A 60-years-old previously healthy man presented with acute renal failure and hemophagocytic lymphohistiocytosis (HLH). Both conditions improved after immunotherapies, but severe limb weakness with elevation of serum CK developed. Needle EMG showed myogenic changes with spontaneous activities and muscle weakness thereafter improved without adding further immunotherapies, suggesting that our patient had viral myositis. After the stabilization of limb weakness, cecal perforation occurred due to cytomegalovirus (CMV) enteritis and temporal significant change of anti-CMV IgG antibody titer was confirmed using paired serum samples. Upregulation of MHC-class I molecule and numerous regenerative muscle fibers were observed in muscle biopsy, but no evidence of direct CMV infection in muscle fibers were seen. Although CMV infection may cause either myositis, acute renal failure, HLH or colitis in individual patient, this is the first case which had been complicated by all these conditions subsequent to CMV infection.

An 81-year-old woman admitted to our hospital due to involuntary movement on her right extremities. Laboratory tests, including autoantibodies, were unremarkable and only age related changes were observed on brain MRI. Chest CT revealed lung adenocarcinoma. She was diagnosed as having paraneoplastic chorea. After removal of the tumor, her chorea was dramatically improved. One year after the operation, abnormal high intensity lesions were seen in bilateral caudate nuclei and globus pallidus on MRI. A part of the left caudate nucleus was enhanced by gadolinium. Here we show a clinical picture and neuroradiological findings of paraneoplastic chorea associated with lung adenocarcinoma.

A 31-year old women presented with excessive startle reflex and frequent falls. Her startle reflex is induced by slight stimuli which are not problematic in most people. Soon after her startle reflex is evoked, generalized muscle stiffness occurs. She becomes rigid and falls down without loss of consciousness. Because she cannot protect herself when she is startled and falls, she has repeatedly bruised her head and face. The pedigree includes her father and two sisters with similar symptoms. Gene analysis revealed GLRA1 mutation, and she was diagnosed with hereditary hyperekplexia (HPX). Symptoms improved with clonazepam 1 mg/day. HPX patients live with severe anxiety about frequent falls and sometimes suffer serious injury, such as cerebral concussion or bone fracture. Although HPX might sometimes be underestimated, accurate diagnosis is very important for effective treatment.

A 36-year-old woman visited a local hospital suffering from acute onset dizziness. Brain MRI revealed multiple white matter lesions without gadolinium enhancement in the both hemispheres. Although she began to receive a treatment under a clinical diagnosis of multiple sclerosis, she developed newly emerging brain lesions and was referred to our hospital. Neurological examination detected intention tremor, right-sided dysdiadochokinesis, and gait ataxia. Both blood and cerebrospinal fluid tests were unremarkable but follow-up brain MRIs showed rapidly relapsing and remitting lesions. The first brain biopsy ended up showing non-specific changes but the second biopsy with five months interval confirmed primary central nervous system lymphoma (PCNSL). The patient was treated by chemotherapy and showed partial response. It is important to consider sequential brain biopsies if needed because PCNSL may present diverse brain lesions on MRI including non-neoplastic early lesions.

We report the case of a 42-year-old female with neurosarcoidosis who was hospitalized in year 2017 for gait disturbance. In 2011, she suddenly had vertigo that lasted for a few days. In 2013, she noticed left hemiplegia. A brain MRI revealed an acute infarction on the right side of the upper pons extending longitudinally from the ventral surface. In 2017, she again had left lower limb paralysis. A Brain MRI showed another infarction on the right side of the mid-pons. Hydrocephalus and brainstem atrophy were also noted. The patient was referred to our hospital. Upon neurological examination, she presented with down beat nystagmus, muscle weakness on the left side, and a broad-based spastic gait. CSF findings included an increased number of cells and protein levels with decreased glucose levels. A contrast-enhanced MRI revealed basilar meningitis causing hydrocephalus. A contrast CT scan revealed inguinal lymph node swelling, and scintigram found gallium accumulation. We diagnosed sarcoidosis via a lymph node biopsy. We speculate that chronic basilar meningitis obstructed the patient’s branching penetrating arteries inducing infarction together with obstruction of the spinal fluid flow causing hydrocephalus and cerebral atrophy.

A 68-year-old right-handed woman with acute-onset inability to stand was admitted to our department. Although left hemiparesis was minor, the neurological examination on admission showed marked body lateropulsion (BL) to the left when she stood or stepped with eyes open and feet closed. Neither ataxia nor sensory disturbance was present. Brain MRI and 3D-CT angiography revealed infarction of the right posterior cingulate and the precuneus due to dissection of the right anterior cerebral artery. BL improved on day 10 and she was discharged without sequelae on day 26. BL caused by cerebral lesions is rare, and we should recognize that infarction of the posterior cingulate and/or the precuneus can cause BL.

A previously healthy, 77-year-old woman presented with gradual cognitive decline and acute gait imbalance. On admission, despite no obvious paralysis, she tilted to the right. Her Mini-Mental State Examination score was slightly low (23/30). Gadolinium-enhanced, high-resolution T₁-weighted MRI showed abnormal arterial wall enhancement at the bilateral middle cerebral and right internal carotid arteries. The combination of arterial and parenchymal enhancement limited to the central nervous system (CNS), normal laboratory data including soluble interleukin-2 receptor, and random skin and bone-marrow biopsies was suggested of primary angiitis of the CNS (PACNS). However, a biopsy specimen from the right insula showed CD20-positive lymphoma cells indicative of diffuse large B-cell lymphoma. After receiving chemotherapy, above-mentioned abnormal findings were significantly improved. Considering the increasing clinical application of high resolution MRI, there is a risk that patients may receive a presumptive diagnosis of PACNS and immunosuppressive treatment without biopsy confirmation. It should be noted that a combination of abnormal arterial wall and linear parenchymal enhancement similar to that found for PACNS on high-resolution MRI may occur in patients with primary central nervous system lymphoma.