Gliomatosis cerebri with secondary glioblastoma formation: report of two cases

Differential transformation capacity of neuro-glial progenitors during development

Gliomas represent the most common type of brain tumor, but show considerable variability in histologic appearance and clinical outcome. The phenotypic differences between types and grades of gliomas have not been explained solely on the grounds of differing oncogenic stimuli. Several studies have demonstrated that some phenotypic differences may be attributed to regional differences in the neural stem cells from which tumors arise. We hypothesized that temporal differences may also play a role, with tumor phenotypic variability reflecting intrinsic differences in neural stem cells at distinct developmental stages. To determine how the tumorigenic potential of lineally related stem cells changes over time, we used a conditional transgenic system that integrates Cre-Lox-mediated and Tet-regulated expression to drive K-ras(G12D) expression in neuro-glial progenitor populations at different developmental time points. Using this model, we demonstrate that K-ras(G12D)-induced transformation is dependent on the developmental stage at which it is introduced. Diffuse malignant brain tumors develop during early embryogenesis but not when K-ras(G12D) expression is induced during late embryogenesis or early postnatal life. We show that differential expression of cell-cycle regulators during development may be responsible for this differing susceptibility to malignant transformation and that loss of p53 can overcome the transformation resistance seen at later developmental stages. These results highlight the interplay between genetic alterations and the molecular changes that accompany specific developmental stages; early progenitors may lack the regulatory mechanisms present at later, more lineage-restrictive, developmental time points, making them more susceptible to transformation.

[Gliomatosis cerebri: a biopsy and autopsy case report]

Gliomatosis cerebri is a rare glial neoplasm, characterized by diffuse brain infiltration with relative preservation of the underlying cytoarchitecture. Its clinical and radiologic features are not specific and its antemortem diagnosis is difficult. We report a case of gliomatosis cerebri in a 68-year-old woman presenting with gait disturbances and episodic seizures. MRI showed bilateral white matter hypersignal intensities on Flair sequences and brain biopsy revealed a poorly cellular proliferation of neoplasic glial cells strongly expressing OLIG-2, Ki-67 and occasionally GFAP, without alpha-internexin expression. The patient status worsened rapidly and she died 2 months after the initial symptoms. Postmortem brain examination confirmed gliomatosis cerebri and revealed a focal glioblastoma in the frontal cortex, with nuclear p53 expression in the highest malignant areas. Gliomatosis cerebri should be included in the differential diagnostic of diffuse brain lesions. Antemortem diagnosis, although difficult, can be assessed by IRM and careful biopsy examination. Progression to glioblastoma has been seldom reported, enhancing the controversy about the etiopathogenesis of this rare tumour.

Evaluation of molecular genetic alterations associated with tumor progression in a case of gliomatosis cerebri

Gliomatosis cerebri (GC) is a rare tumor characterized by widespread infiltration of the brain and spinal cord. Although GC usually demonstrates histomorphological features of a low-grade tumor, the formation of secondary highly malignant tumor regions may occur. In order to reveal molecular genetic changes associated with tumor progression in GC, we analyzed factors known to be associated with malignant progression in common astocytomas in an unusual GC case of an 18-year-old patient suffering from this disease for almost 7 years. We detected allelic losses in the Rb gene and in exon 4 of the TP53 gene in a tumor region corresponding to a glioblastoma multiforme. EGFR or MDM2 gene amplifications were absent, and no PTEN mutation or allelic loss on chromosome 10 could be detected. Moreover, compared to tumor-free brain tissue of this patient, tumor regions showed increased EGFR expression. These findings show that malignant progression in GC might be associated with the acquisition of molecular genetic changes also found in low-grade astrocytomas with progression to secondary glioblastoma. These data support the notion that GC can be regarded as a subtype of a common astrocytoma.

Molecular genetic alterations in gliomatosis cerebri: what can we learn about the origin and course of the disease?

Gliomatosis cerebri (GC) is a neuroepithelial neoplasm with extensive infiltration of large parts of the brain. Recent data showing the involvement of TP53 mutation or nuclear protein accumulation in some cases have linked the astrocytic phenotype of the tumor cells to TP53 alterations frequently found in common astrocytomas. However, the frequency of these alterations is low, and other molecular genetic changes have been only rarely identified. Those found in common high-grade astrocytomas and glioblastomas are usually missing in GC. The distribution of TP53 point mutations, as well as non-coding polymorphic markers and some cytogenetic data, support a monoclonal origin in some cases, and are at least compatible with it in most cases, while no conclusive data suggesting a polyclonal origin have been reported. This raises the question of mechanisms responsible for the enhanced infiltrative potential of the tumor cells in this disease, which have not yet been identified.

Assessment of tumor cell invasion factors in gliomatosis cerebri

Gliomatosis cerebri (GC) is a rare brain tumor characterized by widespread infiltration of large parts of the brain and sometimes even the spinal cord. To determine the cause of this extraordinary degree of brain invasion, we studied immunoexpression of factors associated with brain infiltration in low-grade and high-grade tumor samples from nine GC cases. We further determined the allelic status of the fibroblastic growth factor receptor 4 (FGFR4) gene at position 388 (arginine [Arg(388)] or glycine [Gly(388)]) in eighteen GC patients, because the presence of at least one Arg(388) allele has been suggested to favor tumor cell motility compared to tumor cells homozygeous for the Gly(388) allele. Immunohistochemical analyses showed that tumor samples from three GC cases expressed Tenascin-C, whereas six cases had CD44 - immunopositive tumor samples. Expression of MMP-9 was not observed in any of the nine GC patients. FGFR4 genotyping revealed the presence of the Arg(388) in 72% of the eighteen GC cases, a frequency similar to the one found in 21 common astrocytomas (71%). In tumor-free control DNA, the Arg(388) phenotype was present in 60%. These data indicate that CD44 expression might be related to the tumor infiltration in GC, and that patients suffering from GC or other common astrocytomas do not have a significantly increased frequency of the tumor cell motility-favoring Arg(388) FGFR4 allele.

Alterations of cell cycle regulators in gliomatosis cerebri

Gliomatosis cerebri (GC) is regarded as a rare glial neoplasm of unknown origin, and a detailed analysis of molecular alterations underlying this disease has started only recently. However, because GC characteristically affects large parts of the brain and spinal cord, the distribution of genetic alterations may be highly variable between different tumor areas. Additionally, tumor areas with varying degrees of differentiation may be present, raising the possibility to model the genetic events associated with astrocytoma progression. Here we analyzed various tumor regions with features of low-grade and high-grade astrocytomas from 9 autopsy-proven GC cases for the immunoexpression of the cell cycle-controlling proteins mdm2, p21, p27/kip1, p16, and Rb. The samples were also screened for EGFR expression, and for amplification of the EGFR and MDM2 genes. Furthermore, allelic losses of the CDKN2A gene and of a PTEN flanking region of chromosome 10 were determined. We detected tumor regions with immunoexpression of p21 only rarely in our series, without association to the tumor grade. No MDM2 gene amplification was detected. In contrast, three cases demonstrated maintained Rb expression. The expression of p27(kip1) showed a clear reduction with increasing astrocytoma malignancy in 7 cases. Allelic loss of the CDKN2A gene occurred in 5 patients but was not related to the tumor grading, nor to the intensity of p16 immunoexpression. No homozygous CDKN2Adeletions were detected. EGFR amplification was also absent in our series, but one case demonstrated EGFR expression only in the high-grade tumor area. Allelic losses on chromosome 10 were found in one out of six informative cases. However, marked differences in the immunoexpression, as well as in the distribution of genetic aberrations were seen between different tumor samples within a given case. The distribution of the alterations suggests that these molecular genetic changes represent secondary events, which may develop within tumor clones derived from a common founder tumor clone characterized by extraordinary spreading through the brain. Moreover, the detected aberrations in gliomatosis cerebri can reflect the tumor progression associated with secondary malignant astrocytoma formation even within a single case.

Three-dimensional anisotropy contrast imaging of gliomatosis cerebri: two case reports

BACKGROUND

Magnetic resonance imaging (MRI) can provide a preoperative diagnosis of gliomatosis cerebri, but the findings sometimes do not correspond with the clinical symptoms or histologic findings.

CASE DESCRIPTION

Three-dimensional anisotropy contrast (3DAC) imaging was used to assess damage to the neuronal fibers in two patients with gliomatosis cerebri who presented with only mental deterioration. Conventional MRI depicted markedly abnormal findings consisting of widespread areas of abnormally high signal intensity in the corpus callosum and in the bilateral white matter in both cases. In contrast, 3-D AC imaging showed no abnormality except for small dark areas in the corpus callosum or white matter.

CONCLUSION

3-D AC imaging provides more accurate information about damage to the neuronal fibers in cases of gliomatosis cerebri than other MRI techniques.

Gliomatosis cerebri: treatment results with radiotherapy alone

BACKGROUND

Gliomatosis cerebri (GC) is a rare primary brain tumor characterized by proliferation of neoplastic glial cells that typically involve multiple brain areas, with preservation of brain structures and sparing of neurons. The optimal therapeutic strategy is not well established. The impact of radiotherapy on survival in patients with GC remains undefined.

METHODS

Between 1980 and 2001, 12 patients with GC were identified, representing less than 1% of all patients with primary brain neoplasms treated at the Cleveland Clinic.

RESULTS

All 12 patients had brain biopsies between March 1986 and July 2001 (seven males, five females, with a median age of 53 years [range, 13-85 years]). Median Karnofsky performance status at the time of presentation was 70 (range, 40-90). Eight patients had low-grade gliomas and four patients had anaplastic astrocytomas. Eight patients received radiation treatment to the brain as the only treatment, and four received neither radiation nor chemotherapy. The median dose of megavoltage radiation was 55.4 Gy (range, 45-61.2 Gy). Of the eight patients who received brain radiotherapy, the clinical and radiologic follow-up findings improved in three patients, stabilized in three patients, and worsened in two patients. Median follow-up was 10.3 months (range, 1-55 months). The median survival for the eight patients who received brain radiotherapy was 11.4 months. The one- and two-year survival rates were 45% and 30%, respectively. Two of the eight patients who received radiotherapy were alive at the time of writing. The four patients who did not receive radiotherapy died of the disease at 0.6, 1.0, 1.9, and 2.4 months after diagnosis.

CONCLUSIONS

Gliomatosis cerebri is associated with poor survival. Although brain radiotherapy controlled or stabilized disease progression in most patients, the overall survival after brain radiotherapy alone was not satisfactory. More aggressive therapy may be needed.

Gliomatosis cerebri: molecular pathology and clinical course

Gliomatosis cerebri is a rare, diffusely growing neuroepithelial tumor characterized by extensive brain infiltration involving more than two cerebral lobes. Among 13 patients with gliomatosis cerebri (median age, 46 years), biopsies showed features of diffuse astrocytoma (n = 4), oligoastrocytoma (n = 1), anaplastic astrocytoma (n = 5), anaplastic oligoastrocytoma (n = 1), or glioblastoma (n = 2). Molecular genetic investigation showed TP53 mutations in three of seven tumors and both PTEN mutation and epidermal growth factor receptor overexpression in one tumor. Amplification of CDK4 or MDM2 or homozygous deletion of CDKN2A was not detected. Three of 10 patients receiving radiotherapy showed a partial response (one patient) or had stable disease (two patients) lasting for more than 1 year. Four of six patients treated with procarbazine, carmustine, vincristine chemotherapy demonstrated partial remission (one patient), minor response (two patients), or stable disease (one patient). Median survival time from diagnosis was 14 months (range, 4-91+ months). Infratentorial involvement was associated with shorter survival. We conclude that (1) the molecular genetic alterations in gliomatosis cerebri resemble those in diffuse astrocytomas; (2) the prognosis of gliomatosis cerebri is variable but for at least 50% of patients as poor as for glioblastoma; and (3) some patients respond to radiotherapy and/or procarbazine, carmustine, vincristine chemotherapy.

Histological and genetic diagnosis of gliomatosis cerebri: case report

Gliomatosis cerebri is considered grade III astrocytoma because of the short survival period of patients with this tumor, while the tumor histologically consists of widespread low grade astrocytoma cells. The authors tried to clarify this discrepancy by applying genetic analysis of the tumor. A 29-year-old man originally presented with mild headache and showed diffuse high intensity areas in both hemispheres and in the cerebellum by T2-weighted magnetic resonance imaging (MRI) without gadolinium-dimeglumine (Gd)-enhancement in T1-weighted imaging. Histological diagnosis was gliomatosis cerebri with diffuse grade II astrocytoma. Seven months after temporary improvement following irradiation and chemotherapy, he developed progressive mental deterioration, and died in one year after the surgery. At this time T1-weighted imaging showed Gd-enhanced lesions with enlargement only of the cerebellar tumor. Genetic analysis demonstrated positive FGFR 1 and less FGFR 2 mRNA in the tumor tissue, and FGFR 1 mRNA was beta type dominant. These results indicated that the genetic features of this tumor are similar to those of glioblastoma multiforme concerning FGFR expression. The authors conclude that genetic investigation of the tumor tissue is required to predict the prognosis of gliomatosis cerebri patients, in addition to imaging and histological examinations.