Neuroradiologic characteristics of astroblastoma and systematic review of the literature: 2 new cases and 125 cases reported in 59 publications

Posterior fossa astroblastoma: a case report of an extremely rare tumor with challenging diagnosis in a child and a review of literature

A 7-year-old boy presented to the hospital with recurrent nausea and vomiting over 2 weeks. A cranial MRI revealed a large heterogeneous lesion in the posterior fossa extending from the fourth ventricle to the foramen magnum with contact to the brainstem. The lesion showed moderate diffusion restriction and multiple small cystic components. The child underwent gross total resection. The primary histological findings suggested proliferative active tumor without further definition. The extended histological examination 3 weeks later confirmed the diagnosis of astroblastoma. Due to complete resection and full recovery of the patient, watchful waiting with radiological follow-up was recommended. Astroblastoma is an extremely rare tumor especially in the posterior fossa. However, it should be considered as a differential diagnosis in every tumor presenting the discussed radiological and histological features, especially in young aged patients.

Supra-tentorial Ependymomas with ZFTA Fusion, YAP1 Fusion, and Astroblastomas, MN1-altered: Characteristic Imaging Features

PURPOSE

Supratentorial (ST) ependymoma subgroups are defined by two different fusions with different prognoses. Astroblastomas, MN1-altered, have ependymal-like histopathologic features and represent a differential diagnosis in children. We hypothesized that ZFTA-fused ependymoma and YAP1-fused ependymoma on the one hand, and astroblastoma, MN1-altered, on the other hand, show different MRI characteristics.

METHODS

We retrospectively analyzed the preoperative imaging of 45 patients with ST ependymoma or astroblastoma between January 2000 and September 2020, blinded to histomolecular grouping. Several characteristics, such as location, tumor volume, calcifications, solid/cystic component, and signal enhancement or diffusion were evaluated. We compared imaging characteristics according to their molecular subtype (ZFTA-fused, YAP1-fused, and astroblastoma, MN1-altered).

RESULTS

Thirty-nine patients were classified as having an ependymoma, 35 with a ZFTA fusion and four with a YAP1 fusion, and six as having an astroblastoma, MN1-altered. YAP1-fused ependymomas were more likely to involve at least 3 lobes than ZFTA-fused ependymomas. Astroblastomas were located in the frontal lobe in 100% of the tumors versus 49% of the ependymomas. Cerebral blood flow by arterial spin labeling was higher in astroblastomas than in ependymomas. There were no differences in the other characteristics between the molecular groups. All the tumors showed common features: intra-axial extra-ventricular tumors, very frequent contrast enhancement (39/43, 91%), a cystic/necrotic component (41/45, 91%), restricted diffusion (32/36, 89%), calcifications (15/18, 83%), and peri-tumoral edema (38/44, 86%).

CONCLUSION

The distinction between ST ependymoma subtypes and astroblastomas can be guided by several imaging features. These tumors share common imaging features that may help to differentiate ST ependymomas and astroblastomas from other pediatric ST tumors.

The 2021 WHO Classification for Gliomas and Implications on Imaging Diagnosis: Part 2-Summary of Imaging Findings on Pediatric-Type Diffuse High-Grade Gliomas, Pediatric-Type Diffuse Low-Grade Gliomas, and Circumscribed Astrocytic Gliomas

The fifth edition of the World Health Organization (WHO) classification of central nervous system tumors published in 2021 advances the role of molecular diagnostics in the classification of gliomas by emphasizing integrated diagnoses based on histopathology and molecular information and grouping tumors based on genetic alterations. This Part 2 review focuses on the molecular diagnostics and imaging findings of pediatric-type diffuse high-grade gliomas, pediatric-type diffuse low-grade gliomas, and circumscribed astrocytic gliomas. Each tumor type in pediatric-type diffuse high-grade glioma mostly harbors a distinct molecular marker. On the other hand, in pediatric-type diffuse low-grade gliomas and circumscribed astrocytic gliomas, molecular diagnostics may be extremely complicated at a glance in the 2021 WHO classification. It is crucial for radiologists to understand the molecular diagnostics and imaging findings and leverage the knowledge in clinical practice. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Systemic cellular viroimmunotherapy for canine high-grade gliomas

BACKGROUND

Oncolytic viruses constitute a growing field of interest, both in human and veterinary oncology, given that they are particularly helpful for treating non-surgical tumors and disseminated cancer, such as high-grade gliomas. Companion dogs present malignant gliomas with biological, genetic, phenotypic, immunological, and clinical similarities to human gliomas. These features favor comparative approaches, leading to the treatment of canine oncological patients to achieve translational applications to the human clinic. The systemic administration of oncolytic viruses presents a challenge due to their limitations in effectively targeting tumors and metastases. Therefore, the aim of this study is to evaluate the safety and antitumor activity of a virotherapy used in spontaneous canine tumors.

METHODS

Ten dogs with high-grade rostrotentorial gliomas underwent weekly systemic endovenous cellular virotherapy with dCelyvir (canine mesenchymal stem cells infected with the canine oncolytic adenovirus ICOCAV17) for 8 weeks. Efficacy was determined in seven dogs according to the Response Assessment in Veterinary Neuro-Oncology criteria considering clinical status and MRI measurements. Medical history, physical and neurological examinations, and vaccination status were evaluated prior to and during follow-up. Safety was evaluated by physical examinations and hematological and biochemical changes in peripheral blood. Immune populations were analyzed by flow cytometry in peripheral blood and by gene expression and immunohistochemistry in the tumor microenvironment.

RESULTS

The treatment was well tolerated and major adverse effects were not observed. Two dogs had partial responses (76% and 86% reduction in tumor size), and 3/7 showed stable disease. ICOCAV17 was detected in peripheral blood in nine dogs, and a correlation between the ICOCAV17 particles and anti-canine adenovirus (CAV) antibodies was observed. ICOCAV17 was detected in 3/9 tumor tissues after necropsies. Regarding tumor-infiltrating lymphocytes, the dogs with disease stabilization and partial response tended to have reduced memory B-cell infiltration and increased monocyte/macrophage lineage cells.

CONCLUSIONS

These findings indicate that dCelyvir is safe and presents efficacy in canine rostrotentorial high-grade gliomas. These data are relevant to the ongoing phase Ib regulated human clinical trial that is administering this virotherapy to children, adolescents, and young adults with diffuse pontine glioma. Celyvir should be further explored as a treatment in veterinary and human neuro-oncology.

Thirteen-year long-term follow-up in a rare case of anaplastic astroblastoma: What makes the difference?

Background:

Astroblastomas are uncommon neuroepithelial tumors of the central nervous system with a distinct, yet, controversial radiological, histological, and molecular profile. Debatable differences between low- and high-grade astroblastoma have been reported in the medical literature; indeed, despite the increasing relevance of molecular genetic profiling in the realm of astroblastoma, its application is still in its early stages. As a result, the diagnostic criteria for astroblastoma remain undecided with yet no real consensus on the most ideal management.

Case Description:

This report describes a case of astroblastoma diagnosed 13 years ago in a young woman who despite six episodes of recurrence, transformation, and progression was able to retain a perfomace status of 0 by World Health Organization standard, throughout.

Conclusion:

This report discusses the clinical, radiological, histological features, and management of this rare tumor with an extraordinarily long survival, with an aim to strengthen the literature on management options. To the best of our knowledge, this is the longest surviving case of anaplastic astroblastoma reported in the available medical literature.

Clinicoradiological and histopathological characteristics and treatment outcomes of cerebral astroblastoma in children: a single-institution experience

OBJECTIVE

Astroblastoma (AB) is a rare glial tumor. The optimal treatment and prognosis of this tumor remain unclear. The authors retrospectively analyzed the clinical characteristics, neuroimaging findings, histopathological results, and treatment outcomes of 7 patients with AB.

METHODS

The study comprised 7 patients with pathologically proven AB who were surgically treated at Samsung Medical Center from November 1994 to January 2019. Clinicoradiological, histopathological, and surgical records were reviewed.

RESULTS

The patients included 5 girls (71.4%) and 2 boys (28.6%), with a median age of 13 years. All patients showed contrast enhancement on preoperative MRI: 5 ABs (71.4%) showed a concomitant solid and cystic appearance, and 2 (28.6%) demonstrated a solid appearance. ABs in 6 patients (85.7%) showed a well-circumscribed, characteristic "bubbly" appearance on T2-weighted MRI. Gross-total resection (GTR) was achieved in all cases (100%). Six patients (85.7%) were diagnosed with high-grade AB and 1 (14.3%) with low-grade AB. Six (85.7%) of the 7 patients received adjuvant treatment after resection, including 5 (83.3%) with AB who received chemotherapy and radiotherapy and 1 (16.7%) who received proton therapy alone. The median clinical follow-up duration was 96 months (range 48-189 months). Two patients experienced recurrence, and all patients in this series were alive at the last follow-up.

CONCLUSIONS

In this study, the clinicoradiological and histopathological features of AB were described. Based on the authors' limited experience with 7 cases, resection with the goal of GTR is currently the mainstream treatment for AB, and adjuvant radiation treatment should be considered after surgery.

Neuroimaging of astroblastomas: A case series and systematic review

BACKGROUND AND PURPOSE

Astroblastoma is a rare type of glial tumor, histologically classified into two types with different prognoses: high and low grade. We aimed to investigate the CT and MRI findings of astroblastomas by collecting studies with analyzable neuroimaging data and extracting the imaging features useful for tumor grading.

METHODS

We searched for reports of pathologically proven astroblastomas with analyzable neuroimaging data using PubMed, Scopus, and Embase. Sixty-five studies with 71 patients with astroblastomas met the criteria for a systematic review. We added eight patients from our hospital, resulting in a final study cohort of 79 patients. The proportion of high-grade tumors was compared in groups based on the morphology (typical and atypical) using Fisher's exact test.

RESULTS

High- and low-grade tumors were 35/71 (49.3%) and 36/71 (50.7%), respectively. There was a significant difference in the proportion of high-grade tumors based on the tumor morphology (typical morphology: high-grade = 33/58 [56.9%] vs. atypical morphology, 2/13 [15.4%], p = .012). The reviews of neuroimaging findings were performed using the images included in each article. The articles had missing data due to the heterogeneity of the collected studies.

CONCLUSIONS

Detailed neuroimaging features were clarified, including tumor location, margin status, morphology, CT attenuation, MRI signal intensity, and contrast enhancement pattern. The classification of tumor morphology may help predict the tumor's histological grade, contributing to clinical care and future oncologic research.

Supratentorial extraventricular ependymoma presenting calvarial erosion: A report of 3 cases

Calvarial erosion is an infrequent manifestation associated with oligodendrogliomas, astrocytomas, dysembryoplastic neuroepithelial tumors, astroblastomas, glioblastomas, and meningiomas. Anaplastic ependymoma (AE), a rare malignant form of ependymoma, commonly results in poor prognosis. During the last 12 years, six patients were diagnosed with supratentorial ependymomas. All of them were AEs with extraventricular location identified in the right parietal, left parietal, and left frontal lobes, respectively. Three of them, 7-, 15, and 17-year-old male patients, presented focal calvarial erosion with smooth contour. Calvarial erosion may be a diagnostic hallmark of supratentorial AEs.

Atypical meningeal hemangiopericytoma presenting with punched-out calvarial erosion

Meningeal hemangiopericytoma (HPC) is an infrequent but distinct entity affecting the craniospinal axis. A previously healthy 48-year-old man sustained a gradually progressing motor weakness in the left lower extremity. CT showed a hyperdense mass in the right frontal lobe. On MRI, it was 29 × 30 × 36 mm in dimension, appeared isointense on T1 and hyperintense on T2, and was intensely enhanced with erosive changes in the inner table adjacent to the tumor. The patient underwent tumor resection. Reflection of the bone flap revealed a punched-out erosion in the inner table with a defect of the dura over the upper part of the tumor. Microscopic findings were consistent with grade III HPC with dural invasion. A punched-out calvarial erosion and dural defect caused by an extra-axial tumor may be a high-grade HPC that requires extensive surgical resection.

Posterior fossa astroblastoma in a child: a case report and a review of the literature

A 4-year-old girl presented to the hospital with a progressive headache, difficulty walking, and persistent daily vomiting for 3 weeks. Papilledema was observed on fundoscopic examination. A large left cerebellovermian tumor with "bubbly" appearance was discovered. Total removal of the tumor mass was performed, and a diagnosis of low-grade astroblastoma was made. Adjuvant radiotherapy was performed due to the risk of recurrence. The patient is disease-free and has been kept on close follow-up for 6 months. The occurrence of posterior fossa astroblastoma has been rarely reported in the literature. Thus, when a "bubby" appearance enhancing cystic solid tumor is located on the cerebellar hemisphere in a child, an astroblastoma should also be included in the differential diagnosis.

Role of DNA Methylation Profile in Diagnosing Astroblastoma: A Case Report and Literature Review

Astroblastoma is a rare tumor of the central nervous system (CNS) with uncertain clinical behavior. Recently, DNA methylation profiling has been shown to provide a highly robust and reproducible approach for the classification of all CNS tumors across different age groups. By using DNA methylation profiling, a subset of CNS high-grade tumors with astroblastoma-like morphology characterized by the meningioma 1 gene (MN1) rearrangements, has been identified; they were termed “CNS high-grade neuroepithelial tumors with MN1 alteration” (CNS-HGNET-MN1). Here, we describe a case of CNS-HGNET-MN1 diagnosed by DNA methylation profiling, using Illumina Infinium HumanMethylationEPIC BeadChip (EPIC), that offers the opportunity to conduct a brief literature review. The patient presented with an episode of partial seizures involving the right hemisoma. A gross total resection was performed. No other treatment was proposed in light of the histological and molecular findings. After 21 months, the patient is disease-free in good clinical conditions. Also in view of this case, we recommend DNA-methylation profiling as an important tool for diagnosis and more effective patient stratification and management.

[Astroblastoma: A rare glial tumor]

Astroblastoma is a rare neuroepithelial tumor most commonly seen in children and young adults. Due to its rarity, this tumor can be easily misdiagnosed as its classification, histogenesis and therapeutic management are still being discussed. We report the case of a 21 year old man, who presented at the Emergency Room for loss of consciousness. He reported a history of headaches, vomiting and decreased visual acuity. The CT and MRI showed a left temporoparietal solid-cystic mass with heterogeneous enhancement and perilesional edema. The patient underwent a total mass resection. On histopathological examination, tumor cells were organized in perivascular pseudorosettes which are typically encountered in astroblastoma, without neither necrosis nor endothelial hyperplasia. They had broad processes and rounded nuclei without any mitotic activity. Immunochemistry stains confirmed the diagnosis by showing a positive reactivity for GFAP, EMA, vimentin and S100. Astroblastoma is a rare glial tumor of uncertain origin. Clinical presentation and imaging are nonspecific. Therefore, its diagnosis is based on histopathologic findings: typical perivascular pseudorosettes. However, similar histological pattern may be seen in other glial neoplasms. In the 2016 WHO Classification, astroblastoma is among the "other glial neoplasms" without a grading system. So far, there are no reliable prognosis factors for this tumor; however, two entities have been described: well differenciated astroblastoma (considered as low grade) and anaplastic/malignant astroblastomas (considered as high grade). Gross total resection is the treatment of choice for astroblastomas. Adjuvant therapy is still controversial. This case illustrates a cerebral tumor which is rarely encountered in practice and that can cause diagnostic problems and subsequently, inadequate treatment.

Co-occurrence of astrocytoma and astroblastoma: Case report and literature review

A 41-year-old man presented to us with left arm and leg weakness and mild word finding difficulties. His preoperative magnetic resonance imaging (MRI) demonstrated abnormal T1 and T2 signal changes in the right temporal lobe and basal ganglia, indicative of possible glioma. An awake craniotomy for right temporal lobectomy was performed and the tumor was resected. Full pathologic workup later revealed the patient had two distinct tumors occurring simultaneously, anaplastic astrocytoma and astroblastoma. We review the literature regarding the treatment of anaplastic astrocytoma and astroblastoma and discuss their co-occurrence.

Astroblastoma in a Young Female Patient: A Case Report and Literature Review of Clinicopathological, Radiological and Prognostic Characteristics and Current Treatment Strategies

Astroblastoma is an uncommon glial tumor with predominant manifestation in the young age. Herein, we report a case of 18-year-old astroblastoma female patient who presented with history of two months headache. Magnetic resonance imaging (MRI) of the brain demonstrated well circumscribed, intra-axial abnormal signal intensity lesion (size=5×4 cm²) in the right parieto-occipital region of the brain. The patient underwent complete surgical resection of the gross tumor, as confirmed by an early post-surgical MRI (i.e., within 24 hours of surgery). Histopathological examination revealed neoplastic lesion exhibiting perivascular pseudo-rosettes with centrally hyalinized blood vessel and focal nuclear pleomorphism. Immunohistochemistry staining illustrated reactivity for glial fibrillary acidic protein and integrase interactor 1 (INI-1). These features rendered the diagnosis of astroblastoma. A comprehensive review of the current literature to summarize the clinicopathological and radiological characteristics, prognostic factors and current treatment strategies of astroblastomas is also presented. Our study would expand the pool of this uncommon tumor towards its better understanding and optimal treatment.

Patterns of care and survival outcomes in patients with astroblastoma: an individual patient data analysis of 152 cases

BACKGROUND

Astroblastoma (AB) is a rare tumor with significant dilemma regarding diagnostic criteria, behavior, and optimum treatment.

MATERIALS AND METHODS

We searched PubMed, Google Search, and Cochrane Library for eligible studies with the following search words: astroblastoma, high-grade astroblastoma, and anaplastic astroblastoma till July 1, 2016, published in English language and collected data regarding age, sex, site of disease, pathological grade, treatment received, and survival.

RESULTS

Data of 152 patients were retrieved from 63 publications. Median age was 16 years (range 0-71). Females were affected twice more frequently than male (70.3 vs. 29.7%). Tumors were most commonly located in the frontal (39%) followed by parietal lobe (26.7%). Fifty-two and 25% of the patients had headache and seizure at presentation, 76.3% of the patients underwent a gross total resection, 41 out of 89 had a high-grade tumor, and 56 patients received adjuvant radiation with a median dose of 54 Gy (range 20-72). Adjuvant chemotherapy was used in 23 patients. Temozolomide was the most common drug used in 30% of the patients. A combination of cisplatin, etoposide with vincristine, or ifosfamide was used in 17%. Median follow-up duration was 37 months (range 1-238). Median progression-free survival and OS were 36 and 184 months, respectively. Patients with a higher-grade tumor had significantly worse OS with HR 5.260 and p = 0.001. Forty patients experienced local progression. Sixty-five percent patients underwent surgery while 50% underwent radiation as salvage.

CONCLUSION

AB has two distinct grades with higher-grade tumors having significantly poor survival. Maximal safe surgery followed by adjuvant radiation and temozolomide should be advocated for these tumors.