ROS1 Alterations as a Potential Driver of Gliomas in Infant, Pediatric, and Adult Patients

Gliomas harboring oncogenic ROS1 alterations are uncommon and primarily described in infants. Our goal was to characterize the clinicopathological features and molecular signatures of the full spectrum of ROS1 fusion-positive gliomas across all age groups. Through a retrospective multi-institutional collaboration, we report a collection of unpublished ROS1 fusion gliomas along with the characterization and meta-analysis of new and published cases. A cohort of 32 new and 58 published cases was divided into the following 3 age groups: 19 infants, 40 pediatric patients, and 31 adults with gliomas. Tumors in infants and adults showed uniformly high-grade morphology; however, tumors in pediatric patients exhibited diverse histologic features. The GOPC::ROS1 fusion was prevalent (61/79, 77%) across all age groups, and 10 other partner genes were identified. Adult tumors showed recurrent genomic alterations characteristic of IDH wild-type glioblastoma, including the +7/-10/CDKN2A deletion; amplification of CDK4, MDM2, and PDGFRA genes; and mutations involving TERTp, TP53, PIK3R1, PIK3CA, PTEN, and NF1 genes. Infant tumors showed few genomic alterations, whereas pediatric tumors showed moderate genomic complexity. The outcomes were significantly poorer in adult patients. Although not statistically significant, tumors in infant and pediatric patients with high-grade histology and in hemispheric locations appeared more aggressive than tumors with lower grade histology or those in nonhemispheric locations. In conclusion, this study is the largest to date to characterize the clinicopathological and molecular signatures of ROS1 fusion-positive gliomas from infant, pediatric, and adult patients. We conclude that ROS1 likely acts as a driver in infant and pediatric gliomas and as a driver or codriver in adult gliomas. Integrated comprehensive clinical testing might be helpful in identifying such patients for possible targeted therapy.

Oropharyngeal Teratoma: Five-Month-Old Presenting With Failure to Thrive and Severe Obstructive Sleep Apnea

Oropharyngeal teratomas are an extremely rare congenital tumor. They are often diagnosed prenatally and can cause significant airway obstruction and feeding difficulties at birth. We present a five-month-old female that was diagnosed with a palatal teratoma that presented with failure to thrive, difficulty feeding, and eventually with severe obstructive sleep apnea. We present a five-month-old term, otherwise healthy female who became stridulous after an episode of the respiratory syncytial virus at one month old. At three months old, an otolaryngologist diagnosed mild laryngomalacia with no mass identified, and no surgical intervention was recommended. Due to continued poor weight gain, at four months old, a nasogastric tube was placed. She was subsequently admitted for further workup. She had severe stridor, a failure to thrive, and was in the 0.07th percentile for weight. Workup revealed severe obstructive sleep apnea and a palatal mass obstructing her left oropharynx. A biopsy and debulking of the mass was performed in the operating room. Pathology resulted as a mature teratoma with evidence of glial and intestinal tissue. There are no pathognomonic characteristics found on imaging to diagnose teratomas, and diagnosis is made with pathologic identification of two of the three germ cell layers. Although most teratomas are benign, there is potential for malignant transformation involving any of the represented germ cell layers. Many teratomas are diagnosed prenatally and can be quite large, often requiring Ex Utero Intrapartum Treatment (EXIT) procedure at birth to establish a safe airway. Overall, this case highlights the importance of a thorough head and neck exam, including a bilateral flexible laryngoscopy, when evaluating an infant with airway obstruction. Providers evaluating these patients should consider oropharyngeal masses, such as teratoma, as part of the differential to ensure accurate and timely diagnosis.

CSIG-09. THERAPEUTIC TARGETING OF PRENATAL PONTINE ID1 SIGNALING IN DIFFUSE MIDLINE GLIOMA

Diffuse midline gliomas (DMG) are highly invasive brain tumors with rare survival beyond two years past diagnosis. The mechanism behind tumor invasion is currently not well understood. Previous reports demonstrate upregulation of the protein ID1 with H3K27M and ACVR1 mutations in DMG, but this has not been confirmed in human tumors or therapeutically targeted. Whole exome, RNA, and ChIP-sequencing were performed on the ID1 locus in DMG tissue. Scratch-assay migration and transwell invasion assays of cultured cells were performed following shRNA-mediated ID1-knockdown. In vitro and in vivo genetic and pharmacologic [cannabidiol (CBD)] inhibition of ID1 on DMG tumor growth was assessed. Additional in vitro experiments were performed to determine a potential mechanism of action for CBD-mediated effects. Self-reported CBD dosing information was collected from DMG patients. We found that increased ID1 expression in human DMG and in utero electroporation (IUE) murine tumors is associated with H3K27M mutation and brainstem location. ChIP-sequencing indicates a similar epigenetically active state at ID1 regulatory regions in human H3K27M-DMG tumors and prenatal pontine cells. Higher ID1-expressing astrocyte-like DMG cells share a transcriptional program with oligo/astrocyte-precursor cells (OAPCs) from the developing human brain and demonstrate upregulation of the migration regulatory protein SPARCL1. Genetic and pharmacologic (CBD) suppression of ID1 decreases tumor cell migration, tumor growth, and to a lesser extent invasion in both murine IUE and multiple patient-derived in vivo DMG models, improving mouse survival. ID1 knockdown significantly decreases the effect of CBD on migration, tumor growth, and invasion. CBD increases reactive oxygen species production, which also affects DMG cell proliferation in a non-ID1 mediated manner. Overall, we find that H3K27M-mediated reactivation of ID1 in DMG results in a SPARCL1+ migratory transcriptional program that is therapeutically targetable with CBD.

Near haploidization is a genomic hallmark which defines a molecular subgroup of giant cell glioblastoma

Background

Giant cell glioblastoma (gcGBM) is a rare histologic subtype of glioblastoma characterized by numerous bizarre multinucleate giant cells and increased reticulin deposition. Compared with conventional isocitrate dehydrogenase (IDH)-wildtype glioblastomas, gcGBMs typically occur in younger patients and are generally associated with an improved prognosis. Although prior studies of gcGBMs have shown enrichment of genetic events, such as TP53 alterations, no defining aberrations have been identified. The aim of this study was to evaluate the genomic profile of gcGBMs to facilitate more accurate diagnosis and prognostication for this entity.

Methods

Through a multi-institutional collaborative effort, we characterized 10 gcGBMs by chromosome studies, single nucleotide polymorphism microarray analysis, and targeted next-generation sequencing. These tumors were subsequently compared to the genomic and epigenomic profile of glioblastomas described in The Cancer Genome Atlas (TCGA) dataset.

Results

Our analysis identified a specific pattern of genome-wide massive loss of heterozygosity (LOH) driven by near haploidization in a subset of glioblastomas with giant cell histology. We compared the genomic signature of these tumors against that of all glioblastomas in the TCGA dataset (n = 367) and confirmed that our cohort of gcGBMs demonstrated a significantly different genomic profile. Integrated genomic and histologic review of the TCGA cohort identified 3 additional gcGBMs with a near haploid genomic profile.

Conclusions

Massive LOH driven by haploidization represents a defining molecular hallmark of a subtype of gcGBM. This unusual mechanism of tumorigenesis provides a diagnostic genomic hallmark to evaluate in future cases, may explain reported differences in survival, and suggests new therapeutic vulnerabilities.

Occurrence and characterization of medulloblastoma in a patient with Curry-Jones syndrome

Medulloblastoma in a Patient with Curry-Jones Syndrome with a mosaic variant, c.1234C > T (p.Leu412Phe), in SMO.

Endobronchial Glomus Tumor in a Child

Glomus tumors (GTs) are rare, usually benign, mesenchymal neoplasms typically located in the cutaneous tissues of the extremities. Visceral locations have been reported in ∼5% of cases. The average age at diagnosis is 42 years. GTs originating in the respiratory tract of pediatric patients are exceedingly rare. We report a 16-year-old male with a GT of the right lower lobe bronchus.

YAP and the Hippo pathway in pediatric cancer

The Hippo pathway is an important signaling pathway that controls cell proliferation and apoptosis. It is evolutionarily conserved in mammals and is stimulated by cell-cell contact, inhibiting cell proliferation in response to increased cell density. During early embryonic development, the Hippo signaling pathway regulates organ development and size, and its functions result in the coordinated balance between proliferation, apoptosis, and differentiation. Its principal effectors, YAP and TAZ, regulate signaling by the embryonic stem cells and determine cell fate and histogenesis. Dysfunction of this pathway contributes to cancer development in adults and children. Emerging studies have shed light on the upregulation of Hippo pathway members in several pediatric cancers and may offer prognostic information on rhabdomyosarcoma, osteosarcoma, Wilms tumor, neuroblastoma, medulloblastoma, and other brain gliomas. We review the results of such published studies and highlight the potential clinical application of this pathway in pediatric oncologic and pathologic studies. These studies support targeting this pathway as a novel treatment strategy.

Diffusion, Perfusion, and Histopathologic Characteristics of Desmoplastic Infantile Ganglioglioma

We present a case series of a rare tumor, the desmoplastic infantile ganglioglioma (DIG) with MRI diffusion and perfusion imaging quantification as well as histopathologic characterization. Four cases with pathologically-proven DIG had diffusion weighted imaging (DWI) and two of the four had dynamic susceptibility contrast imaging. All four tumors demonstrate DWI findings compatible with low-grade pediatric tumors. For the two cases with perfusion imaging, a higher relative cerebral blood volume was associated with higher proliferation index on histopathology for one of the cases. Our results are discussed in conjunction with a literature review.

[Cervicofacial actinomycosis]

Actinomycosis is an infectious disease that appears throught the world, in cattle and human beings. It is a chronic granulomatous and suppurative lesion, usually affecting the cervicofacial area. Definitive diagnosis, by culture or biopsy, is not always possible, so the clinician must suspect it by its clinical presentation. It is the purpose of this article to present the patients diagnosed and treated in our Department during the last 5 years, and to review the ideal therapy.