[Spontaneous Remission of Encephalitis that Developed 17 Weeks After the Last Dose of Pembrolizumab: A Case Report].

We present a 73-year-old man with a history of lung adenocarcinoma and multiple metastases. He was treated with chemotherapy, including pembrolizumab, but treatment was interrupted due to concurrent drug-induced lung injury. Seventeen weeks after the last dose of pembrolizumab, he developed encephalitis, presenting with a disturbance of consciousness and right hemiplegia. However, his symptoms gradually improved spontaneously and disappeared three weeks after their onset. Late-onset encephalitis after the administration of immune checkpoint inhibitors is rare. In addition, this is the first report of a case in which severe encephalitis recovered spontaneously without leaving sequelae. (Received April 7, 2023; Accepted July 4, 2023; Published October 1, 2023).

Motor end-plate analysis to diagnose immune-mediated myasthenia gravis in seronegative patients.

This study aimed to evaluate the diagnostic usefulness of motor end-plate (MEP) analysis along with clustered acetylcholine receptor (AChR) antibody (Ab) assays in patients with myasthenia-like symptoms but negative routine AChR and muscle-specific kinase (MuSK) Ab tests. MEP analysis of muscle biopsies of the biceps brachii was performed in 20 patients to try to differentiate between those with or without immune-mediated myasthenia gravis (MG). Using a quantitative method, complement C3 deposition and AChR densities in MEPs were examined. Independently, cell-based assays were used to detect serum clustered-AChR Abs. Only five of 20 patients had complement deposition at MEPs; four of these patients had reduced AChR densities similar to those in patients with typical AChR Ab positive MG, and distinct from those in the remaining 15 patients. Two of the four serum samples from these patients had clustered-AChR Abs. All complement-positive patients were considered as having immune-mediated MG and improved with appropriate treatments; although one patient presented with MG 3 years later, the remaining patients had other diagnoses during over 10 years of follow-up. These results suggest the usefulness of MEP analysis of muscle biopsies in diagnosing immune-mediated MG in seronegative patients with myasthenia-like symptoms but, due to the invasiveness of the muscle biopsy procedure, clustered AChR Abs should, if possible, be tested first.

A Spontaneous Extracranial Internal Carotid Artery Dissection with Autosomal Dominant Polycystic Kidney Disease: A Case Report and Literature Review.

Background and Objectives: Non-cystic manifestation of autosomal dominant polycystic kidney disease (ADPKD) is an important risk factor for cerebral aneurysms. In this report, we describe a rare spontaneous internal carotid artery (ICA) dissection in a patient with ADPKD. Observations: A 38-year-old woman with a history of ADPKD and acute myocardial infarction due to coronary artery dissection experienced severe spontaneous pain on the left side of her neck. Magnetic resonance imaging (MRI) revealed a severe left ICA stenosis localized at its origin. Carotid plaque MRI showed that the stenotic lesion was due to a subacute intramural hematoma. Close follow-up by an imaging study was performed under the diagnosis of spontaneous extracranial ICA dissection, and spontaneous regression of the intramural hematoma was observed uneventfully. Conclusions: When patients with a history of ADPKD present with severe neck pain, it is crucial to consider the possibility of a spontaneous ICA dissection. A carotid plaque MRI is beneficial in the differential diagnosis. Conservative management may benefit patients without ischemic symptoms.

Partial Clipping Occlusion Including Rupture Point Is an Effective Strategy for Ruptured Giant Fusiform Basilar Artery Aneurysm: A Technical Case Report.

Treatment of fusiform basilar artery aneurysms is still challenging today. The authors present a case of a patient with a ruptured giant fusiform basilar artery aneurysm successfully treated by clipping occlusion of the rupture point. A 62-year-old man suddenly fell into a coma due to subarachnoid hemorrhage (SAH) with a ruptured giant fusiform basilar artery aneurysm with a bleb on the right shoulder. We considered treating the lesion with stent-assisted coil embolization because of the aneurysm's shape, but we had to give up because stents were off-label in the acute phase SAH in our country. Instead, we successfully performed clipping surgery to partially occlude the aneurysm, including the rupture point via the anterior transpetrosal approach. His postoperative course was uneventful, without rerupture of the aneurysm, and his conscious level tended to improve. The postoperative imaging studies showed no complications and disappearance of the rupture point of the aneurysm. Although direct surgery for the giant fusiform basilar artery aneurysms is one of the challenging operations, it is an essential and highly effective treatment as a last resort for complex aneurysms if other treatments are not available.

Distinction in Prevalence of Atherosclerotic Embolic Sources in Cryptogenic Stroke With Cancer Status.

Background Cerebrovascular diseases are common comorbidities in patients with cancer. Although active cancer causes ischemic stroke by multiple pathological conditions, including thromboembolism attributable to Trousseau syndrome, the relationship between stroke and inactive cancer is poorly known. The aim of this study was to elucidate the different underlying pathogeneses of cryptogenic stroke in active and inactive patients with cancer, with detailed investigation by transesophageal echocardiography. Methods and Results CHALLENGE ESUS/CS (Mechanisms of Embolic Stroke Clarified by Transesophageal Echocardiography for Embolic Stroke of Undetermined Source/Cryptogenic Stroke) registry is a multicenter registry including data of patients initially diagnosed as having cryptogenic stroke and undergoing transesophageal echocardiography. Patients were divided into active cancer, inactive cancer, and noncancer groups, and their clinical features were compared. Of the total 667 enrolled patients (age, 68.7±12.8 years; 455 men), 41 (6.1%) had active cancer, and 51 (7.5%) had a history of inactive cancer. On multinomial logistic regression analysis, infarctions in multiple vascular territories (odds ratio [OR], 2.73; 95% CI, 1.39-5.40) and CRP (C-reactive protein) (OR, 1.10; 95% CI, 1.01-1.19) were independently associated with active cancer, whereas age (OR, 1.05; 95% CI, 1.01-1.08), contralateral carotid stenosis from the index stroke lesion (OR, 4.05; 95% CI, 1.60-10.27), calcification of the aortic valve (OR, 2.10; 95% CI, 1.09-4.05), and complicated lesion of the aortic arch (OR, 2.13; 95% CI, 1.11-4.10) were significantly associated with inactive cancer. Conclusions Patients with cancer were not rare in cryptogenic stroke. Although patients with active cancer had more multiple infarctions, patients with inactive cancer had more atherosclerotic embolic sources potentially causing arteriogenic strokes. Registration URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000032957.

[A case of secondary central nervous system lymphoma presenting marked hypoglycorrhachia].

A 67-year-old male was transferred to our hospital with diplopia, decreased deep tendon reflex and ataxia. He had been suspected Fisher syndrome because of previous upper respiratory tract infection. A cerebrospinal fluid examination showed marked hypoglycorrhachia, pleocytosis and elevated protein, and cytological examination suggested malignant lymphoma. Abdominal computed tomography revealed a left adrenal mass. A biopsy of the left adrenal mass revealed diffuse large B-cell lymphoma. He was treated with a combination of R-CHOP (rituximab, cyclophosphamide, doxorubicin hydrochloride, oncovin and prednisolone) and intrathecal administration of methotrexate, cytarabine and prednisolone. Neurological symptoms were gradually improved. Malignancy should be considered in addition to bacterial, fungal or tuberculous meningitis in a case with marked hypoglycorrhachia.

Right-to-left shunts may be not uncommon cause of TIA in Japan.

BACKGROUND AND PURPOSE: Although 30% to 60% of transient ischemic attacks (TIAs) have embolic sources, the etiology of the remaining TIAs is unknown. Right-to-left shunt (RLS) is one of the most important etiologies of cryptogenic stroke. The aim of this study was to determine whether RLS is related to transient ischemic attack (TIA) of unknown etiology. METHODS: We performed transesophageal echocardiography (TEE) and/or transcranial Doppler (TCD) studies for consecutive TIA patients in order to detect RLS from April 2004 to December 2006. TIA patients were divided into three groups, as follows: 1) Cardioembolic TIA, with a patent cardioembolic source, 2) thrombotic TIA, with an atherothrombotic and/or lacunar mechanism, and 3) undetermined TIA, without identified cause of TIA. We compared the characteristics and presence of RLS among these three groups. RESULTS: We enrolled 124 TIA patients (age: 67+/-13 years old, 80 men). There were 13 patients with Cardioembolic TIA, 25 with Thrombotic TIA, and 86 with Undetermined TIA. TEE and/or TCD were able to detect RLS in 61 of the 124 (49%) patients. RLS was frequent in patients with Undetermined TIA compared with those in the other TIA groups (60% in the Undetermined TIA group, 28% in the Thrombotic TIA group, and 15% in the Cardioembolic TIA group; p<0.001). Smoking and previous history of TIA were frequent in the Thrombotic TIA group (p=0.030 and p=0.016, respectively). CONCLUSION: RLS may play an important role in the etiology of TIA of undetermined cause.

A case of autoimmune thyroid disease presenting posterior reversible encephalopathy syndrome.

A 40-year-old woman was admitted to our hospital with disturbance of consciousness and seizure. We diagnosed encephalopathy associated with autoimmune thyroid disease (EAATD). Fluid-attenuated inversion recovery and diffusion-weighted MRI demonstrated hyperintense lesions in the left occipitotemporal lobe on admission, but these findings disappeared on day 11 without neurological deficits, compatible with posterior reversible encephalopathy syndrome (PRES). We report here this case of autoimmune thyroid disease presenting as PRES.