Optical genome mapping identifies a novel pediatric embryonal tumor with a ZNF532::NUTM1 fusion.

The molecular characteristics of pediatric brain tumors have not only allowed for tumor subgrouping but have led to the introduction of novel treatment options for patients with specific tumor alterations. Therefore, an accurate histologic and molecular diagnosis is critical for optimized management of all pediatric patients with brain tumors, including central nervous system embryonal tumors. We present a case where optical genome mapping identified a ZNF532::NUTM1 fusion in a patient with a unique tumor best characterized histologically as a central nervous system embryonal tumor with rhabdoid features. Additional analyses including immunohistochemistry for NUT protein, methylation array, whole genome, and RNA-sequencing was done to confirm the presence of the fusion in the tumor. This is the first description of a pediatric patient with a ZNF532::NUTM1 fusion, yet the histology of this tumor is similar to that of adult cancers with ZNF::NUTM1 fusions reported in the literature. Although rare, the distinct pathology and underlying molecular characteristics of the ZNF532::NUTM1 tumor separates this from other embryonal tumors. Therefore, screening for this or similar NUTM1 rearrangements should be considered for all patients with unclassified central nervous system tumors with rhabdoid features to ensure accurate diagnosis. Ultimately, with additional cases, we may be able to better inform therapeutic management for these patients. © 2023 The Pathological Society of Great Britain and Ireland.

Spatiotemporal distribution and age of seizure onset in a pediatric epilepsy surgery cohort with cortical dysplasia.

OBJECTIVE: Focal Cortical Dysplasias (CD) are a common etiology of refractory pediatric epilepsy and are amenable to epilepsy surgery. We investigated the association of lesion volume and location to age of seizure onset among children with CD who underwent epilepsy surgery. METHODS: A retrospective study of epilepsy surgery patients with pathologically-confirmed CD. Regions of interest (ROI) determined preoperative lesion volumes on 1.5 T and 3 T T2 and SPGR MRIs, and location in 7 distributed neural networks. Descriptive and inferential statistics were used. RESULTS: Fifty-five patients were identified: 35 girls (56.5 %). Median age of seizure onset: 19.0 months (range 0.02 months - 16.0 years). Median age of surgery: 7.8 years (range 2.89 months - 24.45 years). CD were frontal (n = 21, 38 %); temporal (n = 15, 27 %); parietal (n = 10, 18 %); occipital (n = 3, 5%); multilobar (n = 6, 11 %). Frontal FCD had seizure onset < 1-year-old (P = 0.10); temporal lobe CD seizure onset was more likely > 5-years-old (P= 0.06). Median lesion volume for CD was 23.23 cm3 (range: 1.87-591.73 cm3). Larger CD lesions were associated with earlier epilepsy (P = 0.01, r = -0.16). We did not find that lesions proximal to early maturing cortical regions were associated with earlier seizure onset. We found an association with CD location in the default mode network (DMN) and age onset < 5years old (P = 0.03). Age of seizure onset was negatively correlated with percent of CD overlapping motor cortex (P = 0.001, r =-0.794) but not with CD overlap of the visual cortex (P = 0.35). There was no effect of CD type on age of epilepsy onset. SIGNIFICANCE: Larger CD lesions are associated with earlier onset epilepsy. CD most commonly occurs within the DMN and Limbic network, and DMN is associated with seizure onset before 5-years-old. Percent of CD overlapping motor cortex correlates with earlier seizure onset. These observations may reflect patterns of brain maturation or regional differences in clinical expression of seizures.

Epidermal Growth Factor Receptor Inhibition Reverses Cellular and Transcriptomic Alterations Induced by Hypoxia in the Neonatal Piglet Brain.

Acute hypoxia (HX) causes extensive cellular damage in the developing human cerebral cortex. We found increased expression of activated-EGFR in affected cortical areas of neonates with HX and investigated its functional role in the piglet, which displays a highly evolved, gyrencephalic brain, with a human-like maturation pattern. In the piglet, HX-induced activation of EGFR and Ca2+/calmodulin kinase IV (CaMKIV) caused cell death and pathological alterations in neurons and glia. EGFR blockade inhibited CaMKIV activation, attenuated neuronal loss, increased oligodendrocyte proliferation, and reversed HX-induced astrogliosis. We performed for the first time high-throughput transcriptomic analysis of the piglet cortex to define molecular responses to HX and to uncover genes specifically involved in EGFR signaling in piglet and human brain injury. Our results indicate that specific molecular responses modulated by EGFR may be targeted as a therapeutic strategy for HX injury in the neonatal brain.

Clinicopathologic Features of Diencephalic Neuronal and Glioneuronal Tumors.

Neuronal/mixed glioneuronal tumors are central nervous system neoplasms composed of neoplastic neuronal cell components or a mixture of glial and neuronal elements. They occur in cerebral hemispheres, posterior fossa, and spinal cord. Compared with other tumors at these locations, diencephalic neuronal/glioneuronal tumors are very rare and therefore not well characterized. We hereby performed clinicopathologic evaluation on 10 neuronal/glioneuronal tumors arising from the diencephalic region. Morphologically, these tumors resemble their histologic counterparts in other locations, except that lymphocytic infiltrates and microcalcifications are more common than Rosenthal fibers or eosinophilic granular bodies. The BRAFV600 mutation rate is 75%. Given the high percentage of samples being small biopsy specimens, the subtle histologic features and molecular findings greatly aided in establishing the pathologic diagnosis in several cases. At a median follow-up of 42 months, 71% of the tumors demonstrated radiological recurrence or progression, with median progression-free survival of 18 months. Recurrence/progression is observed in tumors across different histologic subtypes, necessitating additional therapies in 56% of the cases. Despite their bland histology, diencephalic neuronal/glioneuronal tumors are not clinically indolent. Their frequent recurrences warrant a close follow-up, and the prevalent BRAF mutation makes MAPK pathway inhibition a plausible treatment option when conventional therapies fail.

Differential Expression of Wilms' Tumor Protein in Diffuse Intrinsic Pontine Glioma.

Diffuse intrinsic pontine gliomas (DIPGs) are deadly tumors comprising 10%-15% of all childhood CNS cancers. Standard treatment is considered palliative and prognosis is near universal mortality. DIPGs have been classified into genomic subtypes based on histone variants with the lysine to methionine mutation on position 27 of histone tails (K27M). Given the increasing promise of immunotherapy, there have been ongoing efforts to identify tumor-specific antigens to serve as immunologic targets. We evaluated a large cohort of CNS specimens for Wilms' tumor protein (WT1) expression. These specimens include primary pediatric CNS tumors (n = 38 midline gliomas and n = 3 non-midline gliomas; n = 23 DIPG, n = 10 low-grade gliomas, n = 8 high-grade gliomas), and DIPG primary cells. Here, we report the validation of WT1 as a tumor-associated antigen in DIPGs. We further report that WT1 expression is significantly correlated with specific oncohistone variants, with the highest expression detected in the H3.3K27M subgroup. WT1 expression was absent in all control specimens (n = 21). Western blot assays using DIPG primary cells (n = 6) showed a trend of higher WT1 expression in H3.3K27M cells when compared with H3.1 K27M cells and H3 wildtype cells. Our data are the first indication of the association between WT1 and DIPG, with specific upregulation in those harboring oncohistone H3.3K27M.

Somatic Mosaicism of IDH1 R132H Predisposes to Anaplastic Astrocytoma: A Case of Two Siblings.

Anaplastic astrocytomas are aggressive glial cancers that present poor prognosis and high recurrence. Heterozygous IDH1 R132H mutations are common in adolescent and young adult anaplastic astrocytomas. In a majority of cases, the IDH1 R132H mutation is unique to the tumor, although rare cases of anaplastic astrocytoma have been described in patients with mosaic IDH1 mutations (Ollier disease or Maffucci syndrome). Here, we present two siblings with IDH1 R132H mutant high grade astrocytomas diagnosed at 14 and 26 years of age. Analysis of IDHR132H mutations in the siblings' tumors and non-neoplastic tissues, including healthy regions of the brain, cheek cells, and primary teeth indicate mosaicism of IDHR132H. Whole exome sequencing of the tumor tissue did not reveal any other common mutations between the two siblings. This study demonstrates the first example of IDH1 R132H mosaicism, acquired during early development, that provides an alternative mechanism of cancer predisposition.

Suprasellar Epidermoid Cyst Originating from the Infundibulum: Case Report and Literature Review.

Epidermoid cysts account for a small fraction of intracranial brain tumors, most commonly found in the cerebellopontine angle and parasellar cisterns. Here we present a rare case of an epidermoid cyst located in the suprasellar region, specifically originating from the infundibulum. Only one additional case with an epidermoid cyst originating within the pituitary stalk has been previously reported in the literature. The patient in this case presented with headaches, diplopia and blurred vision without any endocrinopathy. The patient's pre-operative evaluation was significant for pseudotumor cerebri, hyponatremia, obesity, and a history of smoking; post-operative course was significant for neurogenic diabetes insipidus.

Orbital malignant meningioma: a unique presentation of a rare entity.

An elderly female with progressive proptosis was found to have an aggressive retrobulbar solid orbital mass. The mass was distinct from the optic nerve sheath and intracranial meninges, and produced concave erosion of the sphenoid wing. Operative findings demonstrated an orbital mass adherent to the dura of the superior orbital fissure. The mass did not demonstrate meningeal violation, infiltrate the superior orbital fissure, or display intracranial spread. The dura remained intact after gross total resection. Histopathology revealed a malignant meningioma with papillary and focal rhabdoid morphology and bony invasion (WHO grade III). The patient received 2500cGy of stereotactic radiotherapy in addition to gross total resection. Postoperatively, the signs and symptoms of orbital mass effect resolved (proptosis, relative afferent papillary defect, and periorbital edema) and the vision improved. There was no orbital recurrence or intracranial extension. The follow-up time was limited to eight months secondary to the patient succumbing to metastatic lung adenocarcinoma, which was demonstrated to be a separate process from the orbital meningioma. We propose the etiology of this tumor to be most consistent with an orbital malignant primary extradural meningioma - the first case reported in the literature.

Comprehensive Genomic Profiling Aids in Distinguishing Metastatic Recurrence from Second Primary Cancers.

BACKGROUND: Metastatic recurrence after treatment for locoregional cancer is a major cause of morbidity and cancer-specific mortality. Distinguishing metastatic recurrence from the development of a second primary cancer has important prognostic and therapeutic value and represents a difficult clinical scenario. Advances beyond histopathological comparison are needed. We sought to interrogate the ability of comprehensive genomic profiling (CGP) to aid in distinguishing between these clinical scenarios. MATERIALS AND METHODS: We identified three prospective cases of recurrent tumors in patients previously treated for localized cancers in which histologic analyses suggested subsequent development of a distinct second primary. Paired samples from the original primary and recurrent tumor were subjected to hybrid capture next-generation sequencing-based CGP to identify base pair substitutions, insertions, deletions, copy number alterations (CNA), and chromosomal rearrangements. Genomic profiles between paired samples were compared using previously established statistical clonality assessment software to gauge relatedness beyond global CGP similarities. RESULTS: A high degree of similarity was observed among genomic profiles from morphologically distinct primary and recurrent tumors. Genomic information suggested reclassification as recurrent metastatic disease, and patients received therapy for metastatic disease based on the molecular determination. CONCLUSIONS: Our cases demonstrate an important adjunct role for CGP technologies in separating metastatic recurrence from development of a second primary cancer. Larger series are needed to confirm our observations, but comparative CGP may be considered in patients for whom distinguishing metastatic recurrence from a second primary would alter the therapeutic approach. The Oncologist 2017;22:152-157Implications for Practice: Distinguishing a metastatic recurrence from a second primary cancer can represent a difficult clinicopathologic problem but has important prognostic and therapeutic implications. Approaches to aid histologic analysis may improve clinician and pathologist confidence in this increasingly common clinical scenario. Our series provides early support for incorporating paired comprehensive genomic profiling in clinical situations in which determination of metastatic recurrence versus a distinct second primary cancer would influence patient management.

High-grade glioma with anterior skull base erosion and intranasal extension: case report.

The authors describe the case of a large WHO Grade III anaplastic oligoastrocytoma extending through the anterior skull base and into the right nasal cavity and sinuses. Glial neoplasms are typically confined to the intracranial compartment within the brain parenchyma and rarely extend into the nasal cavity without prior surgical or radiation therapy. This 42-year-old woman presented with progressive headaches and sinus congestion. MR imaging findings revealed a large intracranial lesion with intranasal extension. Endoscopic nasal biopsy revealed pathology consistent with an infiltrating glioma. The patient subsequently underwent a combined transcranial/endonasal endoscopic approach for resection of this lesion. Pathological diagnosis revealed a WHO Grade III oligoastrocytoma. This report reviews the mechanisms of extradural glioma extension. To the authors' knowledge, it is the second report of a high-grade glioma exhibiting nasal extension without prior surgical or radiation treatment.

Human herpesvirus multiplex ddPCR detection in brain tissue from low- and high-grade astrocytoma cases and controls.

BACKGROUND: Glioblastoma (GBM) is a fatal CNS malignancy, representing 50 % of all gliomas with approximately 12-18 months survival time after initial diagnosis. Recently, the human herpesvirus cytomegalovirus (CMV) has been suggested to have an oncogenic role, yet this association remains controversial. In addition, human herpesvirus 6 (HHV-6) and Epstein-Barr virus (EBV) have also been associated with low-grade gliomas, but few studies have examined HHV-6 and EBV in glioblastomas. Droplet digital PCR (ddPCR) is a highly precise diagnostic tool that enables the absolute quantification of target DNA. This study examines the association between multiple human herpesviruses and astrocytomas. METHODS: This study analyzed 112 brain tissue specimens, including 45 glioblastoma, 12 astrocytoma grade III, 2 astrocytoma grade II, 4 astrocytoma grade I, and 49 controls. All brain tissue samples were de-identified and pathologically confirmed. Each tissue block was sectioned for DNA extraction and CMV, EBV, HHV-6A and HHV-6B, and a cellular housekeeping gene were amplified by ddPCR. RESULTS: Neither CMV nor HHV-6A were detected in any of the astrocytoma samples. However, HHV-6B (p = 0.147) and EBV (p = 0.049) had a higher positivity frequency in the GBM compared to the controls. CONCLUSION: The undetectable CMV DNA in the astrocytoma cohort does not support the observation of an increased prevalence of CMV DNA in GBM, as reported in other studies. EBV has a significantly higher positivity in the GBM cohort compared to the controls, while HHV-6B has a higher but not statistically significant positivity in the case cohort. Whether these viruses play an oncogenic role in GBM remains to be further investigated.

Malignant peripheral nerve sheath tumor at the cerebellopontine angle treated with Gamma Knife radiosurgery: case report and review of the literature.

BACKGROUND AND IMPORTANCE: Malignant peripheral nerve sheath tumor (MPNST) is a rare lesion that may arise de novo or develop from an existing benign neurofibroma. Very rarely, MPNST may develop from an existing schwannoma. Intracranial MPNST is rare, and most commonly affects thevestibulocochlear nerve. Surgery is the mainstay of treatment for these lesions, but gross total resection is often difficult given the proximity of adjacent neurovascular structures. Gamma knife radiosurgery (GKS) may represent a useful adjunct to subtotal resection or biopsy of these lesions, but its use for this tumor type has not been well defined. CLINICAL PRESENTATION: The patient, who had a long history of progressive sub-clinical hearing loss, presented with facial droop and decreased facial sensation. Imaging revealed a large left cerebellopontine angle tumor extending into the internal auditory canal. The mass was subtotally resected, and pathology revealed a malignant peripheral nerve sheath tumor. The patient underwent fractionated external beam radiotherapy two months later to the resection cavity, followed by Gamma Knife radiosurgery (GKRS) to the residual tumor. Follow up imaging eight months after GKRS revealed a substantial reduction in tumor size. The patient has remained clinically stable. CONCLUSION: GKS may be a useful adjunct to multimodality treatment for malignant tumors of the CPA, such as MPNST, after subtotal resection and/or radiotherapy. Close ongoing follow up with periodic MR imaging is essential to monitor for recurrence.