Slow-growing WNT medulloblastoma with atypical magnetic resonance imaging findings: illustrative case.

BACKGROUND: Medulloblastomas, with four molecular subgroups, are generally rapid-growing tumors with significant contrast enhancement and well-defined margins. However, each subgroup's clinical features, including disease time course and imaging characteristics, are not well defined. OBSERVATIONS: The authors describe the case of a 15-year-old female who presented with a 7-month history of impaired left-hand movement and was found to have a lesion on the dorsal side of the fourth ventricle. T2-weighted magnetic resonance imaging (MRI) at the patient's first presentation showed diffuse hyperintense signal without apparent mass, and gadolinium-enhanced T1-weighted imaging showed very slight contrast enhancement. In 1 month, her symptoms progressed, and follow-up MRI revealed an increase in the size of the lesion, showing greater diffusion restriction and contrast enhancement. She underwent gross-total resection, and pathology was consistent with classic medulloblastoma. Genetic analysis of the tumor confirmed the wingless (WNT) molecular subgroup. Adjuvant chemotherapy and proton beam therapy were performed. At the 18-month follow-up, MRI showed no recurrence of disease. LESSONS: Slow-growing medulloblastoma is very rare and not known to be associated with a specific molecular subgroup. Here, the authors report a case of slow-growing WNT medulloblastoma, indicating that slow growth may be a feature of this subgroup.

Chronological Volume Changes of the Temporal Muscle Pedicle Used for Encephalo-myo-synangiosis in Combined Revascularization for Moyamoya Disease: A Prospective Observational Study.

Although postoperative neurological events due to brain compression by the swollen temporal muscle are a rare complication, the chronological volume changes of the temporal muscle pedicle and their clinical impact have not yet been documented. This prospective observational study aimed to investigate the chronological volume changes in the temporal muscle pedicle in Moyamoya disease (MMD). Eighteen consecutive combined revascularization procedures using the temporal muscle were performed for symptomatic MMD in 2021. The postoperative pedicle volume was quantified using repeated computed tomography images on postoperative days (PODs) 0, 1, 7, 14, and 30. Postoperative neurological events with radiological evaluations and collateral development evaluated using magnetic resonance angiography obtained 6 months after surgery were studied. On average, the postoperative temporal muscle pedicle volume was most significantly increased by as much as 112% ± 9.6% on POD 7 (P < 0.001) and decreased by as little as 52% ± 21% on POD 30 (P < 0.0001) relative to POD 0. One exceptional patient (overall incidence, 5.6%) demonstrated postoperative transient neurological events due to brain compression by the swollen temporal muscle with decreased focal cerebral blood flow in the adjacent cortical area. The postoperative collateral development via direct and indirect revascularizations was confirmed in 16 (89%) and 12 (67%) hemispheres, respectively. All patients, except for one rebleeding case, showed independent outcomes at the mean latest follow-up period on 290 ± 96 days after surgery. Our observations confirmed the temporal profile of muscle pedicle volume changes after combined revascularization. Through routine attempts to avoid the unfavorable effects of temporal muscle swelling, combined revascularization can provide favorable outcomes in symptomatic MMD.

Successful Treatment of Intracranial Methotrexate-associated Lymphoproliferative Disorder without Epstein-Barr Virus Infection Using Rituximab, Methotrexate, Procarbazine, and Vincristine: A Case Report.

Methotrexate-associated lymphoproliferative disorder (MTX-LPD) occurs in patients with rheumatoid arthritis (RA) treated with methotrexate (MTX). MTX-LPD is typically associated with Epstein-Barr virus (EBV) infection and regresses with MTX discontinuation. On the other hand, EBV-negative MTX-LPDs are less common and are more likely to show partial or no regression after MTX discontinuation. There were no standard chemotherapeutic options for refractory MTX-LPD. We present a case of EBV-negative MTX-LPD in the central nervous system (CNS) that was successfully treated with rituximab, methotrexate, procarbazine, and vincristine (R-MPV), followed by reduced-dose whole-brain radiotherapy (rdWBRT), following the same treatment protocol as primary CNS lymphoma. A 59-year-old woman with RA treated with MTX presented with gradually developing staggered gait, memory deficit, and disorientation. Multiple lesions with heterogeneous contrast enhancement were discovered using brain magnetic resonance imaging. The patient was suspected of having MTX-LPD, but discontinuing MTX did not result in regression of the brain lesions. She underwent a biopsy from the left parietal lesion. The tissue was pathologically diagnosed as diffuse large B-cell lymphoma. Furthermore, pathological examination through EBV-encoded ribonucleic acid in situ hybridization demonstrated a lack of EBV infection. She was ultimately diagnosed with EBV-negative CNS MTX-LPD. We applied chemotherapy with R-MPV and rdWBRT. The patient achieved a complete response. In the case of CNS MTX-LPD without EBV infection, chemotherapy with R-MPV followed by rdWBRT may be considered.

Rescue Extracranial-Intracranial Bypass for Ischemic Stroke Secondary to Progressive Human Immunodeficiency Virus-Associated Vasculopathy.

BACKGROUND: Human immunodeficiency virus (HIV) associated vasculopathy can cause ischemic cerebral stroke; however, there is limited evidence on optimal management. Herein, we report a case of acute ischemic stroke due to progressive internal carotid artery (ICA) stenosis in an HIV-positive patient. Superficial temporal artery to middle cerebral artery (STA-MCA) bypass, in addition to the best medical treatments, prevented stroke progression. CLINICAL DESCRIPTION: A 39-year-old man with HIV infection presented with a sudden onset of aphasia and right hemiparesis. Magnetic resonance imaging revealed an ischemic lesion in the left basal ganglia and concentric thickening of the vessel wall in the terminal portion of the bilateral ICAs. Despite maximal medical treatments for HIV-associated vasculopathy and possible opportunistic infections, bilateral ICA stenoses progressed, leading to a second hemodynamic stroke event. Because tissue plasminogen activator treatment failed, we performed STA-MCA bypass. A significant improvement in neurologic symptoms and cerebral blood flow was observed after surgery. No further stroke events occurred during the continuation of medical treatments. CONCLUSION: This is the first case of STA-MCA bypass performed in a patient with recurrent ischemic stroke caused by HIV-associated vasculopathy. Although further evidence is needed, such treatment options can shed new light on the management of progressive HIV-associated vasculopathy, which is refractory to maximal medical treatment.