Astroblastoma: clinicopathologic features and chromosomal abnormalities defined by comparative genomic hybridization

Astroblastoma: beside being a tumor entity, an occasional phenotype of astrocytic gliomas?

The diagnosis of astroblastoma is based on a typical histological aspect with perivascular distribution of cells sending cytoplasmic extensions to the vessels and vascular hyalinization. These criteria are useful for standardizing the identification of the tumor, but, in spite of this, there are discrepancies in the literature concerning the age distribution and the benign or malignant nature of the tumor. Three cases are discussed in this study: Case 1 was a typical high-grade astroblastoma; Case 2 was an oligodendroglioma at the first intervention and an oligoastrocytoma at the second intervention with typical perivascular arrangements in the astrocytic component; Case 3 was a gemistocytic glioma with malignant features and typical perivascular arrangements. Genetic analysis showed genetic alterations that are typical of gliomas of all malignancy grades. Using the neurosphere assay, neurospheres and adherent cells were found to have developed in Case 1, while adherent cells only developed in Case 2, in line with the stemness potential of the tumors. The cases are discussed in relation to their diagnostic assessment as astroblastoma, and it is hypothesized that the typical perivascular distribution of cells may not indicate a separate and unique tumor entity, but may be a peculiarity that can be acquired by astrocytic gliomas when an unknown cause from the tumor microenvironment influences the relationship between vessels and tumor cells.

Intraventricular Astroblastoma in an Infant: A Case Report and Review of the Literature

Astroblastomas are rare intracranial tumours of uncertain origin and are commonly present in the supratentorial compartment. Astroblastomas often affect children and young adults. Their occurrence in an intraventricular location, in an infant, is extremely uncommon. We describe a 1-year-old boy who presented with features of raised intracranial pressure. An MRI scan revealed an intralateral ventricular tumour. Complete excision was performed. Its histopathological examination revealed features consistent with astroblastoma. A follow-up MRI scan after 9 months did not show any residual tumour, and the patient was followed up without any adjuvant therapy. The radiological and histopathological characteristics of this tumour are described in our report.

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.

Pediatric astroblastoma: a rare case with a review of the literature

Astroblastoma is a rare glial tumor with uncertain histopathological origin and unpredictable clinical behavior. We present a case of an 11-year-old girl who presented with headache and blurring of vision for 2 months. A well-demarcated mass was found in the right frontoparietal lobe on a brain MRI. The patient was treated with total tumor resection followed by postoperative radiotherapy. Histologically, the features were suggestive of high-grade astroblastoma. The patient is alive and disease free 23 months after surgery. The characteristic radiological and histopathological features and treatment of this case are described with a literature review.

Astroblastoma with bone invasion

Astroblastoma is a rare tumor belonging to the family of primary glial neoplasms. They are classified as neuroepithelial tumors; however, the World Health Organization grading is still not established. We report the case of a 4-year-old child who presented with an intra-axial space occupying lesion which turned out to be an astroblastoma. A complete excision was done and there was no recurrence at 20 months follow-up. This case report highlights the presence of such unusual tumor with invasion to the calvarium and reviews the current literature.

Anaplastic astroblastoma: a rare glial tumour

Astroblastoma is a rarely diagnosed primary brain neoplasm whose histogenesis has been clarified recently. It occurs in children and young adults and presents as a well-circumscribed, contrast enhancing lesion in the cerebral hemisphere. Here the authors present a case of 25-year-old woman with an astroblastoma in the left frontal convexity that was excised. The characteristic radiological and histopathological features of this case are described. An astroblastoma should be included in the differential of a localised brain tumour, especially in a young patient.

Angiocentric glioma: a case report and review of the literature

Angiocentric glioma (AG) is a rare central nervous system (CNS) neoplasm that was only recently recognized by the World Health Organization (WHO). AG occurs in a broad age range, shows no gender predilection, and arises superficially in the cerebrum, usually resulting in medically intractable seizures. Most cases are cured by surgical excision alone, consistent with a WHO grade I neoplasm. We report a case of an AG in the right frontal lobe of a 57-year-old female, emphasizing the cytologic and immunohistochemical features, including confirmation and comparison with the surgical specimen. To our knowledge, this is the first report detailing the cytology of AG, including demonstration of important diagnostic findings that were only appreciated in the cytologic preparations and not in the smears or the surgical specimen. We also compare and contrast AG to other entities in the differential diagnosis and include a review of the literature.

Glioma diagnosis: immunohistochemistry and beyond

Clinicians and pathologists have been inundated by published reports of new and potentially interesting diagnostic, prognostic, and putative predictive "markers" whose expression (or loss) holds great promise for more enlightened diagnoses and ultimately better patient care. Although an understanding of therapeutically (and possibly diagnostically) relevant pathways of glioblastoma may be at hand, significant challenges remain. Many immunohistochemical and genetic tests have proven to be useful in the stratification of clinical trials, whereas the utility of many others for the day-to-day practice of pathology awaits further study and validation. The importance of critical literature review and careful consideration of practical issues such as test standardization, compliance, cost-effectiveness, and availability must all be considered before implementing any new diagnostic test. This review will focus on the role of immunohistochemistry in the routine diagnosis of astrocytic and oligodendrocytic tumors and in assisting with the diagnosis of some less common gliomas that have ependymal-like features. It will conclude with a summary of molecular and genetic studies, which not only hold great promise for improved diagnosis, but also reveal prognostic information on disease outcome and predict response to treatment or provide biologic targets for novel therapies.

Anaplastic astroblastoma presenting as massive, sudden-onset, intraparenchymal hemorrhage

Astroblastoma is a rare primary glial tumor of children and young adults, typically located in the cerebral hemispheres and presenting as a well-circumscribed, nodular, often cystic enhancing mass. The existence of astroblastoma as a distinct clinicopathologic entity has long been debated but is recognized in the 2007 WHO classification of CNS tumors. The grading of these tumors remains unsettled. Currently, no grade has been established and there are no clearly defined diagnostic criteria for low- or high-grade tumors. Astroblastomas in general are thought to have a favorable outcome with low rates of recurrence following gross total resection. We report a case of astroblastoma with 'high-grade/anaplastic' histology in a 12-year-old, previously healthy girl. The patient experienced severe, sudden-onset headache, and quickly became comatose. Head CT showed a massive intraparenchymal hemorrhage in the right frontal lobe with surrounding edema. She underwent emergent posterior frontal craniotomy for decompression and hematoma evacuation. Pathologic examination revealed a sharply demarcated hemorrhagic heterogeneous glial tumor with focal papillary architecture, densely hyalinized blood vessels, and intensely GFAP-positive perivascular cells. The tumor showed unequivocal high-grade features including an elevated proliferative index. The diagnosis of anaplastic astroblastoma was rendered. The patient expired on postoperative day 30. This case illustrates the potential poor outcome of high-grade astroblastoma and highlights the morphologic heterogeneity of this rare neoplasm.

Molecular neuropathology of low-grade gliomas and its clinical impact

The term "low-grade glioma" refers to a heterogeneous group of slowly growing glial tumors corresponding histologically to World Health Organization (WHO) grade I or II. This group includes astrocytic, oligodendroglial, oligoastrocytic and ependymal tumor entities, most of which preferentially manifest in children and young adults. Depending on histological type and WHO grade, growth patterns of low-grade gliomas are quite variable, with some tumors diffusely infiltrating the surrounding central nervous system tissue and others showing well demarcated growth. Furthermore, some entities tend to recur and show spontaneous malignant progression while others remain stable for many years. This review provides a condensed overview concerning the molecular genetics of different glioma entities subsumed under the umbrella of low-grade glioma. For a better understanding the cardinal epidemiological, histological and immunohistochemical features of each entity are shortly outlined. Multiple cytogenetic, chromosomal and genetic alterations have been identified in low-grade gliomas to date, with distinct genetic patterns being associated with the individual tumor subtypes. Some of these molecular alterations may serve as a diagnostic adjunct for tumor classification in cases with ambiguous histological features. However, to date only few molecular changes have been associated with clinical outcome, such as the combined losses of chromosome arms 1p and 19q as a favorable prognostic marker in patients with oligodendroglial tumors.

A 33-year-old Chinese woman with a left frontal tumor

Rhabdoid tumor cells are typically observed in atypical teratoid/rhabdoid tumor (AT/RT) but may also be seen in meningioma,glioma, melanoma, rhabdomyosarcoma and metastatic carcinoma.We present an astroblastoma with unusual rhabdoid features which is rarely described in the English literature. Apart from the rhabdoid tumor cells, all the histopathological features typical for astroblastoma are present in this case. These features include pseudopapillary arrangement, astroblastic pseudorosettes, perivascular hyalinization and calcifications, absence of fibrillary background and a pushing tumor border. The tumor cells display a multilineage immunohistochemical profile. In addition, diffuse and strong membranous and cytoplasmic dot-like pattern is appreciated with epithelial membrane antigen (EMA). The diagnosis of astroblastoma is also well supported by the age of presentation, anatomical location and radiological features of the tumor.We believe that on top of the above-mentioned unusual tumors with rhabdoid cells, astroblastoma should also be considered in the list of differential diagnosis.

A Cerebral Astroblastoma Mimicking an Extra-axial Neoplasm

Astroblastoma is a rarely diagnosed primary brain neoplasm whose histogenesis has been clarified recently. It occurs in children and young adults and presents as a well circumscribed, contrast-enhancing lesion in the cerebral hemisphere. We present a case of 20-year-old woman with an astroblastoma in the left temporal convexity that was treated with total tumor resection alone. We thought the mass was extra-axial neoplasm based on radiological findings of computed tomography and magnetic resonance imaging initially, but later, we obtained angiographic findings suggesting an intra-axial neoplasm. The patient is doing well even two years after surgery. The characteristic radiological and histopathological features of this case are described with a literature review. An astroblastoma should be included in the differential diagnosis of a superficially located tumor presenting with the findings of an extra-axial mass, especially in a young patient.

Consecutive histological changes in an astroblastoma that disseminated to the spinal cord after repeated intracranial recurrences: a case report

A 17-year-old male patient underwent surgery five times (four consecutive intracranial tumor removal surgeries and a final spinal tumor removal surgery). After the third surgery, this case was reported as a low-grade astroblastoma that is characterized by perivascular pseudorosettes consisting of elongated tumor cells arranged around the blood vessels. However, the fourth and fifth surgical specimens demonstrated very interesting histological changes in the astroblastoma. Through the course of relapses, the constituent cells of the astroblastic perivascular rosettes became smaller and rounder, and a multilayered cell arrangement was observed. The nucleus-to-cytoplasm ratio increased, and the compact intervascular cells ultimately lost glial fibrillary acidic protein (GFAP) expression. These undifferentiated cells showed high MIB-1 indices and an increased olig2 index. On the other hand, the cells in all the surgical specimens were positive for certain neuronal markers such as NSE, TUJ1, and nestin. Some astroblastomas may be more immature than the usual astrocytes; however, it is necessary to study more cases to confirm this.

Astroblastoma in a child

BACKGROUND

Astroblastoma, an uncommon neuroepithelial tumor, typically presents in young adults as a well-circumscribed cortical or subcortical spherical mass. Astroblastoma may cause a diagnostic problem to anyone unfamiliar with its architectural and histological features.

CASE HISTORY

We report the case of a 4-year-old boy who was referred for complaints of progressive deficits of balance and difficulty with walking during the previous 3 months. A large fronto-parietal cystic mass with solid mural nodule was discovered. Total removal of the tumor mass was performed, and a diagnosis of high grade (malignant) variant of astroblastoma was made. Postoperatively, the patient received radiation therapy, for a period of 11 weeks, followed by chemotherapy. He is in a good neurological recovery without any evidence of recurrence for 8 months.

PROGNOSIS

The best treatment modality for astroblastoma is surgical resection if possible, whereas adjuvant therapy (radiotherapy and/or chemotherapy) can be considered in high-grade astroblastomas, with a close follow-up for all cases.

Intraventricular astroblastoma. Case report

Astroblastoma is a rare primary brain neoplasm that accounts for 0.45-2.8% of brain gliomas. Intraventricular localization is extremely rare. The authors report a case of well-differentiated completely intraventricular astroblastoma in a 6-year-old girl and review the relevant literature. Their patient presented with a 5-week history of progressive nausea and vomiting. Magnetic resonance (MR) imaging revealed a large, well-demarcated, solid-cystic mass in the left temporooccipital ventricular horn. Macroscopic radical resection of the tumor was performed via the superior temporal sulcus. The postoperative course was uneventful and no adjuvant therapy was administered after surgery. No recurrence was detected at 9-months follow-up. Gross-total resection has the greatest impact on patient survival. In differentiated tumors, recurrence is usually local, and adjuvant therapy is recommended after repeated resection for the treatment of recurrence. In patients harboring anaplastic astroblastoma, gross-total resection and adjuvant therapy after the initial surgery seems to be the best choice. It is important to distinguish astroblastoma from ependymoma in clinical practice because of the differences in therapeutic approaches.

Brainstem astroblastoma: a case report and review of the literature

BACKGROUND

Astroblastoma is a rare glial tumor that occurs mainly in the cerebral hemispheres of young adults. Our purpose in writing this article is to report one case of astroblastoma located within the medulla and review the literature on this infrequent tumor.

METHODS

One case of astroblastoma was retrospectively reviewed. Presenting complaints, radiographic images, operative procedure, and histopathologic findings were recorded.

RESULTS

Contrast-enhanced MRI scan revealed a well-defined, well-circumscribed, contrast-enhanced cystic lesion approximately 16 mm in diameter within the medulla oblongata. Light microscopy demonstrated a papillary neoplasm composed of mildly pleomorphic cells with indistinct cytoplasmic borders. The nuclei were generally round to oval in shape. Occasional rosettes of tumor cells were seen around blood vessels. Mitoses were not seen within the submitted specimen. One small area of necrosis was present. The tumor exhibited thickened but not hyalinized blood vessel walls. The tumor cells exhibited strong staining for EMA and vimentin throughout the tissue section. Neurofilament, CAM 5.2, and CK immunostains were negative, except for rare positive staining of CK between cells and within rare tumor cells. Ki-67 was positive in small numbers of tumor nuclei, with an overall reactivity of 7%. By electron microscopy, the tumor nuclei had irregularly round to oval nuclei with moderate clumping of the chromatin, especially at the nuclear margins.

CONCLUSIONS

The combination of the radiologic and histopathologic characteristics of this tumor is necessary for making the diagnosis of astroblastoma. This article serves to summarize these characteristics as well as to report of an unusual location for this mainly hemispheric tumor.

AN ASTROBLASTOMA MIMICKING A CAVERNOUS MALFORMATION

OBJECTIVE

Astroblastomas are rare glial neoplasms that usually occur in young adults and have a predilection for the cerebral hemispheres. Patients typically present with signs of increased intracranial pressure and seizures. Imaging studies reveal circumscribed, contrast-enhancing tumors that contain both cystic and solid components with variable peritumoral edema. Hemorrhage, which suggested the presence of a vascular lesion in this patient, has not been previously described as a feature of this neoplasm.

CLINICAL PRESENTATION

The authors report the case of a 33-year-old woman who presented with spontaneous intraparenchymal hemorrhage. The collective radiographic data suggested the presence of a cavernous malformation.

INTERVENTION

A right frontotemporal craniotomy was performed under frameless stereotactic image guidance. An astroblastoma was diagnosed after resection and neuropathological examination.

CONCLUSION

A rare radiological to pathological correlation of astroblastoma is presented in which the evolving hematoma, as observed on magnetic resonance imaging scans, complicated the radiographic diagnosis of this lesion. The clinical, radiographic, and pathological features of astroblastomas, as well as the natural history of these rare glial neoplasms, are reviewed. This case illustrates the capacity of astroblastomas to hemorrhage, disguising the classic radiographic findings typical of this glial neoplasm.

Astroblastoma presenting with intracerebral hemorrhage misdiagnosed as dural arteriovenous fistula: review of a rare entity

BACKGROUND

Astroblastoma is one of the most unusual types of tumors whose histogenesis has been recently clarified. It occurs mainly among children and young adults. It is grossly well demarcated and shows histologically characteristic perivascular pseudorosettes with frequent vascular hyalinization. Immunohistochemically, the tumor cells show diffuse strong positivity for GFAP, S-100 protein, vimentin, as well as neuron-specific enolase and focal positivity for EMA.

CASE DESCRIPTION

Our patient is a 33-year-old gentleman who presented with intraparenchymal hemorrhage in the left temporal lobe. A 4-vessel cerebral angiogram revealed a dural AVF in the left posterior temporal area. The lesion was resected, and pathology showed a GFAP-positive lesion with prominent astroblastoma rosettes. There was abundant hemosiderin consistent with a prior hemorrhage. Because of its high degree of proliferation, the presence of astroblastic pseudorosettes, prominent perivascular hyalinization, regional hyaline changes, and pushing borders with regard to the adjacent brain, the tumor was considered anaplastic.

CONCLUSIONS

Astroblastoma is a rare pure pathologic entity--a distinct form of astrocytic gliomas. The diagnosis of astroblastoma is often difficult because of the astroblastic aspects that can be found in astrocytic tumors, in ependymomas, and in nonneuroepithelial tumors. The natural history seems to be between astrocytomas and glioblastomas. Total resection and radiation therapy seem to be the advisable treatments.

An astroblastoma case associated with loss of heterozygosity on chromosome 9p

The tumorigenesis of astroblastomas has not yet been elucidated on the basis of histopathological studies, and genetic studies may be useful for obtaining additional information regarding the tumorigenesis of these tumors. Here, we report an astroblastoma case in which a genetic analysis was performed. A 16-year-old female with a progressive headache was found to have a demarcated cystic tumor with a mural nodule in the right parietal lobe. Total removal of the tumor was achieved and a histological examination verified that the tumor was an astroblastoma. A genetic analysis using microsatellite markers revealed loss of heterozygosity (LOH) on chromosome 9p. The postoperative course was uneventful and, to date, she has been followed up for 2 years with no signs of recurrence. This is the first reported case of an astroblastoma in which LOH was detected on 9p. Based on this result, the tumorigenesis of astroblastomas is discussed.

Astroblastoma: immunohistochemical and ultrastructural study of distinctive epithelial and probable tanycytic differentiation

We report the clinicopathological findings of astroblastoma found in an 8-year-old girl who was subsequently treated for 11 years. The primary superficially circumscribed tumor was located in the frontoparietal lobe, while the recurrent and the second recurrent tumor were restricted to the same region 11 years later. The tumors obtained on these three occasions showed fundamentally the same histological, immunohistochemical and fine structural features. They exhibited astrocytic as well as ependymal tanycytic features with apparent epithelial cell lineage. The tumor cells showed typical features of astroblastoma comprising prominent perivascular pseudorosettes with remarkable vascular sclerosis. The immunohistochemical study revealed intensive positivity of GFAP, vimentin, epithelial membrane antigen (EMA), cytokeratin, connexin 26 and 32, desmocollin 1 and neuronal cadherin. The fine structure revealed divergent types of junctional complexes, some of which were connected with tonofilament bundles. Numerous microvilli protruded and basal lamina abutted on the tumor cell surface. We report these unique histological features, and stress that astroblastoma should be categorized as a specific type of neuroepithelial tumor.

Complete surgical resection of high-grade astroblastoma with long time survival: case report and review of the literature

Astroblastoma is a rare glial neoplasm of unknown origin and uncertain prognosis. It usually presents in young adults as a well circumscribed hemispheric mass, often associated with a cystic component. The histological features of astroblastoma are the presence of typical astroblastic perivascular pseudorosettes and perivascular hyalinization. Two different subtypes of astroblastoma have been defined based upon histological characteristics. Prognosis, however, sometimes is in contradiction with the pathological appearance and seems to be more closely related to the grade of surgical resection. We present a new case of a patient with a high-grade astroblastoma with a long survival time, in whom complete surgical resection was confirmed by an early postoperative MRI.

Molecular cytogenetic analysis in the study of brain tumors: findings and applications

Classic cytogenetics has evolved from black and white to technicolor images of chromosomes as a result of advances in fluorescence in situ hybridization (FISH) techniques, and is now called molecular cytogenetics. Improvements in the quality and diversity of probes suitable for FISH, coupled with advances in computerized image analysis, now permit the genome or tissue of interest to be analyzed in detail on a glass slide. It is evident that the growing list of options for cytogenetic analysis has improved the understanding of chromosomal changes in disease initiation, progression, and response to treatment. The contributions of classic and molecular cytogenetics to the study of brain tumors have provided scientists and clinicians alike with new avenues for investigation. In this review the authors summarize the contributions of molecular cytogenetics to the study of brain tumors, encompassing the findings of classic cytogenetics, interphase- and metaphase-based FISH studies, spectral karyotyping, and metaphase- and array-based comparative genomic hybridization. In addition, this review also details the role of molecular cytogenetic techniques in other aspects of understanding the pathogenesis of brain tumors, including xenograft, cancer stem cell, and telomere length studies.

Monomorphous Angiocentric Glioma: A Distinctive Epileptogenic Neoplasm With Features of Infiltrating Astrocytoma and Ependymoma

We present 8 examples of a neoplasm with features of both astrocytoma and ependymoma that may represent a distinct clinicopathologic entity. The cerebral hemispheric tumors occurred in patients that were 3, 4, 12, 14, 15, 26, 30, and 37 years of age. All presented with seizures that, with the exception of 2, began in childhood. Magnetic resonance imaging studies showed ill-defined, T2-hyperintense, generally noncontrast-enhancing lesions that, although centered on the cortex or amygdala, extended into the underlying white matter for a short distance. Histologically, the variably infiltrative tumors were distinctively angiocentric with well-developed perivascular pseudorosettes in some cases. Longitudinal and/or circumferential orientations of perivascular cells were common also. The cells were uniform in their cytologic features from case to case and were bipolar in all but one case. A glial nature was inferred from immunoreactivity for GFAP, and ependymal differentiation was suggested by positivity for EMA in three cases and ultrastructural features in one. Overall, the tumors were biologically indolent except for one that recurred and ultimately proved fatal.

Astroblastoma in childhood: pathological and clinical analysis

OBJECT

The object was to describe the clinical, radiologic, and pathologic features of astroblastomas in an unselected group of children who were treated in a single institution during an 11-year period.

METHODS

Eight children with astroblastomas of the brain were examined. Diagnosis was based on cell morphology, vascular attachment of the cell main process, lack of an epithelial-free surface differentiation, and poor intercellular cohesiveness. In addition to sections, tumor smears and electron microscopy were required for demonstrating or confirming such features.

CONCLUSIONS

Clinical findings seem to confirm an apparent predilection of astroblastomas for younger children (median age of onset, 5 years) and the existence of two prognostically different types of tumor-well differentiated (low grade) and anaplastic (high grade). Microscopic findings suggest a closer resemblance of tumor cells to astroblasts rather than to "tanycytes" or ependymal cells. It seems, however, that anaplastic astroblasts have a tendency to evolve toward, or be associated with, less differentiated cells, either neuroepithelial or sarcomatous.

Supratentorial extraventricular ependymal neoplasms

BACKGROUND

Published research on the clinicopathologic features of extraventricular ependymal neoplasms of the cerebral hemispheres has been scant.

METHODS

Thirty-two archival cases were studied to investigate the prognostic impact of clinicopathologic parameters including flow cytometry, the proliferation (Ki-67) labeling index, and p53 expression.

RESULTS

Among these 32 cases were 2 subependymomas, 19 ependymomas, and 11 anaplastic ependymomas. No significant gender predilection was observed, and 45% of patients were in their second or third decade of life. The left cerebral hemisphere was 1.5 times more commonly involved. On available imaging studies, lesions were often cystic, with or without a mural nodule. Tumors expressed glial fibrillary acidic protein (87%), S-100 protein (77%), cytokeratin (43%), and epithelial membrane antigen (17%). Ki-67 proliferation index paralleled tumor grade. Immunoreactivity for p53 protein was observed in the 2 cases of subependymoma, in 10 of 11 anaplastic ependymomas, and in 6 of 17 ependymomas. Flow cytometry performed in 27 tumors revealed diploidy in 20 cases and aneuploidy in 4 cases (3 anaplastic and 1 classic ependymomas), with S-phase fraction ranging from 0.2-9.7. Eleven subjects were additionally treated with radiotherapy, and 3 with chemotherapy. Follow up was available in 25 (78%) patients.

CONCLUSIONS

The results of the current study suggest that there is no significant relation between histopathology, Ki-67 proliferation index, p53 immunolabeling, tumor ploidy, and biologic behavior.

Prognosis-related histomorphological and immunohistochemical markers in central nervous system tumors of childhood and adolescence

Brain tumors account for approximately 20% of all childhood cancers, and are the leading cause of cancer morbidity and mortality among children. Although numerous demographic, clinical and therapeutic parameters have been identified over the past few years that have significant prognostic bearing for some pediatric brain tumors, predicting the clinical course and outcome among children with central nervous system tumors is still difficult. A survey of publications on prognosis-related histopathological and immunohistochemical features among pediatric brain tumors revealed 172 series, of which 91 presented statistically significant outcome-associated parameters as defined by a P value of less than 0.05. Most investigations revealing significant prognosis-related markers were performed on medulloblastomas (30 publications), ependymomas (25) and astrocytic tumors (18). In total, 16 cohorts consisted of more than 100 cases (5 on ependymomas, 3 each on medulloblastomas and astrocytic tumors). On the other hand, there were also 13 series with fewer than 20 cases (5 on medulloblastomas). Potentially prognostic histopathological markers vary among different entities and consist of assessment of necroses, mitoses, differentiation, vascular proliferation, and growth pattern, whereas immunohistochemical features include proliferation markers (Ki-67, MIB-1), expression of oncogenes/tumor suppressor genes and their proteins (TP53, c-erbB2), growth factor and hormonal receptors (VEGF, EGFR, HER2, HER4, ErbB-2), cell cycle genes (p27, p14ARF) and cell adhesion molecules, as well as factors potentially related to therapeutic resistance (DNA topoisomerase IIalpha, metallothionein, P-glycoprotein, tenascin). This review discusses the prognostic potential of histopathological and immunohistochemical markers that can be investigated by the practicing neuropathologist as part of the routine diagnostic workload, and scrutinizes their benefit for predicting therapy response and patient outcome among children with brain tumors.

Astroblastoma: a case report

Astroblastoma is one of the very unusual type of tumors, whose histogenesis has not been clarified. It occurs mainly among children or young adults. Astroblastoma is grossly well-demarcated, and shows histologically characteristic perivascular pseudorosettes with frequent vascular hyalinization. Perivascular pseudorosettes in astroblastoma have short and thick cytoplasmic processes and blunt-ended foot plates. A 15-yr-old girl presented with headache and diplopia for one and a half year. A well-demarcated mass, 9.7 cm in diameter, was found in the right frontal lobe in brain MRI, and it was a well-enhanced inhomogenous mass. Cystic changes of various sizes were observed inside the tumor mass as well as in the posterior part of the mass, but no peritumoral edema was found. Histologically, this mass belongs to a typical astroblastoma, and no sign of anaplastic astrocytoma, gemistocytic astrocytoma or glioblastoma was found in any part of the tumor. Immunohistochemically, the tumor cells showed diffuse strong positivity for glial fibrillary acidic protein, S-100 protein, vimentin and neuron specific enolase, and focal positivity for epithelial membrane antigen and CAM 5.2, while showing negativity for synaptophysin, neurofilament protein, pan-cytokeratin and high molecular weight keratin.

Comparative Genomic Hybridization in Central and Peripheral Nervous System Tumors of Childhood and Adolescence

Brain tumors amount to less than 2% of all malignant neoplasms. However, they account for approximately 20% of all childhood cancers and are the leading cause of cancer mortality among children. Recently, enormous progress has been achieved in the field of pediatric neuro-oncology regarding the classification of children's brain tumors, as well as the understanding of the genetic events involved in their pathogenesis; thus leading to an emerging role of molecular diagnostic approaches using novel tools. Comparative genomic hybridization (CGH) is a technique that has revolutionized cytogenetic knowledge in the past decade. It permits the detection of chromosomal copy number changes without the need for cell culturing and gives a global overview of chromosomal gains and losses throughout the whole genome of a tumor. A survey of CGH-related publications on central and peripheral nervous system tumors in the pediatric and adolescent population revealed 884 cases. The CNS tumor groups most frequently examined by CGH were embryonal tumors (268 cases/30.3%) and ependymomas (241/27.2%), followed by astrocytic (163/18.4%), peripheral nerve (73/8.2%), choroid plexus tumors (56/6.3%), and craniopharyngiomas (38/4.3%). The most common CNS tumor entities were medulloblastomas (238/26.9%), classic ependymomas (160/18.1%), anaplastic ependymomas (70/7.9%), pleomorphic xanthoastrocytomas (53/6.0%), and pilocytic astrocytomas (50/5.6%). This article provides a short review of the CGH technique and its pitfalls, summarizes the current CGH-related data on pediatric brain tumors and muses on the future of CGH.

[Cerebral astroblastoma: report of a case and literature review]

We report a new case of low grade astroblastoma of pure type and consider the definition and the clinical, neuroimaging, intraoperative and pathological characteristics of this type of uncommon intracranial tumour. We analyse the differences found in the literature concerning the immunochemistry, genetics and electron microscopy. We point out the lack of protocols for treatment of this type of intracranial tumour, and comment the various hypothesis of its origin.

Astroblastoma with unusual signet-ring-like cell components: a case report and literature review

We report a case of astroblastoma with unusual signet-ring-like cell components. A 33-year-old-woman presented with occasional partial seizures of the face. Radiological studies revealed an enhanced frontal mass lesion. At surgery, a gray, soft, well-circumscribed mass was seen and shelled out. Histologically, the tumor showed a perivascular arrangement and papillary-like patterns with compact cellularity. The tumor cells radiating from the hyalinized vessels showed broader, shorter, less tapered processes. A part of each tumor cell displayed prominent islands of signet-ring-like cells. Glial fibrillary acidic protein reaction revealed strongly positive staining of tumor cells and signet-ring-like cells. Eight years after the operation the patient remains well with no tumor recurrence. It remains to be determined whether, in this astroblastoma, the unusual signet-ring-like cell components were related to benign biological characteristics or to the tumor's low-grade form with incidental signet-ring-like cell appearance.

Compilation of published comparative genomic hybridization studies

The power of comparative genomic hybridization (CGH) has been clearly proven since the first paper appeared in 1992 as a tool to characterize chromosomal imbalances in neoplasias. This review summarizes the chromosomal imbalances detected by CGH in solid tumors and in hemopathies. In May of 2001, we took a census of 430 articles providing information on 11,984 cases of human solid tumors or hematologic malignancies. Comparative generic hybridization has detected a number of recurrent regions of amplification or deletion that allows for identification of new chromosomal loci (oncogenes, tumor suppressor genes, or other genes) involved in the development, progression, and clonal evolution of tumors. When CGH data from different studies are combined, a pattern of nonrandom genetic aberrations appears. As expected, some of these gains and losses are common to different types of pathologies, while others are more tumor-specific.

Astroblastoma: radiologic-pathologic correlation and distinction from ependymoma

SUMMARY

Astroblastoma is a rare primary glial tumor with a characteristic appearance on neuroradiologic images. Typically, astroblastomas are large, lobulated, peripheral, supratentorial, solid, and cystic masses with relatively little associated vasogenic edema and tumor infiltration for their large size. The solid component of the mass has a bubbly appearance and a T2 signal that is isointense to gray matter. Punctate calcifications are often present. Neuroradiologists should be familiar with the characteristic appearance of this tumor.