Extracranial Metastases From Glioblastoma With Primitive Neuronal Components on FDG PET/CT

Novel approaches to treatment of leptomeningeal metastases

PURPOSE OF REVIEW

The incidence of leptomeningeal metastases is increasing in the setting of improved survival from systemic cancers. In more recent years, our understanding of leptomeningeal metastasis pathogenesis, how to diagnose and treat has been evolving.

RECENT FINDINGS

Diagnosing leptomeningeal metastasis has been challenging due to the limitations of cytology and neuroimaging; However, newer techniques detecting circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) have shown potential advantage with diagnosis, quantification and detection of oncogenic mutations. The use of small molecule inhibitors and immunotherapy has shown some promise in specific leptomeningeal metastasis subtypes.

SUMMARY

These new discoveries have improved clinical trials' ability to assess treatment response and thereby more optimally compare different treatments. Furthermore, they have helped the individual clinician better diagnose, monitor the disease and provide novel therapies.

Glioblastoma with a primitive neuronal component: A case report

The present study describes a rare case of glioblastoma with a primitive neuronal component (GBM-PNC), and provides an in-depth analysis of the clinical, pathological and differential diagnostic findings. A comprehensive literature review was conducted to enhance the understanding of GBM-PNC, revealing its distinct characteristics and prognostic implications. A 57-year-old woman presented with acute onset headache, nausea and vomiting, leading to the identification of an intracranial mass through magnetic resonance imaging. Surgical resection revealed the coexistence of a glial component and a PNC within the tumor. Immunohistochemical analysis detected the expression of glial fibrillary acidic protein in the glial component and synaptin in the PNC. The pathological diagnosis confirmed the presence of GBM-PNC. Gene detection analysis revealed no mutations in isocitrate dehydrogenase (IDH)1 and IDH2, and neurotrophic tyrosine kinase receptor-1 (NTRK1), NTRK2 and NTRK3 genes. GBM-PNC is characterized by a propensity for recurrence and metastasis, with a low 5-year survival rate. The present case report highlights the importance of accurate diagnosis and comprehensive characterization of GBM-PNC to guide treatment decisions and improve patient outcomes.

H3G34-Mutant Gliomas-A Review of Molecular Pathogenesis and Therapeutic Options

The 2021 World Health Organization Classification of Tumors of the Central Nervous System reflected advances in understanding of the roles of oncohistones in gliomagenesis with the introduction of the H3.3-G34R/V mutant glioma to the already recognized H3-K27M altered glioma, which represent the diagnoses of pediatric-type diffuse hemispheric glioma and diffuse midline glioma, respectively. Despite advances in research regarding these disease entities, the prognosis remains poor. While many studies and clinical trials focus on H3-K27M-altered-glioma patients, those with H3.3-G34R/V mutant gliomas represent a particularly understudied population. Thus, we sought to review the current knowledge regarding the molecular mechanisms underpinning the gliomagenesis of H3.3-G34R/V mutant gliomas and the diagnosis, treatment, long-term outcomes, and possible future therapeutics.

Whole-body 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Demonstrating Multiple Rare Extracranial Metastases in a Treated Case of Glioblastoma

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults that accounts for nearly 20% of all primary malignant brain tumors. While GBM is notable for local recurrence and invasion, extracranial metastases (ECMs) are exceedingly rare, occurring in <2% of patients. However, the report of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging in evaluating ECM is limited, and the importance of whole-body FDG PET/CT imaging in GBM has not been well elucidated. We present here a case of GBM, post excision 12 years before, whole-body 18F-FDG PET/CT showing no recurrence in the brain and ECM to multiple bones, right kidney, and pancreas.

H3G34-mutant diffuse hemispheric glioma with osseous metastases: a case report and literature review

Aim: H3G34 diffuse hemispheric glioma is a CNS tumor that is difficult to diagnose and treat and accompanied with poor prognosis. It is becoming clear that extra CNS metastasis may present in a subset of patients with H3G34 gliomas, further complicating diagnosis and treatment. Materials & methods: We present a case of a 19-year-old female with a H3G34 mutant diffuse hemispheric glioma with osseous metastases. We then provide a literature review of the most recent understanding of H3G34 mutant malignancies. Conclusion: Given the stress that patients with H3G34 can experience and the poor prognosis, it is imperative to expand our knowledge and ascertain accurate diagnostic methodologies and targeted therapeutic approaches.

Cervical Lymph Node Metastasis From Recurrent Glioblastoma Detected by MRI and 2-[18F]FDG PET/CT

ABSTRACT

A 53-year-old man diagnosed with recurrent glioblastoma after multimodal treatment on a follow-up brain MRI. Because of a palpable mass in the neck, the patient underwent a whole-body 2-[18F]FDG PET/CT, which revealed hypermetabolic laterocervical confluent lymphadenopathies. A nodal cervical biopsy indicated distant metastases from glioblastoma. Recent studies have confirmed dural meningeal lymphatics, as part of the glymphatic system, which provide clearance of interstitial solutes from the brain parenchyma into cervical lymphatics. Nodal cervical metastases from glioblastoma, using this pathway, are extremely rare and have been almost unthinkable some years ago.

The Impact of PET/CT on Paediatric Oncology

This review paper will discuss the use of positron emission tomography/computed tomography (PET/CT) in paediatric oncology. Functional imaging with PET/CT has proven useful to guide treatment by accurately staging disease and limiting unnecessary treatments by determining the metabolic response to treatment. ¹⁸F-Fluorodeoxyglucose (2-[¹⁸F]FDG) PET/CT is routinely used in patients with lymphoma. We highlight specific considerations in the paediatric population with lymphoma. The strengths and weaknesses for PET/CT tracers that compliment Meta-[¹²³I]iodobenzylguanidine ([¹²³I]mIBG) for the imaging of neuroblastoma are summarized. 2-[¹⁸F]FDG PET/CT has increasingly been used in the staging and evaluation of disease response in sarcomas. The current recommendations for the use of PET/CT in sarcomas are given and potential future developments and highlighted. 2-[¹⁸F]FDG PET/CT in combination with conventional imaging is currently the standard for disease evaluation in children with Langerhans-cell Histiocytosis (LCH) and the non-LCH disease spectrum. The common pitfalls of 2-[¹⁸F]FDG PET/CT in this setting are discussed.

Imaging features associated with H3 K27-altered and H3 G34-mutant gliomas: a narrative systematic review

Background

Advances in molecular diagnostics accomplished the discovery of two malignant glioma entities harboring alterations in the H3 histone: diffuse midline glioma, H3 K27-altered and diffuse hemispheric glioma, H3 G34-mutant. Radiogenomics research, which aims to correlate tumor imaging features with genotypes, has not comprehensively examined histone-altered gliomas (HAG). The aim of this research was to synthesize the current published data on imaging features associated with HAG.

Methods

A systematic search was performed in March 2022 using PubMed and the Cochrane Library, identifying studies on the imaging features associated with H3 K27-altered and/or H3 G34-mutant gliomas.

Results

Forty-seven studies fulfilled the inclusion criteria, the majority on H3 K27-altered gliomas. Just under half (21/47) were case reports or short series, the remainder being diagnostic accuracy studies. Despite heterogeneous methodology, some themes emerged. In particular, enhancement of H3 K27M-altered gliomas is variable and can be less than expected given their highly malignant behavior. Low apparent diffusion coefficient values have been suggested as a biomarker of H3 K27-alteration, but high values do not exclude this genotype. Promising correlations between high relative cerebral blood volume values and H3 K27-alteration require further validation. Limited data on H3 G34-mutant gliomas suggest some morphologic overlap with 1p/19q-codeleted oligodendrogliomas.

Conclusions

The existing data are limited, especially for H3 G34-mutant gliomas and artificial intelligence techniques. Current evidence indicates that imaging-based predictions of HAG are insufficient to replace histological assessment. In particular, H3 K27-altered gliomas should be considered when occurring in typical midline locations irrespective of enhancement characteristics.

Neuroimaging features of diffuse hemispheric glioma, H3 G34-mutant: A case series and systematic review

BACKGROUND AND PURPOSE

Diffuse hemispheric gliomas, H3 G34-mutant (DHGs-G34m), are newly recognized malignant brain tumors characterized by histone gene mutations. However, the neuroradiologic characteristics of these tumors require elucidation. We reviewed the demographic, clinical, and neuroradiological features of DHGs-G34m.

METHODS

Data were extracted using a database search in MEDLINE, SCOPUS, and Google Scholar in June 2021. Studies assessing pathologically proven DHGs-G34m with each patient's information and neuroradiological findings were included. After screening and reviewing 332 abstracts, 12 articles including 56 cases met the criteria. We also added the findings for three patients evaluated in our hospital. Two board-certified radiologists reviewed all demographic, clinical, and neuroradiological findings of each study. One board-certified pathologist reviewed all pathological data of each study. Kaplan-Meier analyses with log-rank tests were performed to compare the survival between patients with different tumor margin characteristics (well-delineated and ill-defined).

RESULTS

The median patient age at diagnosis was 19 years (range, 6-66 years), and 31/59 patients (52.5%) were men. Supratentorial tumors were observed in all patients (59/59, 100%). Frequent contact with leptomeninges (92.3%) and ependymal regions (87.5%) was observed. The 1- and 2-year survival rates after initial surgery were 66.7% and 40.0%, respectively. DHGs-G34m with ill-defined and well-delineated margins showed significant differences in survival (p = .04).

CONCLUSIONS

DHGs-G34m occur most often in the supratentorial regions of adolescents. Prognosis varies among patients. Evaluation of tumor margins may provide prognostic value.

Glioblastoma multiform with primitive neuronal component, radiological and histology features: a case report

Background

Glioblastoma multiform with primitive neuronal component (GBM-PNC) has been recently defined as a rare variant of glioblastoma multiform (GBM), which shows characteristically pathological pattern of less differentiated areas with small blue cell morphology and neuroectodermic immunophenotype. New studies emphasize its characteristics and differences, which have become vitally important due to the changes in therapeutic management.

Case presentation

We present the case of 57-year-old male patient who onset symptoms were secondarily widespread partial seizures and expression aphasia. Brain magnetic resonance imaging (MRI) reported left enhanced temporal infiltrating lesion, requiring surgery twice throughout two years. At first surgery, pathological samples revealed embryonic tumor of the central nervous system (grade IV, WHO 2016), so PACKER protocol consisting of CSRT (craniospinal radiation) plus weekly vincristine followed by 8 cycles of cisplatin, lomustine and vincristine usually used for medulloblastomas or other primitive neuroectodermal tumors was started. However, due to reappearance of symptoms and progression in MRI, reoperation was performed with definitive diagnosis of GBM-PNC (Grade IV, WHO 2016) and switched to STUPP protocol.

Conclusions

It is important to take into account the chance of this entity when histological, radiological and intraoperative findings orient toward a primitive neural tumor since the presence of GBM could be overlooked leading to mistakes in diagnosis and the therapeutic orientation.

A Rare Manifestation of a Presumed Non-Osteophilic Brain Neoplasm: Extensive Axial Skeletal Metastases From Glioblastoma With Primitive Neuronal Components

Background

Glioblastoma multiforme (GBM) is the most common malignant tumor of the central nervous system. GBM with primitive neuronal component (GBM-PNC) is an aggressive variant identified in 0.5% of GBMs. Extracranial metastasis from GBM-PNC is a rare and challenging situation.

Methods

A special case of early-onset GBM with systemic bone metastasis was enrolled. Clinical data, including patient characteristics, disease course, and serial radiological images were retrieved and analyzed. Tumor tissues were obtained by surgical resections and were made into formalin-fixed paraffin-embedded sections. Histopathological examinations and genetic testing were performed for both the primary and metastatic tumor specimens.

Results

A 20-year-old man suffered from GBM with acute intratumoral hemorrhage of the left temporal lobe. He was treated by gross total resection and chemoradiotherapy following the Stupp protocol. Seven months later, he returned with a five-week history of progressive neck pain and unsteady gait. The radiographic examinations identified vertebral collapse at C4 and C6. Similar osteolytic lesions were also observed at the thoracolumbar spine, pelvic, and left femur. Anterior spondylectomy of C4 and C6 was performed. The resected vertebral bodies were infiltrated with greyish, soft, and ill-defined tumor tissue. One month later, he developed mechanical low-back pain and paraplegia caused by thoracolumbar metastases. Another spine surgery was performed, including T10 total en-bloc spondylectomy, T7-9, L2-3, and L5-S1 laminectomy. After the operation, the patient’s neurological function and spinal stability remained stable. However, he finally succumbed to the rapidly increased tumor burden and died 15 months from onset because of cachexia and multiple organ failure. In addition to typical GBM morphology, the histological examinations identified monomorphic small-round cells with positive immunohistochemical staining of synaptophysin and CD99, indicating the coexistence of PNC. The next-generation sequencing detected pathogenic mutations in TP53 and DNMT3A. Based on above findings, a confirmed diagnosis of systemic metastases from GBM-PNC (IDH-wild type, WHO grade IV) was made.

Conclusions

The present case highlights the occurrence and severity of extensive axial skeletal metastases from GBM-PNC. This rare variant of GBM requires aggressive multimodal treatment including surgery and chemoradiotherapy targeting PNC. The pathological screening of PNC is recommended in patients with early-onset GBM and intratumoral hemorrhage. Surgery for spinal metastasis is appropriate in patients with chemoradioresistance and relatively good general status, with the objectives of restoring spinal stability and relieving spinal cord compression.

Glioblastoma with primitive neuronal component: An immunohistochemical study and review of literature

Glioblastoma with primitive neuronal component, a rare neoplasm, is recognized as a distinct histological pattern of glioblastoma. In this study we report the morphological and immunohistochemical features of three cases of glioblastoma with primitive neuronal component diagnosed at the Institute along with a comprehensive literature review. The cases include: (1) 11-year-old girl with right fronto-parietal lesion, (2) 48-year-old male with right parietal lesion, and (3) 36-year-old male with left fronto-parietal lesion. Case 1 had prior history of glioblastoma. All the cases had classic morphology of glioblastoma along with GFAP-negative and synaptophysin-positive primitive neuronal component. The latter was poorly demarcated from the glial component in case 1, while well-defined in the remaining two. All the three cases exhibited diffuse p53 positivity and a higher MIB-1 labelling index in the neuronal component compared to the glial component. One of them (case 3) was IDH1 R132H-mutant with loss of ATRX expression. None were positive for K27M-mutant H3 or G34R-mutant H3.3. Literature review of 50 published cases of glioblastoma with primitive neuronal component was performed. The age of onset ranged from 3 months to 82 years (mean: 50 years) with M:F of 1.5:1. 18.8% of tumors were IDH-mutant, 87.5% were p53 positive and three cases showed H3F3A gene mutations. There was a greater propensity for neuraxial dissemination, noted in 20% of cases. Overall survival of glioblastoma with primitive neuronal component was similar to that of IDH-wildtype glioblastoma (13 months) which was significantly shorter compared to the overall survival of IDH-mutant glioblastoma (33.6 months).

Case series of diffuse extraneural metastasis in H3F3A mutant high-grade gliomas: Clinical, molecular phenotype and literature review

H3K27M and H3.3G34R/V mutations have been identified in pediatric high-grade gliomas (pHGG), though extraneural metastases are rarely reported and poorly characterized. Three pHGG patients from two institutions were identified with extraneural metastasis, harboring histone mutations. Their clinical, imaging and molecular characteristics are reported here. A 17-year old female presented with supratentorial H3.3G34R-mutant glioma with metastatic osseous lesions in the spine, pelvis, bone marrow, pleural effusion and soft tissue of pelvis. Bone marrow biopsy and soft tissue of pelvis biopsy showed neoplastic cells positive for P53. A 20-year old female was diagnosed with H3F3A H3K27M-mutant thalamic glioma. She developed diffuse sclerotic osseous lesions. Biopsy of an osseous lesion was non-diagnostic. A 17-year old female presented with a H3F3A H3K27M-mutant diffuse midline glioma with diffuse spinal cord metastasis. She further developed multifocal chest lymphadenopathy, pleural effusions, and a soft tissue mass in the abdominal wall. The latter was positive for H3K27M mutation. We present the first case series of pHGG with H3F3A mutation and diffuse extraneural dissemination, describing their clinical and molecular profile.