Astroblastoma with rhabdoid features and favorable long-term outcome: Report of a case with a 12-year follow-up

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.

High-Grade Intraventricular Astroblastoma in a Young Adult: A Rare and Controversial Tumor to Manage

Astroblastoma is a rare primary central nervous system tumor of controversial site of origin. They account for 0.45-2.8% of all primary neuroepithelial central nervous system. It has been reported in paediatric age group with bimodal age distribution affecting more females with male to female ratio being 1:11. Astroblastomas are controversial and challenging tumors in terms of diagnosis and therapeutics. Since it carries an unpredictable disease course it needs a regular follow up even for low grade tumor. Authors have tried various schedules of post op radiotherapy after maximum safe resection. Various chemotherapeutic drugs combination have also been tried without much success. We here report a 35 years old female patient who was diagnosed with high grade astroblastoma referred for post-operative radiotherapy after gross total resection. Since it is extremely rare tumor, its treatment still not well defined and also makes it difficult conduct studies to examine tumor characteristics.

Extra-axial anaplastic astroblastoma in a 67-year-old woman

Astroblastoma is a rare glial neoplasia of the central nervous system. It is histologically defined by the presence of neoplastic cells with non- or slightly tapering processes arranged around blood vessels (astroblastic rosettes) and conventionally subdivided into well-differentiated and anaplastic. It commonly affects children and young adults, although cases and due to its superficial location in the brain cortex, it can mimic an extra-axial mass on magnetic resonance imagining. Herein, we describe a unique case of pure extra-axial anaplastic astroblastoma in an elderly woman. Awareness that astroblastoma may be also extra-axial and affect older subjects, may be helpful for its identification and differential diagnosis toward more common entities at this site and age of onset, and for appropriate therapeutic management as well.

Astroblastoma - a rare and challenging tumor: a case report and review of the literature

Background

Astroblastoma is a controversial and an extremely rare central nervous system neoplasm. Although its histogenesis has been clarified recently, controversies exist regarding its cellular origin and validity as a distinct entity. Because of its extreme rarity and because its common features are shared with other glial neoplasms, this tumor is prone to misdiagnosis and remains challenging not only in terms of diagnosis and classification but also in the subsequent management. This case report describes a new case of astroblastoma. It discusses clinical, radiologic, pathological, and therapeutic features and differential diagnosis of this rare neoplasm, with a review of the recent literature.

Case presentation

We report the case of an 8-year-old Moroccan girl who presented with a 1-year history of epileptic seizure, headache, and decreased visual acuity. Cranial magnetic resonance imaging revealed a right occipito-temporal mass. A tumor resection was performed and histological examination combined with immunohistochemical study confirmed the diagnosis of low-grade astroblastoma.

Conclusions

Astroblastoma is a very rare primary brain tumor. Its diagnosis is often challenging because of the astroblastic aspects that can be found in astrocytic tumors, in ependymomas, and in non-neuroepithelial tumors. Considerable confusion surrounds its histogenesis and classification. The low incidence rate makes it difficult to conduct studies to examine tumor characteristics.

Multimodal molecular analysis of astroblastoma enables reclassification of most cases into more specific molecular entities

Astroblastoma is a rare and controversial glioma with variable clinical behavior. The diagnosis currently rests on histologic findings of a circumscribed glioma with astroblastomatous pseudorosettes and vascular hyalinization. Immunohistochemical studies have suggested different oncogenic drivers, such as BRAF p.V600E, but very few cases have been studied using genome-wide methodologies. Recent genomic profiling identified a subset of CNS embryonal tumors with astroblastoma-like morphology that harbored MN1 gene fusions, termed "CNS high-grade neuroepithelial tumors with MN1 alteration" (CNS-HGNET-MN1). To further characterize the genetic alterations that drive astroblastomas, we performed targeted next-generation sequencing (NGS) of 500 cancer-associated genes in a series of eight cases. We correlated these findings with break-apart fluorescence in situ hybridization (FISH) analysis of the MN1 locus and genome-wide DNA methylation profiling. Four cases showed MN1 alteration by FISH, including two pediatric cases that lacked other pathogenic alterations, and two adult cases that harbored other cancer-associated gene mutations or copy number alterations (eg, CDKN2A/B homozygous deletion, TP53, ATM and TERT promoter mutations). Three of these cases grouped with the CNS-HGNET-MN1 entity by methylation profiling. Two of four MN1 intact cases by FISH showed genetic features of either anaplastic pleomorphic xanthoastrocytoma (BRAF p.V600E mutation, CDKN2A/B homozygous deletion and TERT promoter mutation) or IDH-wildtype glioblastoma (trisomy 7, monosomy 10, CDK4 amplification and TP53, NRAS and TERT promoter mutations) and these cases had an aggressive clinical course. Two clinically indolent cases remained unclassifiable despite multimodal molecular analysis. We conclude that astroblastoma histology is not specific for any entity including CNS-HGNET-MN1, and that additional genetic characterization should be considered for astroblastomas, as a number of these tumors likely contain a methylation profile or genetic alterations that suggest classification as other tumor entities. Our heterogeneous molecular findings help to explain the clinical unpredictability of astroblastoma.

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.

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

BACKGROUND

Astroblastoma is a rare tumor of uncertain origin most commonly presenting in the cerebrum of children and young adults. The literature contains only case reports and small series regarding its radiologic features. This systematic review is the largest study of imaging findings of astroblastoma to date and serves to identify features that might differentiate it from other neoplasms.

OBJECTIVE

This study describes the imaging features of astroblastoma based on a systematic review of the literature and two new cases.

MATERIALS AND METHODS

We conducted a PubMed and Google Scholar database search that identified 59 publications containing 125 cases of pathology-confirmed astroblastoma, and we also added two new cases from our own institution. Data collected include patient age, gender, tumor location, morphology, calcifications and calvarial changes. We recorded findings on CT, MRI, diffusion-weighted imaging (DWI), MR spectroscopy, positron emission tomography (PET) and catheter angiography.

RESULTS

Age at diagnosis ranged 0-70 years (mean 18 years; median 14 years). Female-to-male ratio was 8:1. Of 127 cases, 66 reported CT, 78 reported MRI and 47 reported both findings. Not all authors reported all features, but the tumor features reported included supratentorial in 96% (122/127), superficial in 72% (48/67), well-demarcated in 96% (79/82), mixed cystic-solid in 93% (79/85), and enhancing in 99% (78/79). On CT, 84% (26/31) of astroblastomas were hyperattenuated, 73% (27/37) had calcifications and 7 cases reported adjacent calvarial erosion. Astroblastomas were hypointense on T1-W in 58% (26/45) and on T2-W in 50% (23/46) of MRI sequences. Peritumoral edema was present in 80% (40/50) of cases but was typically described as slight. Six cases included DWI findings, with 100% showing restricted diffusion. On MR spectroscopy, 100% (5/5) showed nonspecific tumor spectra with elevated choline and decreased N-acetylaspartate (NAA). PET revealed nonspecific reduced uptake of [F-18] 2-fluoro-2-deoxyglucose ((18)F-FDG) and increased uptake of [11C]-Methionine in 100% (3/3) of cases. Catheter angiography findings (n=12) were variable, including hypervascularity in 67%, arteriovenous shunting in 33% and avascular areas in 25%.

CONCLUSION

Astroblastomas occur most often in adolescent girls. Imaging often shows a supratentorial, superficial, well-defined, cystic-solid enhancing mass. On CT, most are hyperattenuated, have calcifications, and may remodel adjacent bone if superficial. MRI characteristically reveals a hypointense mass on T1-W and T2-W sequences with restricted diffusion. MR spectroscopy, PET and catheter angiography findings are nonspecific.

A case of cerebral astroblastoma with rhabdoid features: a cytological, histological, and immunohistochemical study

Astroblastoma is a rare neuroepithelial neoplasm of unknown origin, usually occurring in children and young adults. Here we report a case of astroblastoma with uncommon features in an 18-year-old female. The tumor was a well-circumscribed cystic and solid mass with marked gadolinium enhancement in the right frontal lobe. Cytological examination showed polarized monopolar cells with diminished cohesiveness. Tumor cells possessed eccentric round to oval nuclei with abundant eosinophilic cytoplasm, sometimes having cytoplasmic processes. Histopathologically, the tumor showed perivascular pseudorosettes with prominent vascular sclerosis. Foam cells were frequently infiltrated around blood vessels and among tumor cells. In some areas, a solid growth pattern of plump tumor cells with abundant inclusion-like eosinophilic cytoplasm showing rhabdoid appearance was observed. The immunohistochemical study revealed strong and diffuse positivity for vimentin and epithelial membrane antigen. Tumor cells were focally positive for glial fibrillary acidic protein and cytokeratin AE1/AE3. Nuclear immunoreactivity for INI1 protein was evident. The Ki-67 labeling index was 10.8%. This tumor was finally diagnosed as low-grade astroblastoma and the patient had no evidence of recurrence without postoperative radiotherapy or chemotherapy during the last 6 months of follow-up. This report describes novel cytological, histopathological, and immunohistochemical features of the rare tumor.

High-grade astroblastoma in a child: Report of one case and review of literature

Background:

Astroblastoma is a rare glial neoplastic lesion that affects children and adolescents; its histogenesis remains uncertain. It is considered to account for 0.5% of all glial neoplasms, and two different subtypes have been defined based upon histologic characteristics.

Case Description:

We present the case of a 9-year-old girl who presented with headache, motor symptoms, and seizures few days before she was admitted to our institution. Computed tomography (CT) and magnetic resonance imaging (MRI) scans showed an intra-axial heterogeneous frontoparietal lesion with a striking “bubbly” appearance in MRI T2-weighted sequences and features of intracranial hypertension. Gross total resection of the tumor was achieved and the histopathologic diagnosis revealed high-grade astroblastoma. We reviewed the current published cases of astroblastoma to highlight the demographic, clinical, radiologic, and pathologic data.

Conclusion:

Astroblastomas are a distinct clinicopathologic entity, with well-described radiologic, pathologic, and cytogenetic features. Its recurrence is high and efforts must be made to elucidate the role and usefulness of radiotherapy and chemotherapy in these tumors.

Astroblastoma: report of two cases with unexpected clinical behavior and review of the literature

Astroblastoma is a rare, mostly supratentorial glial tumor, occurring predominantly in children and young adults with female preponderance. Due to the rarity, with only about 230 reported cases, treatment strategies are still to be discussed. We describe two more cases to add to the clinical experiences with this tumor entity. In both of these cases, the clinical behavior did not follow the expectations based on histopathological classification. Case 1: A sixteen-year old female presented with a six month history of intermittent headaches, nausea and dizziness. MRI scans revealed a left parietooccipital mass lesion with bubbly contrast enhancement and marked peritumoral edema. After gross total tumor resection the histology gave the diagnosis of low grade astroblastoma. Fifteen months later, the patient was operated on a local recurrence and received postoperative radiotherapy, with the histology still being that of low grade astroblastoma. Two years later, a meningeally based tumor nodule frontal of the former tumor bed was removed, now diagnosed as high grade astroblastoma. Eighteen months later, a fourth operation with excision of two more meningeally based tumor nodules of high-grade astroblastoma followed. Chemotherapy was suggested, but the patient decided against it. The last MRI follow-up 14 months after last operation showed no further recurrence so far. Case 2: A 24-year old female presented with a four week history of vomiting and headaches with focal seizures affecting her left arm. CT and MRI scans revealed a superficial partly cystic right temporal mass lesion with few edema and macrocalcifications and adjacent bone atrophy. Despite dural invasion, total tumor resection could be performed. MRI scans six months later showed no recurrence. The patient refused further MRI controls but did not show any clinical signs or symptoms suggesting tumor recurrence four years after the operation. In order to find more predictive tools that might help to determine the individual clinical course and treatment, we performed a review of the literature, analyzing 29 cases with detailed data on clinical history, MRI/CT characteristics, histopathological subtyping, treatment details and a follow-up of at least 12 months. We found, that low-grade astroblastoma with marked peritumoral edema has a tendency to early recurrence and suggest that it should be treated by combined surgery and radiotherapy. In high-grade astroblastoma with well defined tumor borders and few peritumoral edema, the prognosis may be better than expected for a high-grade glioma, if GTR is possible.