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

Spinal Diffuse Midline Glioma H3 K27M-Altered: Report of a Rare Tumor with Extracranial Skeletal Metastases and Review of Literature

Diffuse midline glioma, H3 K27-altered is a rare and aggressive pediatric brain tumor with a grim prognosis. Diffuse midline glioma is characterized by specific molecular alterations, including H3 K27 mutations, and involves deep midline structures such as the brainstem, cerebellum, spinal cord, and thalamus. These tumors present with a classic triad of symptoms and have limited surgical options due to their challenging locations. Extra-neural metastases are an unusual occurrence in diffuse midline glioma and have been rarely described. Here we report a 17-year-old girl with spinal diffuse midline glioma, H3 K27M-mutant, who presented with multiple metastatic osseous lesions confirmed on biopsy of the thoracic vertebral lesion. Due to the rapid disease progression, the patient was recommended palliative therapy. Extra-neural metastases in diffuse midline glioma are rare, with only 16 reported patients, and no standard therapy exists. An accurate and early diagnosis is necessary to develop a personalized plan of treatment. Further research is needed to gain insights into the molecular pathology of diffuse midline glioma, H3 K27-altered, and improve the quality of life and the outcome of patients with this deadly disease.

Pediatric H3K27M‑mutant diffuse midline glioma with vertebral metastasis: A case report and literature review

H3K27M-mutant diffuse midline glioma (DMG) is a type of high-grade glial tumor, which occurs in the midline structure and develops mostly in children. Extraneural metastases (ENM) are exceedingly rare in patients with H3K27M-mutant DMG. A 9-year-old male patient presented with a headache, nausea and vomiting. Following magnetic resonance imaging and immunohistochemical molecular testing examination, the patient was diagnosed with H3K27M-mutant DMG and received chemoradiotherapy plus five cycles of chemotherapy with temozolomide intermittently as an adjuvant therapy. The treatment resulted in a slight reduction of the tumor volume. However, 2 months later, the patient was admitted to hospital with complaints of drooping of the mouth, and waist and back pain. Magnetic resonance imaging and positron-emission tomography-computed tomography revealed an unusual presentation with multiple vertebral metastases and craniospinal leptomeningeal dissemination. Following discussion between the members of a multidisciplinary medical team, the patient underwent one cycle of chemotherapy with cyclophosphamide, vincristine and cisplatin. However, the condition did not improve and the patient died 4 weeks after the diagnosis of ENM. The mechanisms underlying the development of these rare metastases remain unclear. The present case report provides insights into the clinical characteristics and potential metastasis mechanisms of this aggressive disease and may help to elucidate new pathways for the management of ENM.

Extra-neural metastases in pediatric diffuse midline gliomas, H3 K27-altered: presentation of two cases and literature review

Introduction

Pediatric diffuse midline gliomas (DMG), H3 K27- altered, are the most aggressive pediatric central nervous system (CNS) malignancies. Disease outcome is dismal with a median survival of less than one year. Extra-neural metastases are an unusual occurrence in DMG and have been rarely described.

Methods and results

Here, we report on two pediatric patients affected by DMG with extra-neural dissemination. Their clinical, imaging, and molecular characteristics are reported here. An 11-year-old male 5 months after the diagnosis of diffuse intrinsic pontine glioma (DIPG) developed metastatic osseous lesions confirmed with computed tomography (CT) guided biopsy of the left iliac bone. The patient died one month after the evidence of metastatic progression. Another 11-year-old female was diagnosed with a cerebellar H3K27- altered DMG. After six months, she developed diffuse sclerotic osseous lesions. A CT-guided biopsy of the right iliac bone was non-diagnostic. She further developed multifocal chest and abdominal lymphadenopathy and pleural effusions. Droplet digital polymerase chain reaction (ddPCR) on pleural effusion revealed the presence of H3.3A mutation (c.83A>T, p.K28M). The patient died 24 months after the diagnosis of DMG and 3 months after the evidence of metastatic pleural effusion.

Discussion

Extra-neural metastasis of DMG is a rare event and no standard therapy exists. An accurate and early diagnosis is necessary in order to develop a personalized plan of treatment. Further research is needed to gain further insights into the molecular pathology of DMG, H3K27- altered and improve the quality of life and the final outcome of patients with this deadly disease.

Extraneural Metastases of Diffuse Midline Glioma, H3 K27M-Mutant at Diagnosis: Case Report, Review of the Literature, and Identifying Targetable Alterations

Extraneural metastases are rare in pediatric high-grade gliomas and little is known about the genomic profiles of tumors that disseminate beyond the central nervous system. We describe a pediatric patient with H3 K27M-mutant diffuse midline glioma of the brain and spine with biopsy-confirmed osseous metastases present at diagnosis and suspected metastatic parenchymal pulmonary disease. Several potentially clinically and/or therapeutically relevant genomic alterations were identified, including H3F3A and TP53 mutations as well as MET, CDK6, EMSY, and PIK3CG amplifications. Sequencing is critical to improve our understanding of the molecular drivers of distant metastases and discover therapeutic targets that penetrate all disease sites.

Spinal intramedullary H3K27M mutant glioma with vertebral metastasis: a case report

A new entity of gliomas, named "diffuse midline glioma (DMG), H3K27M mutant (grade IV)," which represents a specific molecular profile, was introduced to the World Health Organization (WHO) classification 2016 of central nervous system tumors. Many midline localizations have been described for this glioma, and mainly the hypothalamus, pons, thalamus, and spinal cord are sites of predilection in pediatric and young adult patients. We report the case of spinal intramedullary DMG, H3K27M mutant (WHO grade IV), that showed an unusual presentation with multiple vertebral metastases.

[Intraosseous metastasis of K27-mutant glioma]

Glioma metastasis outside the central nervous system is a quite rare phenomenon. The disease in a young woman manifested itself as back pain and loss of vision in the left eye. Magnetic resonance imaging (MRI) revealed a tumor of the optic nerve; positron emission tomography showed multiple secondary bone changes. At the same time, MRI detected no signs of neoplasm in the midline brain structures (the brain stem and subcortical nuclei) and spinal cord. Two biopsies (superior iliac spine trephine biopsy and optic nerve tumor biopsy) were performed. There were similar histological tumors; the optic nerve tumor was found to have K27M mutation in the H3F3A gene, whereas the metastatic tumor lacked this mutation (possibly due to the quality and quantity of DNA isolated from the tumor cells). The interesting features of this case are the simultaneous detection of primary and metastatic tumors before receiving any treatment and the absence of the K27M mutation in the H3F3A gene in the metastasis.