confirmed by a neuroradiologist blinded to clinical information for meeting criteria for possible or probable radiographic CAA-RI. ResultsOut of 1100 patients reviewed, 511 patients met radiological modified Boston criteria for CAA and 193 patients had WMH on MRI. A total of 55 (28.5 % of those with CAA and WMH, and 10.8 % of all CAA with or without WMH) patients had MRI brain imaging suggestive of possible or probable radiographic CAA-RI. The diagnosis of CAA-RI was reported in only 10 (18.2 %) patients initially while 20 (36.4 %) were diagnosed up to 74 months later (median 0, IQR 0-9 months). At the time of earliest probable CAA-RI findings on imaging, the most common concurrent findings were cognitive impairment (74.5 %), macro-hemorrhages (52.7 %), headache (30.9 %), seizures (14.5 %), and ischemic infarcts (14.5 %). Only 18 (32.7 %) patients were treated with immunosuppression. ConclusionsThe prevalence of radiographic CAA-RI was high, and most cases were unrecognized and untreated. Further studies are needed to assess if earlier detection and treatment of radiologic CAA-RI may halt disease progression and prevent cognitive decline in these patients.

Cerebral amyloid angiopathy-related inflammation: a rare but important cause of acute confusion on the general medical take.

Cerebral amyloid angiopathy-related inflammation: a rare but important cause of acute confusion on the general medical take.

Cerebral amyloid angiopathy–related inflammation: clinical features and treatment response in a case series

IntroductionCerebral amyloid angiopathy–related inflammation (CAA-ri) is an entity characterised by an inflammatory response to β-amyloid deposition in the walls of cerebral microvessels. MethodsWe conducted a retrospective review of a series of patients with a diagnosis of CAA-ri according to histopathological study findings or clinical-radiological diagnostic criteria. ResultsThe study included 7 patients (5 men) with a mean age of 79 years. Disease onset was acute or subacute in 6 patients. The most frequent symptoms were cognitive impairment (n = 6), behavioural alterations (n = 5), epileptic seizures (n = 5), focal neurological signs (n = 4), and headache (n = 2). Cerebrospinal fluid was abnormal in 3 patients (lymphocytic pleocytosis and high protein levels). The most frequent MRI findings were microbleeds (n = 7), subcortical white matter hyperintensities on T2-FLAIR sequences (n = 7), and leptomeningeal enhancement (n = 6). Lesions were bilateral in 3 patients and most frequently involved the parieto-occipital region (n = 5). Amyloid PET studies were performed in 2 patients, one of whom showed pathological findings. Two patients underwent brain biopsy, which confirmed diagnosis. All patients received immunosuppressive therapy. An initially favourable clinical-radiological response was observed in all cases, with 2 patients presenting radiological recurrence after treatment withdrawal, with a subsequent improvement after treatment was resumed. ConclusionsEarly diagnosis of CAA-ri is essential: early treatment has been shown to improve prognosis and reduce the risk of recurrence. Although a histopathological study is needed to confirm diagnosis, clinical-radiological criteria enable diagnosis without biopsy.

Rare forms of cerebral amyloid angiopathy: pathogenesis, biological and clinical features of CAA-ri and iCAA.

Thanks to a more widespread knowledge of the disease, and improved diagnostic techniques, the clinical spectrum of cerebral amyloid angiopathy (CAA) is now broad. Sporadic CAA, hereditary CAA, CAA-related inflammation (CAA-ri) and iatrogenic CAA (iCAA) create a clinical and radiological continuum which is intriguing and only partially discovered. Despite being relatively rare, CAA-ri, an aggressive subtype of CAA with vascular inflammation, has gained growing attention also because of the therapeutic efficacy of anti-inflammatory and immunomodulating drugs. More recently, diagnostic criteria have been proposed for an unusual variant of CAA, probably related to an iatrogenic origin (iCAA), toward which there is mounting scientific interest. These atypical forms of CAA are still poorly known, and their recognition can be challenging and deserve to be pursued in specialized referral centres. The aim of this brief review is to focus current developments in the field of rare forms of CAA, its pathogenesis as well as clinical and biological features in order to increase awareness of these rare forms.

Cerebral amyloid angiopathy-related inflammation (CAARI) and HHV-6 positivity: A case report of a treatment dilemma and a possible relationship (P1-12.003)

<h3>Objective:</h3> To examine the treatment dilemma utilizing high-dose steroids in a patient with cerebral amyloid angiopathy-related inflammation (CAARI) and HHV-6 positivity. Additionally, to question a possible relationship between HHV-6 and CAARI. <h3>Background:</h3> Cerebral amyloid angiopathy-related inflammation (CAARI) has been described as a distinct syndrome with subacute cognitive decline or seizure symptoms. Previous studies have established diagnostic criteria for this entity and proposed a treatment strategy. However, the precipitating factors behind developing CAARI in a subset of patients with CAA are unclear. We present a case of CAARI in a patient with no underlying diagnosis of dementia that was found to be positive for HHV-6 in serum and CSF and treated successfully with steroids. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> An 83-year-old woman presented with a first-time generalized tonic-clonic seizure with postictal confusion. On presentation, her systolic blood pressure was elevated at 150–170, and she was tachycardic to 160 with a temperature of 38.4. A contrasted MRI brain showed multifocal vasogenic edema, sulcal FLAIR hyperintensity, and innumerable lobar microhemorrhages. Black blood contrast MRI brain angiogram was unremarkable, with no evidence of vasculitis. At this point, the patient had clinically improved but remained slightly encephalopathic with word-finding difficulties. Continuous EEG monitoring showed diffuse background slowing. Initial CSF studies revealed an isolated mildly elevated protein of 49 and negative cytology. Therefore, based on the clinical and radiographic evidence, a decision was made to undergo five days of high-dose methylprednisolone for probable CAARI. However, days later, HHV-6 in CSF resulted positive with 249 copies/ml, and a serum sample showed 1100 copies/ml. <h3>Conclusions:</h3> The concurrence of cerebral amyloid angiopathy-related inflammation (CAARI) and HHV-6 in serum and CSF might yield a diagnostic and therapeutic challenge. However, the treatment with high-dose pulsatile steroids with taper did improve the overall clinical picture. Further studies are needed to investigate a potential correlation. <b>Disclosure:</b> Dr. Alshawa has nothing to disclose. Dr. Makkieh has nothing to disclose. Miss Alsakka has nothing to disclose. Dr. Torres-Melendez has nothing to disclose.

A Case of Progressive Left Leg Weakness and Vision Changes: Focal Inflammatory Cerebral Amyloid Angiopathy Masquerading as a Glioma (P12-5.003)

<h3>Objective:</h3> To emphasize the need to consider tumefactive focal inflammatory cerebral amyloid angiopathy (CAA) in the differential diagnosis of CNS lesions. <h3>Background:</h3> Although classically considered an etiology of cognitive impairment in the elderly, CAA represents a spectrum of disease. CAA-related inflammation (CAA-ri), a distinct CAA phenotype, is characterized by vascular inflammation from amyloid deposition. CAA-ri may rarely appear as a tumefactive lesion, mimicking CNS malignancy. We present a case of biopsy-proven focal CAA-ri initially misidentified as a glioma, with the goal of increasing awareness of this entity. <h3>Design/Methods:</h3> Not applicable <h3>Results:</h3> A 68-year-old man with Parkinson’s disease presented with progressive left lower extremity weakness, word finding difficulty and vision changes. Neurological examination revealed Parkinsonian features, left homonymous superior quadrantanopia and left leg weakness. Brain MRI revealed a non-enhancing FLAIR hyperintensity in the subcortical right parieto-occipital lobe, with numerous susceptibility-weighted foci within this area, consistent with microhemorrhages versus vascular inflammation. Flash frozen pathology was initially suggestive of glioma, prompting lesionectomy. Final pathology revealed inflammation of small and medium sized blood vessels, multinucleated giant cells and positive Congo-red staining, consistent with necrotizing vasculitis and amyloid angiopathy. Treatment with steroids was deferred following risk-benefit analysis. <h3>Conclusions:</h3> We report a unique case of tumefactive CAA-ri, a clinicopathologic variant of CAA, manifesting as a mass-like lesion with distinguishing radiographic features. Our literature review identified only three prior reports of this entity. Clinical presentation depends on lesion size, location, and presence of edema and inflammation. While our patient lacked systemic co-pathologies, uterine involvement and carpal tunnel syndrome have been reported. Management relies on vascular risk modification, and steroids or immunosuppressants for active inflammation. Our case underscores the need to recognize CAA-ri in the differential of mass-like lesions. Recognizing the spectrum of CAA-related disease is key in understanding the natural history of the disease, and potential benefit of future anti-amyloid therapies. <b>Disclosure:</b> Dr. Mohammadi has nothing to disclose. Dr. Lilian has nothing to disclose. Mr. Chen has received research support from National Institues of Health. Michelle Offit, MS has nothing to disclose. Dr. Lin has nothing to disclose. Dr. Streicher has nothing to disclose. Dr. Sabharwal has nothing to disclose.

Teaching NeuroImages: Acute convexity subarachnoid hemorrhage

Nontraumatic acute convexity subarachnoid hemorrhage (cSAH) is a common manifestation of cerebral amyloid angiopathy (CAA), but has been rarely reported in patients with CAA-related inflammation (CAA-ri).1,2