Pediatric spinal cord diffuse midline glioma, H3 K27-altered with intracranial and spinal leptomeningeal spread: A case report

Primary spinal cord high-grade gliomas, including those histologically identified as glioblastoma (GBM), are a rare entity in the pediatric population but should be considered in the differential diagnosis of intramedullary lesions. Pediatric spinal cord high-grade gliomas have an aggressive course with poor prognosis. The aim of this case report is to present a 15-year-old female adolescent with histopathologically confirmed spinal cord GBM with H3F3A K27 M mutation consistent with a diffuse midline glioma (DMG), H3 K27-altered, CNS WHO grade 4 with leptomeningeal seeding on initial presentation. As imaging features of H3 K27-altered DMGs are non-specific and may mimic more frequently encountered neoplastic diseases as well as demyelinating disorders, severe neurological deficits at presentation with short duration, rapid progression, and early leptomeningeal seeding should however raise the suspicion for a pediatric-type diffuse high-grade glioma like DMG, H3 K27-altered.

BIOM-06. MOLECULAR SIGNATURES UNDERLIE THE DISTINCT FAILURE PATTERNS OF MALIGNANT GLIOMAS

BACKGROUND Malignant gliomas exhibit varied failure patterns upon recurrence; however, genomic backgrounds of these distinct phenotypes have not been evaluated. We aimed to explore the genomic traits associated with distinct failure patterns in malignant glioma patients. METHODS This study involved 272 malignant glioma patients. Failure pattern was defined for the spatial relationship between recurrent tumor and the original tumor as follows: local recurrence (LR), remote recurrence, leptomeningeal seeding (LMC), and combined failure pattern. Molecular characteristics underlying different failure patterns were investigated for the mutation profile, copy number variation (CNV), and transcriptomic signatures. RESULTS Local recurrence was the most prominent failure pattern (62.9%), followed by combined recurrence (22.8%). Multivariate Cox regression analysis confirmed failure pattern as one of the independent prognostic factors. Patients with combined failure patterns exhibited the worst prognoses, whereas patients with remote recurrence exhibited the most favorable outcomes (median overall survival = 11.4 and 25.2 months, respectively). In IDH1-wild type glioblastoma (GBM) patients, TERT and PIK3CA mutation were significantly associated with the development of combined failure pattern and leptomeningeal seeding, respectively (p-value=0.015 & p-value=0.004, respectively). Transcriptomic analysis exhibited that inter-neuronal synaptic transmission was enriched in GBMs with combined failure pattern and this finding was further validated in proteomic analysis; neuronal myelination and synaptic transmission-related pathways were upregulated in GBMs which exhibited combined failure pattern. CONCLUSIONS Collectively, we demonstrated that the inherent molecular characteristics of the tumors might contribute to the eventual relapse patterns; tracking their evolutionary pathways may unravel novel therapeutic vulnerabilities of these tumors.

Suprasellar Melanocytoma with Leptomeningeal Seeding: An Aggressive Clinical Course for a Histologically Benign Tumor

Introduction. Meningeal melanocytoma (MM) is a very rare neuroectodermal neoplasm arising from the leptomeninges. Primary suprasellar melanocytomas are exceedingly rare, with only a handful of cases reported. The systemic spread of a nontransformed meningeal melanocytoma is an unusual occurrence. Herein, we report the first case of a primary sellar melanocytoma with cerebral and spinal meningeal seeding. Case Report. A 30-year-old male with no previous medical history presented to the endocrinology department with a loss of body hair. The endocrine workup concluded with isolated hypogonadotropic hypogonadism. The Magnetic Resonance Imaging (MRI) of the brain and sella revealed a large suprasellar mass continuous with the infundibulum of the pituitary gland. It was heterogeneously hyperintense on T1-, T2-, and FLAIR-weighted images and was enhanced with contrast, along with cerebral and spinal leptomeningeal spread. The patient was referred to the neurosurgery department, and a lumbar spine biopsy was indicated. The histopathological examination was suggestive of a grade I meningeal pigmented melanocytoma. Conclusion. Thus, primary sellar melanocytomas with leptomeningeal spread are an extremely rare phenomenon. Metastatic malignant melanoma should be ruled out. Being aware of differential diagnosis and the unusual behavior of meningeal melanocytoma will be necessary to manage the patient appropriately. Complete tumor resection is the best treatment whenever possible, and radiotherapy should be considered in case of unresectability or partial resection.

Not So Benign: A Rare Atypical Ectopic Choroid Plexus Papilloma

Choroid Plexus Papillomas (CPPs) are rare neoplasms (0.4-0.6 % of all brain tumors) arising from cuboidal epithelial cells of the choroid plexus. Atypical choroid plexus papillomas are even more rare and characterized by aggressive features of increased mitotic activity and frequent metastases even at diagnosis. Atypical choroid plexus papillomas accounted for 9% of choroid plexus tumors in the Surveillance Epidemiology and End Results (SEER) Database from 1978 to 2009. We describe a 56 year-old woman with a rare atypical choroid plexus papilloma ectopically located in the cerebellopontine angle and mistaken for a vestibular schwannoma or glossopharyngeal schwannoma. She demonstrated leptomeningeal seeding involving multiple cranial nerves and spinal cord. Besides papilledema she developed several neuro-ophthalmic features slowly over time from involvement of cranial nerves and subsequent intraparenchymal spread and radiation necrosis in the brainstem. Besides being rare, the cerebellopontine angle location of this tumor is also extremely uncommon making this a very unique case.

Extraventricular Choroid Plexus Carcinoma with Spinal Metastasis: A Case Report

We report a case of extraventricular choroid plexus carcinoma (CPC) accompanied by spinal metastasis in a pediatric patient. A 15-year-old female patient presented with chronic progressive headache and blurry vision. Magnetic resonance imaging (MRI) revealed an intra-axial mass in the left frontal lobe. A gross total resection was performed, and the histopathological examination revealed the diagnosis of CPC, confirmed with immunohistochemical (IHC) analysis of GFAP, S100, EM, P53 and Ki67. Eleven months later, MRI result identified another mass in the left frontal lobe. Spinal MRI showed drop metastasis to the spine, accompanied by leptomeningeal seeding. This case demonstrated the importance of IHC and spinal MRI in the management of CPC. This case report may provide more insight into extraventricular CPC cases, which is important for the adequate management of patients with CPC in the future.

Radiologic findings and the molecular expression profile of diffuse midline glioma H3 K27M mutant

Background Diffuse midline glioma H3 K27M-mutant (DMG) are reported to show heterogeneous radiologic imaging features in children. We hypothesized that other genetic mutations may contribute to this heterogeneity. Purpose To describe the magnetic resonance imaging (MRI) findings of DMG in adult patients and to correlate the imaging findings with the molecular expression profile. Material and Methods Eighteen patients with pathologically proven DMG were enrolled. On preoperative MRI, the following were evaluated: location; size of the lesion; ratio of non-enhancing (NE) and contrast-enhancing (CE) area; presence of cortical invasion and necrotic component; maximum relative cerebral blood volume ratio (rCBV ratio) of NE and CE portions; and minimum apparent diffusion coefficient (ADC) of NE and CE portions, among others. Molecular profiles including ATRX expression and p53 mutation were reviewed to find correlation with imaging features. Results Thalamus was the most commonly involved location, followed by pons and tectum. Five patients showed loss of normal ATRX expression. p53 mutation was positive in 12 patients. 40% of normal ATRX expression patients had cortical involvement and 20% had leptomeningeal seeding; none of the patients with ATRX loss had cortical involvement or leptomeningeal seeding. Patients with normal ATRX expression showed significantly higher rCBV ratio and lower ADC value in the NE area than patients with ATRX loss ( P=0.04, 0.016). p53 mutation status did not correlate with any imaging finding. Conclusion Cortical invasion, leptomeningeal tumor spread, lower ADC value and higher rCBV ratio in NE areas of DMG may be related to normal expression of ATRX.

Evaluation of RAPNO criteria in medulloblastoma and other leptomeningeal seeding tumors using MRI and clinical data

Background Although the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group has made recommendations for response assessment in patients with medulloblastoma (MBL) and leptomeningeal seeding tumors, these criteria have yet to be evaluated. Methods We examined MR imaging and clinical data in a multicenter retrospective cohort of 269 patients with MBL diagnoses, high grade glioma, embryonal tumor, germ cell tumor, or choroid plexus papilloma. Interobserver agreement, objective response (OR) rates, and progression-free survival (PFS) were calculated. Landmark analyses were performed for OR and progression status at 0.5, 1.0, and 1.5 years after treatment initiation. Cox proportional hazards models were used to determine the associations between OR and progression with overall survival (OS). Subgroup analyses based on tumor subgroup and treatment modality were performed. Results The median follow-up time was 4.0 years. In all patients, the OR rate was .0.565 (95% CI: 0.505–0.625) by RAPNO. The interobserver agreement of OR determination between 2 raters (a neuroradiologist and a neuro-oncologist) for the RAPNO criteria in all patients was 83.8% (k statistic = 0.815; P < 0.001). At 0.5-, 1.0-, and 1.5-year landmarks, both OR status and PFS determined by RAPNO were predictive of OS (hazard ratios [HRs] for 1-year landmark: OR HR = 0.079, P < 0.001; PFS HR = 10.192, P < 0.001). In subgroup analysis, OR status and PFS were predictive of OS for all tumor subtypes and treatment modalities. Conclusion RAPNO criteria showed excellent consistency in the treatment response evaluation of MBL and other leptomeningeal seeding tumors. OR and PFS determined by RAPNO criteria correlated with OS.

Disseminated Juvenile Pilomyxoid Astrocytoma of the HypothalamicChiasmatic Region

Pilomyxoid astrocytoma (PMA) is a recently described histological type of pilocytic astrocytoma (PA), but the tumors show histological differences. PMA has more aggressive malignant behavior than PA. Magnetic Resonance Imaging (MRI) may play a crucial role in the preoperative setting and also help to establish an appropriate therapeutic regimen. In this case report, we illustrated MRI findings of a hypothalamic-chiasmatic PMA in a 15-year-old female patient presenting with extensive leptomeningeal seeding. The patient was operated for total tumor resection, but could not survive the second post-operative day. We have comprehensively discussed the clinical, imaging, and histopathological features of these relatively rare tumors and also reviewed the recent literature.