Genetic evidence of the neoplastic nature of gemistocytes in astrocytomas

Gemistocytic astrocytoma is characterized by a predominance of large astrocytes with plump processes and massive accumulation of glial fibrillary acidic protein (gemistocytes). This histological variant of low-grade diffuse astrocytoma (WHO grade II) is prone to more rapid progression to anaplastic astrocytoma and glioblastoma than the ordinary fibrillary astrocytoma. The biological basis of this unfavorable prognosis is unclear, since gemistocytes themselves have low proliferative activity, even if present in anaplastic astrocytomas or glioblastomas. This has raised the question of whether gemistocytes are neoplastic cells or dysplastic reactive astrocytes. In this study, gemistocytes and non-gemistocytic neoplastic cells were separated by laser-assisted microdissection from six gemistocytic astrocytomas carrying TP53 mutations. In all cases, identical TP53 mutations were identified in both cell types, indicating that gemistocytes are indeed neoplastic cells. Their lack of proliferative activity may indicate terminal differentiation.     

Frequency of surface microprojections and coated vesicles with increased malignancy in human astrocytic neoplasms

Summary Surface membrane microprojections and coated vesicles of a well differentiated (Kernohan-Sayre grade I) cerebral fibrillary astrocytoma were compared with those of anaplastic astrocytic (grade IV, glioblastoma) cerebral tumors. Both phenomena increase with increased malignancy. This provides further evidence for membrane alterations with malignant change in human astrocytic cells. It is the first comparison of fibrillary astrocytoma surface phenomena with those of more malignant astrocytic tumors of the cerebrum.     

Distinctive multicystic hemispheric lesions suggesting a novel variant of infantile astrocytoma

Two unrelated female infants presented at 9 days and 2 months, respectively, with apneic episodes in the former and gaze preference in the latter. MRI revealed enlargement of almost the entire right hemisphere, apparently smooth cortex, simplification of the gyral pattern, and expanded white matter with abnormal signal intensity containing multiple intraparenchymal cysts. Histologic examination of both cases revealed white matter infiltration by a hypocellular lesion composed of uniform, fibrillary astrocytes in a microcystic background. Multilocular tumor cysts were prominent, but Rosenthal fibers and eosinophilic granular bodies were absent. Very rare mitoses were seen in the absence of necrosis or vascular change. There was no convincing cortical infiltration, but the subpial zone was diffusely expanded by a band of astrocytes set in a dense fibrillar feltwork which opened out into numerous cystic spaces. No desmoplastic changes or associated atypical ganglion cells were identified. There was no evidence for a BRAFKIAA1549 fusion or BRAF mutation in one case tested. In conclusion, both lesions are not desmoplastic infantile astrocytoma/ganglioglioma, fibrillary astrocytoma, or typical for pilocytic astrocytoma. Such extreme subpial spread with cysts is most unusual and may suggest a novel variant of infantile astrocytoma.     

Immunohistochemical study of S-phase cells in human gliomas

Intermediate filament proteins are cytoskeletal components in most vertebrate eukaryotic cells and some of these proteins are recognized markers of cell differentiation. To investigate the expression of intermediate filament proteins of the S-phase cells in human glial tumors, we have examined fourteen patients with benign and malignant gliomas by immunohistochemical study using in vivo labeling with bromodeoxyuridine (BrdU). Five glioblastoma multiforme, five anaplastic astrocytoma, three fibrillary astrocytoma and one gemistocytic astrocytoma were studied. All patients were given intravenous infusion of BrdU (10 mg/kg) one hour before craniotomy for labeling the S-phase cells of the tumors. Surgical specimens were immersed in 70% ethanol, and embedded in paraffin. Four micron sections were immunostained with anti-BrdU monoclonal antibody (Mab) and anti-vimentin Mab by avidin-biotin complex (ABC) method, and anti-glial fibrillary acidic protein (GFAP) serum by peroxidase-antiperoxidase (PAP) method. All sections (except for case 4) were double-labeled with anti-BrdU Mab and anti-GFAP serum, or with anti-BrdU Mab and anti-vimentin Mab. The population of BrdU-labeled cells (i.e. S-phase cells), and double-labeled cells were analyzed. The proportions of BrdU-labeled cells ranged from 6.1% to 17.0% (average 11.1%) in glioblastoma multiforme, from 3.5% to 15.6% (average 8.8%) in anaplastic astrocytoma, and from 2.0% to 2.8% (average 2.5%) in fibrillary astrocytomas. One gemistocytic astrocytoma showed S-phase fraction of 1.7%. Two recurrent cases of anaplastic astrocytoma showed higher S-phase fractions than other non-recurrent cases of anaplastic astrocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mistaken identity: Granular cell astrocytoma masquerading as histiocytosis of the central nervous system

Granular cell astrocytoma (GCA) is an uncommon malignant glial tumour that is associated with a poor prognosis. GCA cells have some morphological and immunohistochemical similarities to macrophages. In this case, a small biopsy contained no typical astrocytoma and large rounded lesional cells were interpreted as negative for glial fibrillary acidic protein and S100 and positive for CD68, a commonly used marker for macrophages. A diagnosis of a histiocytosis was made. When the patient failed to respond to first and second line therapy, tumour resection was undertaken and the pathology then showed typical morphologic and immunohistochemical features of glioblastoma (astrocytoma World Health Organization grade IV).     

Glial fibrillary acidic protein (GFAP): purification from human fibrillary astrocytoma, development and validation of a radioimmunoassay for GFAP-like immunoactivity.

The extraction and purification of glial fibrillary acidic protein (GFAP) from human fibrillary cerebellar astrocytoma is described. Using an immunoperoxidase method, antisera raised to the protein showed specific staining of astrocytes in normal spinal cord and in tumours of astrocytic origin. A double antibody radioimmunoassay for GFAP in tissue extract was developed, the detection limit of the assay being 360 pg. Extracts of tissues other than brain or spinal cord did not cross-react significantly in the assay, neither did purified preparations of myelin basic and S-100 proteins. Levels of GFAP in normal CNS tissue were higest in spinal cord (1370 microgram/g wet weight) but a level of 3050 microgram/g wet weight was detected in a fibrillary astrocytoma.     

Peculiar changes in Rosenthal fibres in an atypical astrocytoma

A 50-year-old female patient died of an untreatable glioma apoplecticum. At autopsy a strongly vascularized glial tumour was found. The criteria for malignancy according to the WHO classification were only partially fulfilled by this tumour which displayed morphological features of an astrocytoma but could not be further subclassified. By light microscopy, angioma-like vascular proliferations, large cells with brightly eosinophilic cytoplasm, and small cells with hyperchromatic nuclei were found. Most large cells had vesicular, excentrically placed nuclei and contained fibrillary whorls or amorphous, irregular cytoplasmic inclusions. By immunohistochemical staining, using antibodies to glial fibrillary acidic protein (GFAP) the fibrillary whorls were identified as aggregates of glial filaments. The amorphous inclusions lacked GFAP immunoreactivity and appeared in the electron microscope as electron dense material surrounded by a dense network of glial filaments. The abnormal perikaryal inclusions of these atypical astrocytoma cells appeared to be peculiar alterations of Rosenthal fibres closely mimicing Mallory bodies.     

Heterologous transplantation of cerebral and cerebellar astrocytomas

Summary Twenty two cases of cerebral and so-called cerebellar astrocytomas were heterologously transplanted to guinea pigs. Although the fifteen cerebral astrocytomas were selected according to optimal conditions for transplantation, all failed to grow heterologously. The cerebral astrocytomas represent varieties of fibrillary, protoplasmic and pilocytic types, and all originated in adults. Of the seven randomly selected so-called cerebellar astrocytomas, all of which occurred in children, only one grew when transplanted intracerebrally to guinea pigs. This tumor before transplantation had all the histological characteristics of a so-called cerebellar astrocytoma. The prevailing cells were elongated, spongioblast-like elements; however, other cell types, e.g., astrocytes occurred in varying numbers. The heterotransplant was dominated by elongated, mostly bipolar cells with a very characteristic cytoarchitectural arrangement. The controversy regarding classification of cerebellar astrocytomas versus cerebellar spongioblastomas was discussed. Although the name spongioblastoma is not favored, the concept of classifying the so-called cerebellar astrocytoma together with other slow growing midline gliomas as proposed by Zülch has definite merits. Heterotransplantation studies clearly demonstrate that the so-called cerebellar astrocytoma has different biological properties than cerebral astrocytomas.Supported by United States Public Health Service Research Grant No. NB-07849-04.     

Age-dependent rate of anaplastic transformation in low-grade astrocytoma

Age and histologic grade are interrelated characteristics of diffuse fibrillary astrocytomas, because the peak age incidence rises with increasing grade. The relationship between age and grade may be explained if age determines the rate of anaplastic progression in astrocytomas. The authors tested this hypothesis by determining the interval between diagnosis of low-grade astrocytoma and progression to high-grade astrocytoma in patients of various ages. A two-way scatterplot of age at initial diagnosis versus interval to anaplastic progression demonstrated a strong negative correlation (n = 24; Pearson correlation coefficient = -0.83; Spearman correlation coefficient = -0.79; p < 0.001 for both values). It was concluded that the rate of anaplastic progression in low-grade astrocytoma is directly correlated with patient age.     

Gliosarcoma arising from a fibrillary astrocytoma

We report a 67-year-old woman who was diagnosed with a gliosarcoma at a second operation after diagnosis of a fibrillary astrocytoma 5 months previously. Initially, she underwent a CT-guided stereotactic biopsy. Histological examination showed fibrillary astrocytoma (World Health Organization [WHO] grade II). Loss of heterozygosity (LOH) on 1p, 10q, and 19q was not detected. She received chemotherapy, but no radiotherapy. Five months after the biopsy, MRI revealed rapid tumor growth. Tissue obtained from partial removal of the tumor revealed gliosarcoma (WHO grade IV), and LOH on 10q and 19q was detected. The history, histopathology, and genetic alterations of this patient are discussed.     

p16(ink4a) and retinoic acid modulate rhoA and GFAP expression during induction of a stellate phenotype in U343 MG-A astrocytoma cells

We previously showed that the expression of p16(ink4a) (p16), in conjunction with retinoic acid (RA) treatment in the p16-deficient astrocytoma cell line, U343 MG-A, induced a potent cell cycle arrest in G(1) associated with changes in morphology. In this study, we investigated the effects of p16 expression and RA treatment on the expression and distribution of actin, glial fibrillary acidic protein (GFAP), and vimentin within the U343 MG-A astrocytoma cytoskeleton. Changes in expression and location of the small GTPase, rhoA, were also examined after p16 expression and RA treatment. We showed that p16 expression and RA treatment led to an increase in the expression of GFAP, as well as its reorganization but that it did not significantly affect actin or vimentin expression. p16 induction in combination with RA treatment resulted in a decreased expression and activation of rhoA as determined by immunocytochemistry and Western blot analysis of soluble and insoluble fractions of cell lysates. Endogenous levels of rhoA expression varied among samples in a panel of astrocytoma cell lines as determined by Western blot analysis. Introduction of a dominant active rhoA mutant into p16-induced, RA-treated U343 MG-A astrocytoma cells was associated with the loss of long astrocytic processes and stellate morphology. These data are among the first to report the pattern of rhoA expression in human astrocytoma cell lines. They furthermore suggest that the stellate cell phenotype observed in U343 MG-A astrocytoma cells after cyclin-dependent kinase inhibitor (CKI) induction and RA treatment is accompanied by an inhibition and inactivation of rhoA in this cell system.     

Cerebellar astrocytomas: a 24-year experience

INTRODUCTION: Cerebellar astrocytomas are the most benign tumors of the CNS. Seventy to eighty percent are found in children. METHODS AND RESULTS: We report on 38 children under 18 who had cerebellar astrocytoma in the posterior fossa and were treated by a multidisciplinary team in our Neurosurgical Department from January 1974 to December 1997. We included all patients in whom the histopathological diagnosis was astrocytoma, regardless of malignancy. The diagnostic methods used were pneumoventriculography, cranial X-rays, CT scan, and MRI. All patients were treated surgically. Neither radiotherapy nor chemotherapy was indicated in patients with pilocytic or fibrillary astrocytomas. A greater prevalence was observed in female (25/38; 66%) than in male (13/38; 34%) patients. Histopathological results revealed 27 (71%) pilocytic astrocytomas, 8 (21%) diffuse fibrillary astrocytomas, 1 (2%) anaplastic astrocytoma and 2 (6%) glioblastomas. These tumors were more frequently located in the right cerebellar hemisphere; increased intracranial pressure syndrome was the most frequent form of clinical presentation. Total tumor resection was obtained in 29 (83%) cases and subtotal resection in 9 (17%). In 6 (16%) cases, ventriculoperitoneal shunts were placed to control persistent hydrocephalus after tumor excision. CONCLUSION: The most frequent complication was increased ataxia. The mortality rate was 8.5%.     

Immunocytochemical and ultrastructural studies of eosinophilic granular bodies in astrocytic tumors

Summary Eosinophilic granular bodies (EGBs) are studied immunocytochemically and ultrastructurally in a case of low-grade and a case of high-grade astrocytoma. EGBs are recognized as brightly eosinophilic round bodies of variable size in hematoxylin and eosin-stained sections. Immunocytochemically some EGBs are positive for antibodies raised against B-crystallin, ubiquitin and glial fibrillary acidic protein with the staining patterns for each being different from one another. Ultrastructurally EGBs consist of membrane-bound round body of various diameter ranging from 50 nm to 20 m. Small EGBs contain electron-dense homogeneous material with occasional myelin figures, while large EGBs contain small EGB-like structures within electron-dense homogeneous material or loose granular profiles. Our studies demonstrate (1) ultrastructural variety of EGB; (2) and B-crystallin epitope in EGB; and (3) the presence of EGB in high-grade as well as low-grade astrocytoma.Supported in part by UPHS NS24453, HD03110, and ES01104     

Human malignant astrocytoma xenografts migrate in rat brain: a model for central nervous system cancer research

Fresh cells from two grade 3 human malignant astrocytomas were prelabeled with Phaseolus vulgaris leucoagglutin (PHAL) and then xenografted into freshly made implantation pockets in rat host cerebral cortex. Animals were sacrificed at 7, 14, 21 days, and 1 month postimplantation (DPI). Paraffin sections were double-labeled for the presence of glial fibrillary acidic protein (GFAP), a specific marker for astrocytes and differentiated astrocytoma cells, and PHAL, utilized as a marker for graft-derived cells. Grafted human astrocytoma cells were found on the glia limitans along the entire circumference of the brain, in the corpus callosum, internal capsule, entopeduncular nucleus, optic tract, and median eminence. In addition, astrocytoma cells were observed in the cingulum, habenula, arcuate, and supraoptic nucleus. Astrocytoma cells entered the spaces of Virchow-Robin, and migrated along parenchymal blood vessels and between the ependymal and subependymal layers of the third and lateral ventricles. The corpus callosum was a major migration route for the astrocytoma cells. The presence of basal lamina or parallel nerve fiber bundles was a common factor for these migration routes. The migration of the human astrocytoma xenografted cells in the rat brain followed the spread of human malignant astrocytomas in the human brain and is a valuable basic science tool in brain cancer research.     

Sub-classification of low-grade cerebellar astrocytoma: is it clinically meaningful?

OBJECTIVES: The objectives were to identify prognostic factors for the survival of children with cerebellar astrocytoma, and to evaluate the reproducibility and prognostic value of histological sub-classification and grading. METHODS: Children aged 0-14 years treated in Denmark for a cerebellar astrocytoma in the period 1960-1984 were included and followed until January 2001 or until their death. The histological specimens from each patient were reviewed for revised grading and classification according to three different classification schemes: the WHO, the Kernohan and the Daumas-Duport grading systems. RESULTS: The overall survival rate was 81% after a follow-up time of 15-40 years. The significant positive prognostic factors for survival were "surgically gross-total removal" of the tumour at surgery and location of the tumour in the cerebellum proper as opposed to location in the fourth ventricle. No difference in survival time was demonstrated when we compared pilocytic astrocytoma and fibrillary astrocytoma. Moreover, we found that the Kernohan and the WHO classification systems had no predictive value and that the Daumas-Duport system is unsuitable as a prognostic tool for low-grade posterior fossa astrocytomas. CONCLUSION: Discordant observations due to interobserver variability make histological sub-classification of low-grade cerebellar astrocytomas in children insufficient for predicting prognosis and biological behaviour. Similar survival rates in a population of paediatric low-grade cerebellar astrocytomas of grades I and II indicate that tumour grade has no prognostic significance within this group of patients. "Surgically gross-total removal", especially if the tumour is located in the fourth ventricle is of the highest importance for long-term survival. Histological sub-classification of the tumours has no predictive value.     

Tanycytic ependymoma arising from the right lateral ventricle: A case report and review of the literature

A 38‐year‐old man presented with a year‐long history of worsening headache. Neuroradiological findings showed that a solid cystic mass occupied the right lateral ventricle. Histologically, the tumor composed of nuclear dense zones consisting of a cluster of spindle cells and fibrillary zones consisting of streaming of cell processes. The tumor cells showed the characteristics of monopolar or bipolar processes. Some tumor cell processes extended to the vessel wall and formed ill‐defined perivascular rosettes. No mitoses or necrosis were found. The cells presented positive for GFAP, S‐100 protein, vimentin, Nestin and neurofilament, and dotlike positive for epithelial membrane antigen, but negative for Syn and NeuN. Four cases of tanycytic ependymoma arising from the lateral ventricle have been reported in literature. Histological differential diagnosis includes spindle‐shaped neuroepithelial tumors, such as pilocytic astrocytoma, fibrillary astrocytoma and schwannoma. Tanycytic ependymoma has slightly better prognosis than other ependymoma subtypes.     

Diagnosis of brain gliomas in stereotactic biopsy assisted by optical neuro-navigation system

BACKGROUND AND PURPOSE: Recently, stereotactic procedures of brain tumours have been enriched by an optical neuronavigation system, enabling us to assess the tumour location and size by means of three-dimensional magnetic resonance imaging (MRI). The aim of the study was to check which areas of brain gliomas would be most useful in neuropathological diagnosis of the material taken during stereotactic biopsy. We also analysed whether the MRI processed in the computerised neuronavigation system would be reliable in determination of a safety margin of glioma resection. MATERIAL AND METHODS: Material from the stereotactic biopsy has been examined neuropathologically by means of the Stealth Station navigation system. Tissue specimens were taken from the centre of neoplasm, its intermediate area, edge of the tumour and the nearest vicinity of neoplasm. 2-3 specimens in each area of the tumour were taken. The material was fixed in buffered formalin and embedded in paraffin and then stained with hematoxylin and immunostained for GFAP, cytokeratin and vimentin. RESULTS: Astrocytomas II were diagnosed in 17 cases, including fibrillary astrocytoma in 13 cases and gemistocytic astrocytoma in 2 cases. In other cases protoplasmatic astrocytomas were suspected. In 6 cases anaplastic astrocytoma and in 16 cases glioblastoma multiforme were diagnosed. In 3 cases the degree of malignancy was not possible to be defined. In 2 cases the neoplasm was not found. "Sensitivity" of the method was 91.1% and its "specificity" was 82.2%. The best results were achieved analysing the material from the intermediate area of neoplasm. There was the lowest number of "false negative" diagnostic results in this area. A few positive results were found in the central area and a high number of results (almost 50%) could be defined as "negative", assuming the specimens with no neoplastic cells. In more than 40% of biopsies from the edge of the tumour, neoplasm was not found, while in more than 20% of biopsies from the nearest vicinity of the tumour, neoplastic cells were present. CONCLUSIONS: Intermediate zone of brain gliomas located between its central parts and the tumour edge appears to be the most appropriate neoplastic area for diagnostic stereotactic biopsy assisted by the optical neuronavigation system. Because of infiltrative character of brain gliomas as well as their real dislocation during surgical procedure compared to the position based on the earlier neuroimaging, the territories considered in the optical neuronavigation system as the vicinity or neoplastic edge, run a risk of neuropathological misdiagnosis in this biopsy.     

AgNOR staining may reflect the growth potential of pilocytic astrocytomas

The value of AgNOR staining as a tumor biological marker was tested in 26 children with pilocytic astrocytomas (20) and fibrillary astrocytomas (6). All patients were surgically treated and then followed up by periodic MRI or CT scans. Follow-up ranged from 8 to 84 months, with a mean of 44 months. AgNOR expression was determined by using semi-automated computer-assisted surface area measurements. AgNOR values ranged from 1.4 to 81.4 μm² per cell, with a mean of 26.6 and a median of 15.2. The median value was taken as a ”cut-off” score separating two groups of patients with low and high AgNOR scores. Of the 13 patients in the low scoring group, 8 had total resections without recurrence, 3 had stable residual tumors, 1 had regressing residual tumor after irradiation and 1 had a recurrence 5 years after neuroradiologically complete resection of a fibrillary astrocytoma. In the group with high AgNOR scores only 2 patients had total resections without recurrence; 5 had stable residual tumors and 6 had residual tumors that showed progression, all within 1 year after surgery. Among the patients with classic juvenile pilocytic astrocytomas of the cerebellum 7 had residual tumor, which progressed in 2 patients, both of whom had high AgNOR scores. Among 7 patients with optic/hypothalamic tumors the 3 with rapidly progressing tumors all had very high AgNOR scores. The determination of AgNOR expression might be helpful in selection of patients with residual tumor after surgery, who may benefit from additional chemotherapy or (stereotactic) radiation therapy. Received: 12 August 1998 Revised: 22 March 1999     

儿童第三脑室中间块星形细胞瘤

目的 明确第三脑室中间块星形细胞瘤的临床表现、诊断和手术治疗。方法 2例第三脑室肿瘤病儿的影像学检查(头颅CT和MRI)发现第三脑室内边界清楚的圆形或椭圆形占位。经右额胼胝体-透明隔间腔-穹隆间入路，在直视下切除肿瘤，并明确肿瘤起源于中间块。结果 2例病儿的肿瘤为近全切除，术后有头颅CT和MRI证实第三脑室内的瘤体完全消失，肿瘤病理诊断为纤维型星形细胞瘤(I-Ⅱ级)。结论 中间块星形细胞瘤起源于第三脑室的中间块，经胼胝体-透明隔间腔-穹隆间入路可以做到在直视下切除肿瘤和明确肿瘤的真正起源。     

60例中脑肿瘤MR影像分析

目的　研究６０ 例经手术及病理证实的中脑肿瘤的影像学表现。方法　６０ 例术前均行 Ｍ Ｒ 显像,手术全部或部分切除。结果　位于中脑顶盖被盖及导水管的肿瘤大多表现为边界比较清楚的异常信号,而丘脑起源累及中脑的肿瘤多为混杂 Ｔ１ 、 Ｔ２ 信号,边界不清。注射 Ｇｄ Ｄ Ｔ Ｐ Ａ 后,局限于中脑的肿瘤大多不增强。而丘脑起源侵及中脑及中脑向桥脑浸润生长的肿瘤多为不均匀混杂增强。结论　位于及累及中脑的肿瘤,生长部位不同,肿瘤性质不同,肿瘤的生物学性质又决定其生长形态,并表现出某些特殊的影像学特征。术前对 Ｍ Ｒ 表现作出正确分析很有意义。