Publications by authors named "Marc Polivka"

Objective: Chordomas represent one of the most challenging subsets of skull base and craniovertebral junction (CVJ) tumors to treat. Despite extensive resection followed by proton-beam radiation therapy, the recurrence rate remains high, highlighting the importance of developing efficient treatment strategies. In this study, the authors present their experience in treating clival and CVJ chordomas over a 29-year period.

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The International Society for the Study of Vascular Anomalies (ISSVA) has defined four vascular lesions in the central nervous system (CNS): arteriovenous malformations, cavernous angiomas (also known as cerebral cavernous malformations), venous malformations, and telangiectasias. From a retrospective central radiological and histopathological review of 202 CNS vascular lesions, we identified three cases of unclassified vascular lesions. Interestingly, they shared the same radiological and histopathological features evoking the cavernous subtype of angioleiomyomas described in the soft tissue.

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Chordomas are rare neoplasms characterized by a high recurrence rate and a poor long-term prognosis. Considering their chemo-/radio-resistance, alternative treatment strategies are strongly required, but their development is limited by the paucity of relevant preclinical models. Mutations affecting genes of the SWI/SNF complexes are frequently found in chordomas, suggesting a potential therapeutic effect of epigenetic regulators in this pathology.

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Purpose: The long-term use of cyproterone acetate (CPA) is associated with an increased risk of developing intracranial meningiomas. CPA discontinuation most often induces a stabilization or regression of the tumor. The underlying biological mechanisms as well as the reasons why some meningiomas still grow after CPA discontinuation remain unknown.

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Aminoacyl-tRNA synthetases (aaRS) are ubiquitously expressed enzymes responsible for ligating amino acids to their cognate tRNA molecules through an aminoacylation reaction. The resulting aminoacyl-tRNA is delivered to ribosome elongation factors to participate in protein synthesis. Seryl-tRNA synthetase (SARS1) is one of the cytosolic aaRSs and catalyzes serine attachment to tRNA .

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FET:CREB fusions have been described in a variety of tumors from various phenotypes. Recently, these fusion transcripts were reported in intracranial tumors, variably named intracranial mesenchymal myxoid tumors or angiomatoid fibrous histiocytomas. Controversy remains concerning the terminology for these tumors.

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Purpose: Myxopapillary ependymoma (MPE) is the most frequent tumor affecting the medullary conus. The surgical therapeutic management is still debated and only few studies have focused on the postoperative clinical outcome of patients. This study aimed to demonstrate long-term postoperative outcome and to assess the predictive factors of recurrence as well as the clinical evolution of these patients.

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Vertebral hemangiomas are relatively frequent among tumors of the spine. Most of them are asymptomatic and the diagnosis is usually made based solely on imaging. However, although rare, some hemangiomas with atypical imaging features (aggressive hemangiomas) can pose a diagnostic challenge.

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Objective: The great heterogeneity of meningiomas is challenging and we need to distinguish relevant subgroups. Spheno-orbital osteomeningiomas (SOOM) constitute a clinically specific entity, with slow-growing benign osteo-meningiomatous tumors, which recur after surgery in one fourth of cases. Neurosurgical daily practice, supported by the literature, shows that the vast majority of patients with SOOM are women, and we explored whether their epidemiological and hormonal profiles suggest a progesterone influence.

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The diagnosis of anaplastic meningioma (AM) (WHO grade III) is based on the presence of a high mitotic index (MI) and/or overt anaplasia. Only few data exist about the reproducibility and prognostic value of overt anaplasia. Additionally, the prognostic value of H3K27me3 loss in AM has not yet been demonstrated.

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NFATc2-rearranged sarcomas (NFATc2-Sarcomas) are infrequent round cell tumors characterized by EWSR1-NFATc2 fusions and FUS-NFATc2 fusions. Although our knowledge on these neoplasms has increased recently, novel diagnostic tools and more comprehensive series are still needed. Here, we describe the features of a series of seven molecularly confirmed NFATc2-Sarcomas (EWSR1-NFATc2, n = 4; FUS-NFATc2, n = 3) and demonstrate the utility of AGGRECAN immunohistochemistry for their identification.

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Background: Tumors arising from oculomotor nerve are rare, with few cases reported in the literature. Generally, whereas schwannomas are well encapsulated tumors, neurofibromas tend to invade the entire nerve fibers. These differences influence surgical resection and neurological clinical outcome, with neurofibroma often requiring the sacrifice of the nerve.

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Purpose: Subependymal giant-cell astrocytomas (SEGAs) are low grade intraventricular tumors typically found in patients with tuberous sclerosis complex (TSC). The occurrence of SEGA in non TSC patients is very rare and from a genetic point of view these so-called solitary SEGA are thought to result either from somatic mutations in one of the TSC genes (TSC1 or TSC2) limited to the tumor, or be part of a "forme fruste" of TSC with somatic mosaicism. We report on three new cases of solitary SEGA with germline and somatic mutation analysis.

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Background: Considering that pediatric high-grade gliomas (HGGs) are biologically distinct from their adult counterparts, the objective of this study was to define the landscape of HGGs in adolescents and young adults (AYAs).

Methods: We performed a multicentric retrospective study of 112 AYAs from adult and pediatric Ile-de-France neurosurgical units, treated between 1998 and 2013 to analyze their clinicoradiological and histomolecular profiles. The inclusion criteria were age between 15 and 25 years, histopathological HGG diagnosis, available clinical data, and preoperative and follow-up MRI.

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Langerhans cell histiocytosis (LCH) is a rare condition affecting children more frequently than adults. LCH can involve any organ in the body and has a wide spectrum of clinical presentation from a single self-healing bone lesion to a multisystemic life-threatening disease. The diagnosis of LCH requires histology with compatible clinical and radiological findings.

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Cerebral amyloid angiopathy related inflammation (CAA-RI) is a rare form of CAA characterized by subacute encephalitic symptoms (cognitive decline, seizures, focal deficits) associated with extensive and confluent white matter lesions co-localizing with lobar microbleeds on brain MRI. We report two cases of unusual CAA-RI mimicking meningoencephalitis but without typical brain lesions on FLAIR and T2 sequences. These 2 cases may extend the clinical spectrum of CAA-RI by suggesting the possible occurrence of quite purely meningeal forms of CAA-RI.

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We report the case of a 30-year-old woman with histologically proven monostotic fibrous dysplasia of C2 revealed by a pathological fracture of the odontoid process. Radiological investigations showed a ground-glass mineralization of the vertebral body, a centimetric lytic area with poorly defined margins involving the inferior part of the vertebral body and inferior endplate and a fracture through an osteolytic area in the base of the odontoid process. Owing to the vertebral instability, a surgical procedure combining C0-C5 fixation and posterior bone grafting was performed.

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Background: Medulloblastomas may occur in a predisposition context, including familial adenomatosis polyposis. Medulloblastomas related to a germline pathogenic variant of adenomatous polyposis coli (APC) remain rare and poorly described. Their similarities with sporadic WNT medulloblastomas still require description.

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Genetic malformations of cortical development (MCDs), such as mild MCDs (mMCD), focal cortical dysplasia (FCD), and hemimegalencephaly (HME), are major causes of severe pediatric refractory epilepsies subjected to neurosurgery. FCD2 are characterized by neuropathological hallmarks that include enlarged dysmorphic neurons (DNs) and balloon cells (BCs). Here, we provide a comprehensive assessment of the contribution of germline and somatic variants in a large cohort of surgical MCD cases.

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Intracranial germinomas (IGs) are rare malignant germ cell tumors. The septum pellucidum (SP) is an extremely rare site of IGs. To our knowledge we report the first patient presenting with synchronous involvement of the SP and the sellar region.

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We present a case of 27-year-old female who presented for a progressive frontal swelling with ipsilateral headache. Subsequent CT scan revealed an extradural and expansile multiloculated mass with thin and strongly enhanced septations and MRI evaluation showed internal hyperintensity on T2 with no restriction of diffusion and confirmed the multiple cystic spaces with enhancing septations and rare hemorrhagic fluid-fluid levels. Surgery was performed and diagnosis of aneurysmal bone cyst was made on frozen section.

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