Intraparenchymal atypical meningioma in the posterior fossa: a case report and literature review.

Intraparenchymal meningiomas without dural attachments are extremely rare. A 32-year-old female adult was admitted to our hospital, complaining of occasional dizziness. The patient had no neurological deficits. MRI demonstrated a lesion with mild edema located in the left cerebellar parenchyma. CT revealed calcification within the mass. Gross total resection was achieved. The histopathological examination indicated that the lesion was an atypical meningioma (WHO-II). We herein report an extremely rare case of an intraparenchymal meningioma located in the left cerebellar hemisphere. The significance of the differential diagnosis of lesions in the cerebellum should be emphasized.

Atypical Intraparenchymal Meningioma with YAP1-MAML2 Fusion in a Young Adult Male: A Case Report and Mini Literature Review.

Oncogenic Yes-associated protein (YAP) 1 fusions have been recently identified in several cases of meningioma mostly involving pediatric patients. The meningiomas harboring YAP1-MAML2, which is the most frequent fusion subtype, exhibit activated YAP1 signaling and share similarities with NF2 (neurofibromatosis type 2 gene) mutant meningiomas. We reported a rare case of atypical intraparenchymal meningioma with YAP1-MAML2 fusion in a 20-year-old male. The patient presented with an episode of seizure without a medical history. MRI revealed a lesion in the right temporal lobe without extra-axial involvement. The radiological and morphological findings, however, were indistinctive from other intracranial diseases, e.g., vascular malformation and glioma. Immunohistochemical results confirmed the presence of abundant meningothelial cells in the tumor and indicated brain invasion, supporting the diagnosis of atypical intraparenchymal meningioma. Targeted RNA fusion analysis further identified a YAP1-MAML2 rearrangement in the tumor. Non-dural-based intraparenchymal meningiomas are uncommon, and the careful selection of specific tumor markers is crucial for an accurate diagnosis. Additionally, the detection of the fusion gene provides valuable insights into the oncogenic mechanism of meningioma.

A Multimodal Approach to the Treatment of Intraparenchymal Meningioma in a 7-Year-Old Boy: A Case Report.

Intraparenchymal meningiomas are very rare: only 26 cases have been diagnosed in patients younger than 20 years since 1954. They can lead to preoperative differential diagnosis mistakes due to their atypical neuroimaging appearance. A multimodal approach is thus necessary to plan a surgical procedure aiming to receive the best extent of resection while preserving the patient's functional integrity. The authors report the case of a 7-year-old boy with a history of blurred vision, left eye deviation, and weakness on the left side of his body. Magnetic resonance imaging (MRI) revealed an intra-axial, cortical, right parietal lesion without dural attachment. MR spectroscopy and perfusion study were obtained. Since the patient was 100% left-handed, functional MRI, diffusion tensor imaging, and neuropsychological evaluation were performed before the surgical procedure. Histopathological analysis revealed the mass to be an atypical meningioma (WHO grade II). Postoperative MRI indicated complete macroscopic lesion removal. The postsurgical neuropsychological profile was not different from the profile before surgery. The boy was discharged 3 days after the surgical operation without any neurological deficits.

Intraparenchymal Meningioma.

Meningiomas have been described as the most frequent extra-axial tumor in the brain. Most are benign and correspond to World Health Organization (WHO) grade I; however, there are some reports of cases that shows atypical locations, like subcortical intra-axial meningiomas. This represents a challenge in radiological diagnosis because it could be taken as a metastasis tumor or vascular malformations. The authors bring a case report of a previously healthy patient who presents a traumatic brain injury with no traumatic lesions. A computed tomography (CT) evidenced a left frontal rounded subcortical lesion surrounded by large vasogenic edema. The first diagnostic impression was a metastasis tumor. During surgery, a total resection was completed, and the appearance of the tumor was meningioma. This was later confirmed by histological analysis. The literature was reviewed in order to determine the importance of including intraparenchymal meningiomas in the differential diagnosis of intracranial lesions.

Primary Intraparenchymal Meningiomas: A Case Report and a Systematic Review.

BACKGROUND: Primary intraparenchymal meningiomas are exceedingly rare and often challenging to diagnose, given their misleading radiologic features. It is hypothesized that they arise from the cap cells of the pia mater that enter the brain via penetrating blood vessels during brain development. We systematically reviewed and analyzed previously reported features of primary intraparenchymal meningiomas in terms of radiography, presenting symptoms, and histopathology. METHODS: A literature search of the Web of Science and PubMed databases and crossed references was performed in March 2021, per PRISMA guidelines, with no restrictions regarding publication date. Data regarding demographic features, clinical, radiographic, and histopathologic characteristics were extracted. RESULTS: A total of 52 patients (including the reported case) were included in this review. The mean age was 21.1 years (range, 0.3-66 years) with a male/female ratio of 1.9:1. The most common localizations of intraparenchymal meningiomas were in the frontal (30.8%) and temporal (21.2%) lobes. Cyst formation was more readily observed and was noted in 51.4% of patients. Histopathology showed a higher incidence of World Health Organization grade II (14/52, 26.9%) and World Health Organization grade III (7/52, 13.5%) of primary intraparenchymal meningiomas. CONCLUSIONS: We present a comprehensive analysis of every reported primary intraparenchymal meningioma. Because of their rarity and capacity to mimic other more common intra-axial tumors, they represent a diagnostic challenge. This systematic review highlights the importance of paying attention to atypical intra-axial lesions, with a particular reflection on the discrepancy between clinical characteristics and imaging features.

Intraparenchymal Atypical Meningioma in Basal Ganglia Region in a Child: Case Report and Literature Review.

Intraparenchymal meningiomas without dural attachment are extremely rare, especially when they occur in basal ganglia region in child. An 8-year-old boy was admitted at our hospital, complaining of recurrent headache and vomiting for 3 months. Neurological examination showed impaired vision and mild paresis of the left extremities. Magnetic resonance imaging demonstrated a lesion located in the right basal ganglia region extending to superasellar cistern with solid, multiple cystic and necrotic components. Computed tomography revealed calcification within the mass. Due to the anterior cerebral artery involvement, a subtotal resection was achieved and postoperative radiotherapy was recommended. Histopathological examination indicated that the lesion was an atypical meningioma. The postoperative rehabilitation was uneventful. Mildly impaired vision and motor weakness of left extremities improved significantly and the patient returned to normal life after surgery. To our knowledge, intraparenchymal atypical meningioma in basal ganglia extending to superasellar cistern was never reported. The significance in differential diagnosis of lesions in basal ganglia should be emphasized.

Intraparenchymal anaplastic meningioma in a child: A rare entity.

Brain tumors are not rare in children. The common brain tumors in children are medulloblastomas and craniopharyngiomas. Intraparenchymal meningiomas are very rare. We report a case of intraparenchymal meningioma in a child who was operated with a preoperative impression of a primitive neuroectodermal tumor.