Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the central nervous system (CNS) due to John Cunningham (JC) virus reactivation most often in immunocompromised patients. The brainstem and the anterior corpus callosum are uncommon locations for white matter lesions. We present a case of PML in a 40-year-old female presenting to the emergency department for a tonic seizure with transient postictal confusion. The inpatient workup revealed low cluster of differentiation cell counts (CD3 and CD4), transaminitis, positive drug screen, and abnormal electroencephalogram (EEG). The computed tomogram (CT) of the head and magnetic resonance image (MRI or MR) of the brain showed evidence of subcortical and periventricular white matter lesions in the right hemisphere extending into the brainstem and the left frontal lobe. The hospital course consisted of supportive measures, seizure treatment along with prophylaxis, and human immunodeficiency virus (HIV) management along with prophylactic antibiotics. The patient was discharged with appropriate medications and outpatient referrals. Overall, this case describes some key points. It highlights particular imaging characteristics of PML in the setting of inadequately treated HIV. For example, white matter lesions cross the anterior corpus callosum rather than the splenium, as in the \"barbell\" sign. In addition, the lesions extend inferiorly along the ipsilateral corticospinal tract into the midbrain and pons. This could be one of the first cases to capture both of these features given the rarity of their concomitant occurrence.

BACKGROUND: Critical illness-associated cerebral microbleeds (CI-aCMBs) are emerging as significant radiographic findings in patients with hypoxic ischemic injuries. Their occurrence, particularly in the corpus callosum, warrants a closer examination due to the potential implications for neurological outcomes in critically ill patients. We aim to describe a rare case of CI-aCMBs within the corpus callosum following cardiac arrest with the goal of bolstering the scientific literature on this topic.
METHODS: A 34-year-old man with a history of polysubstance abuse was found unconscious and experienced a pulseless electrical activity (PEA) cardiac arrest after a suspected drug overdose. Post-resuscitation, the patient exhibited severe respiratory distress, acute kidney injury, and profound neurological deficits.
METHODS: Initial magnetic resonance imaging scans post-cardiac arrest showed no acute brain abnormalities. However, subsequent imaging revealed extensive cerebral microbleeds predominantly in the corpus callosum, diagnosed as CI-aCMBs. These findings were made in the absence of high signal intensity on T2-weighted images, suggesting a unique pathophysiological profile of microhemorrhages.
METHODS: The patient underwent targeted temperature management (TTM) and supportive care in the intensive care unit after cardiac arrest.
RESULTS: He was subsequently extubated and had significant recovery without any neurological deficits.
CONCLUSIONS: CI-aCMBs is a rare radiographic finding after cardiac arrest. These lesions may be confined to the corpus callosum and the long-term clinical and radiographic sequelae are still largely unknown.

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a rare disease characterized by a reversible lesion in the splenium of the corpus callosum (SCC) observed on MRI. The exact etiology of MERS is unknown, although infections and antiepileptic drugs have been reported as potential causes. Herein, we present the case of a 56-year-old male patient who experienced fever and headache for 3 days. He was referred to our hospital after symptomatic treatment by his primary care physician failed to improve his symptoms. The patient had no psychiatric symptoms or significant neurological findings. Head MRI revealed a high signal on SCC on diffusion-weighted imaging, raising the suspicion of MERS. All examinations to determine the cause of MERS were negative. The patient\'s symptoms improved with antibiotics and B complex vitamins. Upon admission, abdominal CT incidentally revealed a well-defined mass on the dorsal surface of the rectum suspected to be a tailgut cyst, warranting surgical resection. The cranial margin of the tumor was caudal to the third sacrum, and a trans-sacral approach was used for resection. The fifth sacrum and the coccyx were resected, and the tumor was resected without damaging the rectum. A histopathological examination revealed a mature teratoma without any malignancy. A follow-up CT at four months postoperatively showed no evidence of clinical recurrence of MERS. Adult-onset MERS is relatively rare, and no association with tumors has been reported. The association between encephalitis and teratomas includes ovarian teratomas, which cause anti-N-methyl-D-aspartate receptor encephalitis and paraneoplastic limbic encephalitis. Although the cause of MERS was unknown in this case, we report the coexistence of a sacral teratoma and MERS to contribute to the knowledge of the association between them.

UNASSIGNED: Corpus callosum injury is a rare type of injury that occurs after a stroke and can cause lower limb dysfunction and a decrease in activities of daily living ability. Furthermore, there are no studies that focus on the progress in rehabilitation of the lower limb dysfunction caused by infarction in the corpus callosum and the effective treatment plans for this condition. We aimed to present a report of two patients with lower limb dysfunction caused by corpus callosum infarction after a stroke and a walking training method.
UNASSIGNED: We implemented a walking training method that prioritizes bilateral symmetry and increases lateral swaying before the patients established sitting/standing balance. The plan is a rapid and effective method for improving walking dysfunction caused by corpus callosum infarction.
UNASSIGNED: Following sudden corpus callosum infarction, both patients experienced a significant reduction in lower limb motor function scores and exhibited evident gait disorders. Scale evaluations confirmed that walking training based on symmetrical and increased lateral sway for patients with lower limb motor dysfunction after corpus callosum infarction led to significant symptom improvement.
UNASSIGNED: We report two cases of sudden motor dysfunction in patients with corpus callosum infarction. Symmetrical and increased lateral sway-based walking training resulted in substantial symptom improvement, as confirmed by scale assessments.

Optic Aphasia (OA) and Associative Visual Agnosia (AVA) are neuropsychological disorders characterized by impaired naming on visual presentation. From a cognitive point of view, while stimulus identification is largely unimpaired in OA (where access to semantic knowledge is still possible), in AVA it is not. OA has been linked with right hemianopia and disconnection of the occipital right-hemisphere (RH) visual processing from the left hemisphere (LH) language areas.In this paper, we describe the case of AA, an 81-year-old housewife suffering from a deficit in naming visually presented stimuli after left occipital lesion and damage to the interhemispheric splenial pathway. AA has been tested through a set of tasks assessing different levels of visual object processing. We discuss behavioral performance as well as the pattern of lesion and disconnection in relation to a neurocognitive model adapted from Luzzatti and colleagues (1998). Despite the complexity of the neuropsychological picture, behavioral data suggest that semantic access from visual input is possible, while a lesion-based structural disconnectome investigation demonstrated the splenial involvement.Altogether, neuropsychological and neuroanatomical findings support the assumption of visuo-verbal callosal disconnection compatible with a diagnosis of OA.

Susac syndrome (SuS) presents with encephalopathy, visual disturbances, and hearing loss from immune-mediated microvascular occlusion. While acute SuS is well-described, long-term cognitive outcomes with current treatments are underknown. We assessed ten SuS patients treated in accordance with evidence-based guidelines using immunotherapies targeting humoral and cell-mediated pathways. Patients were followed for a median 3.6 years. Initially, cognition inversely correlated with corpus callosum lesions on MRI. All reported cognitive improvement; 5/10 patients had residual deficits in visual attention and executive function. Early, aggressive treatment was associated with good outcomes; extensive early corpus callosum lesions may identify patients at-risk of persistent cognitive deficits.

BACKGROUND: Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) is a clinical-radiological syndrome characterized by transient central nervous system symptoms and a reversible lesion in the splenium of the corpus callosum (SCC) on magnetic resonance (MR). We reported a case of adult-onset MERS with uncommon presentation and reviewed the existing literature.
METHODS: We described a case of adult-onset MERS with uncommon symptoms and signs and performed a systematic review of case series including more than four patients of adult-onset (> 14 years old) MERS, from January 2000 to December 2022. We summarized the clinical, laboratory, imaging and therapy data.
RESULTS: We included seven eligible studies for a total of 51 adult-onset MERS patients. Neurological manifestations were preceded by prodromal symptoms in most of the patients (88%), mainly with fever (78%). Headache was the most common symptom (50%), followed by seizures (22%) and disturbance of consciousness (22%). Inflammatory changes on cerebrospinal fluid were present in a half of patient, so defining encephalitis cases. Clinal recovery, was achieved in all patients but two with severe disturbance of consciousness who required ventilator support in the acute phase. MR showed isolated lesion in the SCC in 92% of patients, while 8% of patients showed also extracallosal lesions, all the lesions resolved or improved on follow-up imaging.
CONCLUSIONS: MERS is a form of encephalitis/encephalopathy with a broad range of central nervous system manifestation, often with mild symptoms, such as headache alone, that can lead to overlooked some cases, with an excellent prognosis in most patient.

UNASSIGNED: Intracranial lipomas are a rare clinical entity. These lesions are frequently asymptomatic and originate in the pericallosal area. As they are fat-containing lesions which are intimately attached to the surrounding structures, surgery is not recommended. In some individual reports, subtotal resection is recommended to lessen complications. There have been no previous reports of corpus callosum lipoma (CCL) associated with limited dorsal myeloschizis (LDM).
UNASSIGNED: We describe the case of a combination of CCL and bilateral choroid plexus lipoma discovered incidentally during the investigation of LDM in a 3-month-old male child. Given the asymptomatic behavior of the lipoma and the vascular elements of the pericallosal area, it was decided to monitor it regularly. Thus, the patient underwent surgery only for LDM. Histological examination confirmed the diagnosis, and postoperative follow-up 1 year after showed good evolution. To the best of our knowledge, this association has never been described in the literature.
UNASSIGNED: This case suggests a possible developmental relationship between CCL and spinal dysraphism.

Alien hand syndrome (AHS) is a rare neurological phenomenon first described by Van Vleuten over a century ago. The most widely recognized variants in literature are frontal, callosal, and posterior AHS. AHS due to the corpus callosum lesion can occur alone or as part of callosal disconnection syndrome (CDS). This report presents a unique CDS case manifesting clinical features from all three AHS variants, resulting from an extensive corpus callosum infarct. Our patient exhibited various clinical features from the three AHS variants, which include grasping, groping, and difficulty releasing objects from the hand (anterior); intermanual conflict (callosal); arm levitation, mild hemiparesis, and hemisensory loss (posterior). Additionally, the extensive disruption of the corpus callosal fibers produced neurological manifestations of CDS, such as cognitive impairment, ideomotor and constructional apraxia, behavioral disorder, and transcortical motor aphasia. We employed a range of rehabilitation interventions, such as mirror box therapy, limb restraint strategy, verbal cue training, cognitive behavioral therapy, bimanual hand training, speech and language therapy, and pharmacological treatment with clonazepam. The patient showed almost complete resolution of CDS and AHS features by nine months post-stroke Our case report highlights distinctive clinical variations of AHS and the challenging correlation between clinical manifestations and neuroanatomical substrates. Future studies are necessary to explore the intricate neural connections and the precise function of the corpus callosum. This can be achieved by combining comprehensive neuropsychological testing with diffusion tensor tractography studies. It is also essential to develop a validated tool to standardize AHS assessment. Finally, the scarcity of evidence in rehabilitation interventions necessitates further studies to address the wide knowledge gap in AHS and CDS management.

Herein, we present the case of a 21-year-old man with a history of generalized tonic seizures since the age of 4 years. These seizures occurred either spontaneously or could be provoked by auditory stimuli such as the sounds of a vacuum cleaner or an electric shaver. Despite trials with 10 different anti-seizure medications, his seizures remained refractory. Interictal electroencephalography (EEG) revealed generalized epileptiform activity, whereas ictal EEG showed a generalized attenuation pattern. Magnetic resonance imaging revealed extensive chronic infarctions, predominantly in the bilateral cerebral watershed areas. At the age of 17, the patient underwent a one-stage complete callosotomy, which only achieved remission of auditory-provoked seizures. Based on this experience and published reports, we propose that the posterior corpus callosum, particularly the isthmus and anterior splenium, may be involved in seizures caused by unexpected sound stimuli.