The Japanese Society of Neurology discusses research, education, and medical care in the field of neurology and makes recommendations to the national government. Dr. Mizusawa, the former representative director of the Japanese Society of Neurology, selected committee members and made “Recommendations for Promotion of Research for Overcoming Neurological Diseases” in 2013. After that, the Future Vision Committee was established in 2014, and these recommendations have been revised once every few years by the committee. This time, the Future Vision Committee made the latest recommendations from 2020 to 2021. In this section I, we will discuss clinical and research topics of neurology categorized by the methodology, including genetic research, translational research, nucleic acid therapies, iPS research, and nursing/welfare.

The Japanese Society of Neurology discusses research, education, and medical care in the field of neurology and makes recommendations to the national government. Dr. Mizusawa, the former representative director of the Japanese Society of Neurology, selected committee members and made “Recommendations for Promotion of Research for Overcoming Neurological Diseases” in 2013. After that, the Future Vision Committee was established in 2014, and these recommendations have been revised once every few years by the committee. This time, the Future Vision Committee made the latest recommendations from 2020 to 2021. In this section II, we will discuss clinical and research topics of neurology categorized by the diseases. In each field, the hot topic of the disease was described by the expert.

The patient was a 78-year-old man. He was transferred to the emergency room presenting with aphasia and right hemiplegia. Head CT and CT angiography demonstrated a narrow territory of early ischemic signs and occlusion of the horizontal segment of the left middle cerebral artery (MCA), respectively. Endovascular thrombectomy was performed and complete recanalization of MCA was achieved. After admission, transthoracic echocardiography revealed a cystic mass near the left coronary apex of the aortic valve, which was diagnosed as an aneurysm of the sinus of Valsalva (ASV) by contrast-enhanced chest computed tomography. Transesophageal echocardiography showed a severe smoke-like echo within ASV, despite being in sinus rhythm. Intravenous anticoagulant therapy was started, and patch closure was performed by cardiovascular surgeons on the 13th day despite of early period after stroke onset. During the operation, no thrombus was seen around the inlet of ASV. On the two days after the operation, paroxysmal atrial fibrillation was detected and anticoagulant therapy was continued. In this patient, ASV was regarded as the embolic source of cerebral embolism, and anticoagulant therapy and surgical intervention were selected in the early period after stroke onset to prevent embolism recurrence, resulting in a favorable clinical course.

A 42-year-old woman presented at our hospital with acute paraphasia and word finding difficulty. She was not paralyzed or ataxic. Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) was diagnosed based on brain MRI finding of edematous lesions in bilateral temporal lobe cortexes that did not match the vascular territory, elevated lactate and pyruvate levels in blood and cerebrospinal fluid, and the presence of a mtDNA 3243A>G mutation. From six months before her visit, she had persistent anorexia, bloating, nausea and vomiting, and weight loss to 25 kg. We diagnosed her condition as chronic intestinal pseudo-obstruction (CIPO) associated with MELAS, because a gastroenterologist had previously diagnosed her with megacolon associated with colonic dysfunction. Usually, CIPO is often associated with the chronic phase of MELAS. However, since CIPO complication from the early stage of the disease is occasionally encountered, it is necessary to include mitochondrial disease in differential diagnosis of CIPO of unknown cause.

A 61-year-old man presented with slowly progressive cognitive decline. Brain MRI revealed left frontal lobe lesions with gadolinium enhancement along pia mater. Brain biopsy was performed and histopathological findings was compatible with the diagnosis of IgG4-related disease (IgG4-RD). Serum IgG4 level was within a normal range, and no other systemic organs were suggested to be involved by clinical symptoms or laboratory findings. Intravenous methylprednisolone therapy followed by oral prednisone induction markedly improved the cognitive functions and MRI findings detected at the initial diagnosis. Our case highlights the importance of including IgG4-RD as one of the differential diagnosis when encountering the patients suffering from isolated cranial lesions even in the absence of normal serum IgG4 level.

A 72-year old woman, who had a history of psoriasis and psoriatic arthritis from age of 69, was admitted because of acute progression of dyspnea and generalized muscle weakness after initiation of ustekinumab. She had been diagnosed as having lung and eye sarcoidosis ten months before admission. Nerve conduction studies revealed multiple mononeuropathy and needle electromyography showed myogenic changes with spontaneous activities. Muscle pathology showed non-caseating epithelioid granuloma and high expression of HLA-class I in myofibers. Diagnosis of sarcoid myopathy and neuropathy aggravated by ustekinumab was made, and ustekinumab administration was discontinued, resulting in slight improvement of her respiratory and neuro-muscular symptoms, but her symptoms remained severely disabled. Treatment with oral steroids further improved her clinical symptoms and she became able to walk independently. We considered that ustekinumab inhibited IL-12 and IL-23 signaling, which caused an imbalance in Th1/Th17 differentiation and activation of Th1 cell differentiation, thereby promoting the development of sarcoid myopathy and neuropathy.

A 60-year-old man with a history of bronchial asthma and nasal polyp presented with loss of vision in the right eye. His visual loss progressed within a single day, and he presented to our hospital 5 days after the onset of the symptom. Fundoscopy showed swelling and hemorrhage of the right optic disc. Blood tests revealed increased eosinophils, C-reactive protein, and perinuclear anti-neutrophil cytoplasmic antibody. Cerebrospinal fluid was normal. Cranial MRI showed local enhancement of the right optic disc and posterior ciliary arteries. He was diagnosed with arteritic anterior ischemic optic neuropathy caused by eosinophilic granulomatosis with polyangiitis (EGPA). High dose intravenous methylprednisolone was started on presentation, but the patient showed no improvement in visual function. Although a rare complication, ischemic optic neuropathy associated with EGPA should be noted, as this is an emergent condition and requires prompt diagnosis and treatment.

A 48-year-old Japanese man who had no previous medical history received his first dose of the ChAdOx1 nCoV-19 vaccine. Ten days after the vaccine administration, he developed a headache. Laboratory results indicated throm-bocytopenia and DIC. A head CT revealed microbleeding in the left parietal lobe. Contrast-enhanced CT showed thrombus in the left transverse sinus and left sigmoid sinus. A brain MRI demonstrated venous hemorrhagic infarction and subarachnoid hemorrhages in the left parietal lobe, and whole-body enhanced CT also revealed portal vein embolism and renal infarction. He was diagnosed with thrombosis with thrombocytopenia syndrome, and was treated according to the guideline. He has been recovering with the treatments. This is the first reported case of TTS associated with the ChAdOx1 nCoV-19 vaccine in Japan.

A 79-year-old man was admitted to our hospital because of sudden onset of left ataxic hemiparesis. Brain MRI diffusion weighted images showed typical lacunar infarction on the right internal capsule. He had no risk factors of cerebrovascular disorder such as hypertension, diabetes mellitus, hyperlipidemia and arrhythmia. On admission, he had a slight fever and his laboratory data showed anemia, thrombocytopenia and elevation of CRP and LDH. Intravascular large B-cell lymphoma (IVLBCL) was suspected because the serum level of soluble IL-2 receptor was also elevated. Pathological diagnosis of IVLBCL was underwent by the skin biopsy from his senile hemangiomas. Although IVLBCL was known to demonstrate various CNS lesions, it is extremely rare to be manifested as a single lacunar infarction, and this case must be important for the differential diagnosis.