A case report of pontine glioblastoma presenting as subcutaneous metastasis in nape of neck in a child

TP53 Mutation and Extraneural Metastasis of Glioblastoma: Insights From an Institutional Experience and Comprehensive Literature Review

Extraneural metastases of glioblastoma (GBM), although rare, are becoming an increasingly recognized occurrence. Currently, the biological mechanism underlying this rare occurrence is not understood. To explore the potential genomic drivers of extraneural metastasis in GBM, we present the molecular features of 4 extraneural metastatic GBMs, along with a comprehensive review and analysis of previously reported cases that had available molecular characterization. In addition to our 4 cases, 42 patients from 35 publications are reviewed. To compare the molecular profiles between GBM cases with extraneural metastasis and the general GBM population, genomic data from GBM samples in The Cancer Genome Atlas (TCGA) database were also analyzed. We found that 64.5% (20/31) of the cases with extraneural metastasis that were tested for TP53 changes had at least 1 TP53 pathogenic variant detected in either 1 or both primary and metastatic tumors. In contrast, TP53 mutation was significantly less frequent in the unselected GBM from TCGA (22.6%, 56/248) (P=0.000). In addition, O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation was more common in unselected TCGA GBM cases (48.6%, 170/350) than in cases with extraneural metastasis (31.8%, 7/22), although not statistically significant. Although isocitrate dehydrogenase (IDH) mutation is a rare occurrence in high-grade astrocytomas, IDH-mutant grade 4 astrocytomas are at least as likely to metastasize as IDH wild-type GBMs; 3 metastatic cases definitively harbored an IDH1 (p.R132H) mutation in our analysis. Our findings not only provide potential biomarkers for earlier screening of extraneural metastasis, but could also suggest clues to understanding biological mechanisms underlying GBM metastasis, and for the development of therapeutic modalities.

Diffuse Midline Glioma With Osseous Metastases at Diagnosis: A Case Report

Extraneural metastasis is extremely rare in pediatric patients with high-grade glioma and carries a grim prognosis. Detection of metastases at initial presentation is even rarer. A 15-year-old adolescent girl presented with paraplegia, urinary retention, and a constellation of systemic symptoms. Imaging showed a fourth ventricular lesion, innumerable intradural lesions, leptomeningeal seeding throughout the neuraxis, and numerous osteoblastic lesions involving the spine, ribs, sternum, pelvis, humerus, and femurs. Pathology confirmed metastatic diffuse midline glioma, H3K27M-mutant. Our patient died 2 weeks after initial presentation. Further work is needed to develop effective treatment strategies for these high-risk patients.

Systemic dissemination of glioblastoma: literature review

INTRODUCTION

Glioblastoma (GBM) is the most frequent primary malignant tumor from the central nervous system in adults. However, the presence of systemic metastasis is an extremely rare event. The objective of this study was to review the literature, evaluating the possible biological mechanisms related to the occurrence of systemic metastasis in patients diagnosed with GBM.

RESULTS

The mechanisms that may be related to GBM systemic dissemination are the blood-brain barrier breach, often seen in GBM cases, by the tumor itself or by surgical procedures, gaining access to blood and lymphatic vessels, associated with the acquisition of mesenchymal features of invasiveness, resistance to the immune mechanisms of defense and hostile environment through quiescence.

CONCLUSIONS

Tumor cells must overcome many obstacles until the development of systemic metastasis. The physiologic mechanisms are not completely clear. Although not fully understood, the pathophysiological understanding of the mechanisms that may be associated with the systemic spread is salutary for a global understanding of the disease. In addition, this knowledge may be used as a basis for a therapy to be performed in patients diagnosed with GBM distant metastasis.