Effect of COVID 19 pandemic on the neurology department hospitalization with analysis of the neurological complications secondary to COVID 19 and vaccination against COVID 19.

Objective: We investigated the effect of the pandemic on neurological hospitalizations and complications associated with severe acute respiratory syndrome coronavirus 2 infection or vaccinations. Methods: We retrospectively analyzed data of patients hospitalized in our neurology division from 1 April 2019 to 31 March 2022 as the opt-out study. We classified the neurological diseases into nine subgroups, evaluated changes of neurological disease characteristics, and analyzed patients hospitalized with the complications from severe acute respiratory syndrome coronavirus 2 infection or after the coronavirus disease 2019 vaccination over three eras based on the pandemic stages: (1) pre-pandemic, (2) during the pandemic but before vaccines, and (3) during the pandemic with vaccines. Results: Overall, 1756 patients were included in the analyses. The patient characteristics significantly changed throughout the pandemic (p < 0.01). Although the number of autoimmune cases did not change throughout the pandemic (p = 0.53), that of psychological cases and that of unknown cases were significantly changed (p < 0.05, p < 0.01). There were four infectious cases and 11 cases following vaccination from 1 April 2020 to 31 March 2022. The 11 postvaccination cases involved 10 kinds of neurological diseases. Conclusions: The neurological characteristics significantly changed throughout the pandemic and there were diverse neurological complications following vaccinations.

Case report of meningoencephalitis associated with SARS-CoV-2 infection showing a decrease in idiopathic focal cerebral blood flow.

Some neurological complications are associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A 74-year-old man was diagnosed with infection by SARS-CoV-2. Eighteen days after SARS-CoV-2 infection, he developed disturbed consciousness and aseptic meningoencephalitis. An analysis of cerebrospinal flood revealed an elevated cell count (184/µL) and protein level (260 mg/dL). Cranial magnetic resonance imaging showed no abnormalities. By contrast, 123I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography showed a significant decrease in cerebral blood flow (CBF) in the left parietal and occipital lobes. He died suddenly 3 months after being transferred to a rehabilitation clinic without any clear cause of death. The SARS-CoV-2 infection can cause aseptic meningoencephalitis with a distinctive decrease in CBF pattern without magnetic resonance image abnormality or intracranial artery stenosis.

Novel method for classification of prion diseases by detecting PrPres signal patterns from formalin-fixed paraffin-embedded samples.

Prion disease is an infectious and fatal neurodegenerative disease. Western blotting (WB)-based identification of proteinase K (PK)-resistant prion protein (PrPres) is considered a definitive diagnosis of prion diseases. In this study, we aimed to detect PrPres using formalin-fixed paraffin-embedded (FFPE) specimens from cases of sporadic Creutzfeldt-Jakob disease (sCJD), Gerstmann-Sträussler-Scheinker disease (GSS), glycosylphosphatidylinositol-anchorless prion disease (GPIALP), and V180I CJD. FFPE samples were prepared after formic acid treatment to inactivate infectivity. After deparaffinization, PK digestion was performed, and the protein was extracted. In sCJD, a pronounced PrPres signal was observed, with antibodies specific for type 1 and type 2 PrPres exhibited a strong or weak signals depending on the case. Histological examination of serial sections revealed that the histological changes were compatible with the biochemical characteristics. In GSS and GPIALP, prion protein core-specific antibodies presented as PrPres bands at 8-9 kDa and smear bands, respectively. However, an antibody specific for the C-terminus presented as smears in GSS, with no PrPres detected in GPIALP. It was difficult to detect PrPres in V180I CJD. Collectively, our findings demonstrate the possibility of detecting PrPres in FFPE and classifying the prion disease types. This approach facilitates histopathological and biochemical evaluation in the same sample and is safe owing to the inactivation of infectivity. Therefore, it may be valuable for the diagnosis and research of prion diseases.

Case report of transient polymyalgia rheumatica after receiving the first dose of the BNT162b2 mRNA COVID-19 vaccine.

Messenger ribonucleic acid-based vaccines that target severe acute respiratory syndrome coronavirus 2 have shown high effectiveness. While these Coronavirus Disease 2019 vaccines have a favorable safety profile, there can be rare adverse drug reactions that should be understood. Here, we report the case of a 65-year old male who displayed polymyalgia rheumatica soon after receiving the first dose of the BNT162b2 messenger ribonucleic acid Coronavirus Disease vaccine. Symptoms such as high fever and severe general pain occurred 10 days after vaccination. After administering more than 30 mg/day prednisolone, those symptoms persisted and inflammation continued until 90 days after vaccination. However, those symptoms disappeared over time, following vaccination, and the patient finally achieved complete remission from polymyalgia rheumatica without any additional treatment.

Comparison of Prognosis and Cognitive Function of Holistic Neurological Disease: Tochigi Neurological Disease Cohort Study.

Background: While many studies focus on the prognosis of individual neurological diseases, very few comprehensively compare and analyze real-world data of these diseases. Objective: To address this gap in knowledge, in this study, we comprehensively analyzed the real-life data of patients with neurological diseases. Methods: We prospectively enrolled patients with neurological diseases at three hospitals from December 1, 2016 to September 30, 2020. Neurological diseases were classified into nine groups: Dementia, Cerebrovascular disease, Parkinson's and related, Functional, Spinocerebellar degeneration, Neuroimmune, Epilepsy, Muscle dystrophy disease, and Hypertension. Patients were followed up for three years, and their prognosis and evaluation of their cognitive function served as the endpoint. Results: A total of 426 patients were finally enrolled. Both mortality and cognitive function differed among the neurological disease categories. After 3 years, mortality was highest in the Dementia (25.5%), Parkinson's and related (21.6%), and Spinocerebellar degeneration (35.3%) groups while the cognitive function of patients in these three groups was significantly lowest. Conclusions: When the neurological diseases were holistically observed, both mortality and cognitive function of the Dementia, Parkinson's and related, and Spinocerebellar degeneration groups were significantly worse than the remaining diseases.

Impact of COVID-19 pandemic on mortality and cognitive function of dementia patients: Tochigi Dementia Cohort Study.

OBJECTIVES: The coronavirus disease 2019 pandemic significantly affected Japanese society and the health of its population. Despite this, few studies have evaluated the influence of the pandemic on patients with neurological diseases or dementia, which we assessed through the Tochigi Dementia Cohort Study. METHODS: Participants were divided into two groups. The pre-pandemic group included patients who were enrolled from December 1, 2016 to November 30, 2018, and were followed up until November 30, 2019 (i.e., before the pandemic). The post-pandemic group included patients who were enrolled from December 1, 2019 to November 30, 2021, and were followed up until November 30, 2022 (i.e., during the pandemic). We recorded their age, sex, mortality, and treatment withdrawal during the follow-up period. Furthermore, we examined their cognitive function at the baseline, and after 6 and 12 months. RESULTS: A total of 384 patients were enrolled in this study, including 199 patients in the pre-pandemic group and 185 in the post-pandemic group. The mortality of dementia patients was significantly higher in the post-pandemic group than in the pre-pandemic group" (5.3% vs. 18.5%, p < 0.05*). The cognitive function scores at 12 months were also significantly lower in the dementia patients of the post-pandemic group than in those of the pre-pandemic group (p < 0.05*). CONCLUSIONS: This longitudinal cohort study conducted in a local Japanese area revealed that mortality rate and cognitive function worsened in dementia patients during the pandemic.

Early versus Later Anticoagulation for Stroke with Atrial Fibrillation.

BACKGROUND: The effect of early as compared with later initiation of direct oral anticoagulants (DOACs) in persons with atrial fibrillation who have had an acute ischemic stroke is unclear. METHODS: We performed an investigator-initiated, open-label trial at 103 sites in 15 countries. Participants were randomly assigned in a 1:1 ratio to early anticoagulation (within 48 hours after a minor or moderate stroke or on day 6 or 7 after a major stroke) or later anticoagulation (day 3 or 4 after a minor stroke, day 6 or 7 after a moderate stroke, or day 12, 13, or 14 after a major stroke). Assessors were unaware of the trial-group assignments. The primary outcome was a composite of recurrent ischemic stroke, systemic embolism, major extracranial bleeding, symptomatic intracranial hemorrhage, or vascular death within 30 days after randomization. Secondary outcomes included the components of the composite primary outcome at 30 and 90 days. RESULTS: Of 2013 participants (37% with minor stroke, 40% with moderate stroke, and 23% with major stroke), 1006 were assigned to early anticoagulation and 1007 to later anticoagulation. A primary-outcome event occurred in 29 participants (2.9%) in the early-treatment group and 41 participants (4.1%) in the later-treatment group (risk difference, -1.18 percentage points; 95% confidence interval [CI], -2.84 to 0.47) by 30 days. Recurrent ischemic stroke occurred in 14 participants (1.4%) in the early-treatment group and 25 participants (2.5%) in the later-treatment group (odds ratio, 0.57; 95% CI, 0.29 to 1.07) by 30 days and in 18 participants (1.9%) and 30 participants (3.1%), respectively, by 90 days (odds ratio, 0.60; 95% CI, 0.33 to 1.06). Symptomatic intracranial hemorrhage occurred in 2 participants (0.2%) in both groups by 30 days. CONCLUSIONS: In this trial, the incidence of recurrent ischemic stroke, systemic embolism, major extracranial bleeding, symptomatic intracranial hemorrhage, or vascular death at 30 days was estimated to range from 2.8 percentage points lower to 0.5 percentage points higher (based on the 95% confidence interval) with early than with later use of DOACs. (Funded by the Swiss National Science Foundation and others; ELAN ClinicalTrials.gov number, NCT03148457.).

Persistent High Pulse Pressure in Acute Non-Cardiogenic Ischemic Stroke as a Predictor of Neurological Deterioration and Recurrence of Ischemic Stroke: ADS Post-Hoc Analysis.

AIM: Studies investigating the relationship between pulse pressure (PP) and prognosis in acute ischemic stroke remain limited. Thus, in this study, we aim to determine whether changes in PP in the early phase of ischemic stroke are associated with neurological deterioration or stroke recurrence. METHODS: Patients who participated in the Acute Aspirin Plus Cilostazol Dual Therapy for Non-cardiogenic Stroke Patients Within 48 Hours of Symptom Onset (ADS) trial were included in this study. We then divided the patients into four groups (low-low, low-high, high-low, high-high) according to low or high PP both on admission and 24 h after admission. The threshold PP calculated by receiver operating characteristic curve analysis of PP on admission for neurological deterioration within 14 days and recurrent ischemic stroke/transient ischemic attack (TIA) within 3 months was 69 mmHg. RESULTS: Neurological deterioration within 14 days was observed in 118 patients (10.6%), whereas recurrent ischemic stroke/TIA within 3 months was noted in 34 patients (3.2%). Among these four groups, both neurological deterioration within 14 days (odds ratio [OR] 2.09, 95% confidence interval [CI] 1.12-3.91; p=0.0209) and recurrent ischemic stroke/TIA within 3 months (OR 4.80; 95% CI 1.62-14.86; p=0.0064) were significantly more frequent in the high-high group than in the low-low group as per the results of our multivariate analysis. In addition, neurological deterioration within 14 days was significantly higher in the high-low group than that in the low-low group (OR 2.70; 95% CI 1.44-5.05; p=0.0019). CONCLUSIONS: High PP during the acute phase of ischemic stroke appears to be associated with ischemic stroke recurrence and neurological deterioration, particularly if PP is elevated both on admission and 24 h later after admission.

Improper Application of a Rivastigmine Patch to the Back of the Neck Induced Toxic Symptoms.

Rivastigmine is a highly effective drug for treating Alzheimer's disease. However, its addiction can be fatal, so proper use of this transdermal drug is needed. We herein report an 85-year-old woman with Alzheimer's disease who inappropriately placed rivastigmine patches on the back of her neck. She suffered from acute cholinergic syndrome, hypersalivation, anorexia, dyspnea, and vomiting. These symptoms disappeared when the improper use of rivastigmine patches was ceased. This case serves as a warning to physicians and pharmacists of the risk associated with the improper placement of rivastigmine patches.

Tachycardia Changes Increase Neurological Deterioration in Patients with Acute Non-Cardioembolic Stroke: An ADS Post-Hoc Analysis.

AIM: A previous randomized study showed that dual antiplatelet therapy (DAPT) with aspirin and cilostazol is not superior to aspirin monotherapy for patients with acute non-cardioembolic stroke; however, the reason for this remains uncertain. We focused on the unusual side effects of cilostazol, namely, tachycardia changes, and validated their influence on patients with acute non-cardioembolic stroke. METHODS: This post-hoc study extracted data from the acute aspirin plus cilostazol dual therapy study (ADS) registry, a multicenter, prospective, randomized, open-label trial. Patients were randomly allocated to the dual group (aspirin plus cilostazol) and the aspirin monotherapy group (aspirin alone). Tachycardia changes were defined as ≥ 5% heart rate increase at 48 h after admission compared with that at admission. Baseline data and outcomes were validated with four divided groups: aspirin-non-tachycardia changes (AN), aspirin-tachycardia changes (AT), dual-non-tachycardia changes (DN), and dual-tachycardia changes (DT). RESULTS: Finally, 1,188 patients were analyzed in this ADS post-hoc analysis (aspirin monotherapy group, 594; dual group, 594). The proportion of change in tachycardia was 19.2% in the aspirin monotherapy group and 38.2% in the dual group (p＜0.001＊＊＊). Although the recurrences of symptomatic stroke and transient ischemic attack were not significantly different, the neurological deterioration was significantly different among the AN, AT, DN, and DT groups (p＜0.05＊). CONCLUSIONS: Tachycardia changes increase neurological deterioration even in patients with non-cardioembolic acute stroke. DAPT consisting of aspirin and cilostazol increases the proportion of tachycardia changes and is not superior to aspirin monotherapy.

Spontaneous Echo Contrast in the Left Atrium and Aortic-Arch Atheroma, Detected by Transesophageal Echocardiography, Was Negatively Correlated with Cognitive Function.

BACKGROUND: The relationship between transesophageal echocardiography findings and cognitive function. OBJECTIVE: This study aimed to establish an association between transesophageal echocardiography findings and cognitive function in stroke survivors. METHODS: A single-center study was conducted between April 1, 2017 and March 31, 2022. All subjects that were included had a past history of ischemic stroke and were admitted after >21 days from onset. The participants underwent cognitive function tests including a Mini-Mental State Examination, Revised Hasegawa Dementia Scale, Frontal Assessment Battery, and transesophageal echocardiography. RESULTS: The results of 126 participants were analyzed. The cognitive function of participants with a spontaneous echo contrast (+) in the left atrium including appendage or of those with an aorta-arch plaque with a maximum thickness ≥4 mm significantly worse while neither the patent foramen ovale nor the branch extending plaque influenced cognitive function (The median cognitive scores of the spontaneous echo contrast (-) versus (+) were 26 versus 22, p < 0.01**, 26 versus 21, p < 0.001***, and 14 versus 11, p < 0.01**. Those of the aortic-arch plaque max thickness (<4 mm) versus (≥4 mm) were 26 versus 25, p < 0.05*, 27 versus 24, p < 0.05*, and 15 versus 13, p < 0.05*). CONCLUSION: Our findings show that spontaneous echo contrast in the left atrium and aortic-arch atheroma detected by transesophageal echocardiography, were negatively associated with cognitive function.

Silence of resident microglia in GPI anchorless prion disease and activation of microglia in Gerstmann-Sträussler-Scheinker disease and sporadic Creutzfeldt-Jakob disease.

GPI anchorless prion diseases (GPIALPs) show numerous coarse prion protein (PrP) deposits in the CNS but neuropil spongiform changes are mild and the incidence of dementia is low. Here, we examined differences in resident microglial phenotypes between GPIALP (D178fs25) and the other prion diseases Gerstmann-Sträussler-Scheinker (GSS) disease and sporadic Creutzfeldt-Jakob disease (sCJD) with respect to homeostasis and activation. Immunohistochemistry was performed on 2 GPIALP (D178fs25), 4 GSS (P102L), and 4 sCJD cases. Homeostatic microglia expressing TMEM119 and P2RY12 were preserved in GPIALP compared to GSS and sCJD. Microglia/macrophage activation in GSS and sCJD was associated with the extent of spongiform change. Immunoelectron microscopy revealed TMEM119 and P2RY12 in PrP plaque cores. Activated microglia/macrophages expressing HLA-DR and CD68 were predominant in GSS and sCJD whereas in GPIALP, homeostatic microglia were retained and activated microglia/macrophages were rarely observed. These data suggest that PrP deposition in GPIALP is less toxic and that microglia may be immune-tolerant to PrP deposition. This may be associated with milder tissue damage and a low incidence of dementia. Whereas microglia/macrophage activation is considered to be a reaction to tissue injury, this study shows that the degree of microglia/macrophage activity might influence the extent of tissue damage.

Real-time data on the prognosis of acute ischemic stroke patients in the Tochigi Clinical ObservatioNal registry for 1-year mortality of aCute ischEmic stRoke patieNt (T-CONCERN) study.

BACKGROUND: It is important to gauge mortality in real time following an ischemic stroke. However, there is limited in-hospital and post-discharge clinical data that focuses on the real-time prognosis of acute ischemic strokes. PURPOSE: To comprehensively analyze ischemic stroke mortality during a hospital stay and 1 year after the onset of a stroke. MATERIALS AND METHODS: Initially, 1514 consecutive acute ischemic stroke patients were admitted to our facility within 7 days after the onset of a stroke. Of these, 1116 patients who were successfully surveyed 1 year after onset were finally analyzed. Baseline, physical, laboratory, and stroke clinical data were recorded and analyzed. RESULTS: The proportion of deaths within 1 year was 14.5%, 4.9% without discharge was and 9.6% after discharge within 1 year. Cardioembolic ischemic strokes were responsible for nearly 50% of the deaths within 1 year while the remaining deaths were due to non-cardioembolic ischemic strokes. After 1 year, survival rate in the hospital decreased significantly, depending on whether the stroke was recurrent or if there was bleeding without a stroke. CONCLUSIONS: Our study reveals the real-time survival data 1 year after the onset of a stroke, in-hospital and post-discharge mortality rates, and several issues associated with the treatment of acute ischemic strokes.

Coexisting of aortic arch atheroma and atrial fibrillation for short-term recurrence and poor functional outcome in acute stroke.

BACKGROUND AND PURPOSE: Multiple embolic sources are sometimes observed simultaneously in patients with embolic stroke. The present study investigated the effects of coexisting aortic arch atheroma ≥ 4 mm thick and atrial fibrillation (AF) on short-term stroke recurrence and functional outcome. METHODS: Transesophageal echocardiography (TEE) was performed in consecutive embolic stroke patients, and 395 patients were classified into 4 groups according to the presence of aortic arch atheroma ≥ 4 mm thick and AF: AF - /ARCH - group, AF + /ARCH - group, AF - /ARCH + group, and AF + /ARCH + group. In accordance with these 4 groups, we evaluated stroke recurrence and all-cause death for 3 months after stroke onset, and also evaluated the 3-month functional outcome using the modified Rankin scale (mRS). RESULTS: Among the 128 AF patients, 39.1% also had aortic arch atheroma ≥ 4 mm thick. Of the 395 enrolled cases, the AF + /ARCH + group showed the highest frequencies of stroke recurrence and all-cause death during 3 months after onset. On multivariate analysis, stroke recurrence or all-cause death during 3 months after onset was relatively more frequent in the AF + /ARCH + group than in the AF + /ARCH - group (OR, 2.34; 95% CI, 0.82-6.69; p = 0.11), but that was not statistically significant, and poor functional outcome (mRS score 3-6) at 3 months was significantly more frequent in the AF + /ARCH + group than in the AF + /ARCH - group (OR, 2.59; 95% CI, 1.08-6.24; p = 0.0339). CONCLUSIONS: Aortic arch atheroma concomitant with AF is not rare and appears associated with increased risks of stroke recurrence and poor functional outcome.

IgG4-Related Hypertrophic Pachymeningitis with Skull Base Involvement Presenting with Isolated Glossopharyngeal and Vagus Nerve Palsy.

We herein report a 70-year-old man diagnosed with IgG4-related hypertrophic pachymeningitis with skull base involvement, who presented with isolated glossopharyngeal and vagus nerve palsy. Contrast-enhanced magnetic resonance imaging (MRI) showed enhanced dural thickening of the posterior clivus and skull base involvement. When a patient with hypertrophic pachymeningitis presents with isolated cranial neuropathy without systemic manifestations or definite MRI abnormalities, it is difficult to make a diagnosis, and the patient may be misdiagnosed. This case suggests that a detailed radiological evaluation including contrast enhancement of the skull base is very important in patients with isolated glossopharyngeal and vagus nerve palsy.

Higher incidence of cervical spinal cord compression in amyotrophic lateral sclerosis: a single-institute cohort study.

BACKGROUND: Although the relationship between amyotrophic lateral sclerosis (ALS) and cervical spondylotic myelopathy (CSM) is important, data relating to CSM complications in ALS remain lacking. PURPOSE: We aimed to investigate and validate the spinal cord conditions of ALS patients. MATERIALS AND METHODS: We recruited all patients diagnosed with ALS, Parkinson's disease (PD), or chronic inflammatory demyelinating polyneuropathy (CIDP) who were admitted to our department from April 1, 2017, to March 31, 2020. We analyzed the cervical or thoracolumbar magnetic resonance imaging (MRI) scans of these 128 patients. Data relating to spondylosis, cord compression, spinal canal diameter, spinal cord diameter, and the closest distance between the cervical spinal canal and cord were validated using MRI. RESULTS: Of the 128 patients, 52 had ALS, 48 had PD, and 28 had CIDP. The proportions of both cervical spondylosis and cervical cord compression were highest in the ALS group compared with the other patient groups (p < 0.05). The proportion of cervical spondylosis in ALS patients reached 38.3%, and that of cervical cord compression reached 53.2%. The closest distance between the cervical spinal canal and cord was also significantly smaller in ALS patients compared with CIDP patients (p < 0.05). In contrast to the cervical cord findings, there were no significant differences in the thoracolumbar cord between ALS patients and the other patient groups. CONCLUSIONS: Of the three disease groups, the proportion of CSM was highest in ALS patients. Furthermore, cervical cord conditions were significantly more crowded in the ALS patients than in the other patient groups.

Successful endovascular coiling of infectious cerebral aneurysm following Staphylococcus haemolyticus endocarditis.

Recent reports suggest that Staphylococcus haemolyticus can cause infective endocarditis (IE). However, no data are available regarding infectious intracranial aneurysm (IIA) following S. haemolyticus endocarditis. Endovascular coiling is a challenging approach for the treatment of IIA. We describe the case of a 63-year-old woman who suddenly developed aphasia and dysarthria following an acute cerebral infarction in her left insular and temporal cortex. After a total hysterectomy at the age of 39, the patient had suffered from recurrent bacterial pyomyositis in her legs. At admission, there was no evidence of cerebral aneurysm, as assessed by magnetic resonance angiography, and no vegetation, as assessed by transesophageal echocardiography (TEE), resulting in an incorrect diagnosis. However, subarachnoid hemorrhage and development of cerebral aneurysm in the left middle cerebral artery occurred within 1 week of hospitalization. Continuous positive blood culture results and a second TEE finally revealed that IE was caused by S. haemolyticus. Coil embolization of the IIA was successful on day 26 after symptom onset; after this procedure, the patient began to recover. This case demonstrates that S. haemolyticus-induced endocarditis can cause IIA. Endovascular coiling is a potentially effective approach to treat IIA.

Internal Jugular Vein Velocity and Spontaneous Echo Contrast Correlate with Alzheimer's Disease and Cognitive Function.

BACKGROUND: Many issues persist in the today's Alzheimer's disease (AD) screening and the breakthrough method is desired. OBJECTIVE: We aim to validate the association between venous reflux and AD, and to develop a new method for AD screening. METHODS: We examined spontaneous echo contrast, area, diameter, retrograde velocity, and anterograde velocity of the bilateral cervical internal jugular vein (IJV) using carotid ultrasonography. RESULTS: A total of 112 patients participated in this study, with 26 diagnosed as AD. The proportion of both or either IJV spontaneous echo contrast (+) occupied 25 of total 26 AD patients, which showed 96.2%of sensitivity and 98.5%negative predictive value. The IJV velocities also showed significant correlation with AD diagnosis, although the IJV area or diameter did not. CONCLUSION: Our results indicate that the validation of the spontaneous echo contrast or velocities of the IJV are convenient AD diagnosis screening methods and that the venous reflux disturbance correlates with AD development.

Case report of an elderly woman with atypical imaging for primary central nervous system lymphoma who needed a brain biopsy for diagnosis.

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma, but its diagnosis is challenging in some cases. A brain biopsy is the gold standard for diagnosing PCNSL, but its invasiveness can be problematic. Thus, noninvasive imaging examinations have been developed for the pre-surgical diagnosis of PCNSL, including gadolinium-enhanced magnetic resonance imaging (MRI), 123I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (123I-IMP SPECT), and positron emission tomography with 18F-fluorodeoxyglucose (18F-FDG PET). Here, we report the case of a 71-year-old woman with negative imaging findings for PCNSL, but who was diagnosed with PCNSL by a brain biopsy and histological analysis. Her imaging results were negative for gadolinium-enhanced cranial MRI, with low uptake in 123I-IMP SPECT and hypometabolism in 18F-FDG PET. However, a stereotactic brain biopsy from an abnormal lesion revealed that many round cells had infiltrated into the brain. Moreover, many infiltrating cells were positive for cluster of differentiation (CD)20 and CD79a, and proliferation marker protein Ki-67-positive cells accounted for nearly 80% of all cells. Based on these results, our final pathological diagnosis was PCNSL. The present case highlights the possibility of a PCNSL diagnosis even when all imaging-related examinations display negative results.