Surgical management of cerebral metastases

Important issues related to surgery for patient with cerebral metastases, including surgical anatomy and techniques, patient selection criteria, surgery for multiple and recurrent metastases, and the roles of adjunctive whole brain radiation, and stereotactic radiosurgery. A practical algorithm for decision making and survival statistics for the common metastatic tumors have been developed.

Pathways leading to glioblastoma multiforme: a molecular analysis of genetic alterations in 65 astrocytic tumors

To characterize some of the genetic events underlying the development of glioblastoma multiforme, the authors analyzed 65 astrocytic tumors (seven pilocytic astrocytomas, eight astrocytomas, 16 anaplastic astrocytomas, and 34 glioblastomas multiforme) for loss of heterozygosity for chromosome 17p, loss of heterozygosity for chromosomes 10p and 10q, amplification of the epidermal growth factor receptor (EGFR) gene, and amplification of the oncogenes N-myc, c-myc, and N-ras using Southern blot analysis. Alterations of the p53 gene (positive immunostaining for p53 protein in tumors with or without p53 gene mutations) in these 65 tumors were analyzed previously. None of the 65 tumors showed amplification or rearrangement of N-myc, c-myc, or N-ras oncogenes. The molecular analysis presented here demonstrates distinct variants of astrocytic tumors, with at least three genetic pathways leading to glioblastoma multiforme. One pathway was characterized by 43 astrocytomas with alterations in p53. Glioblastomas with p53 alterations may represent tumors that progress from lower-grade astrocytomas. This variant was more likely to show loss of chromosome 17p than tumors without p53 alterations (p < 0.04). Seventy-five percent of tumors with loss of one 17p allele demonstrated mutations in the p53 gene. Loss of chromosome 10 was associated with progression from anaplastic astrocytoma (13%) to glioblastoma (38%) (p < 0.04). Amplification of the EGFR gene was a rare (7%) but late event in tumor progression (p < 0.03). A second pathway was characterized by six astrocytomas without p53 alterations and may represent clinically de novo high-grade tumors. These tumors were more likely to show amplification of the EGFR gene (83%) than tumors with p53 alterations. Sixty percent of tumors with EGFR amplification also showed loss of chromosome 10; loss of chromosome 17p was infrequent in this variant. One or more alternative pathways were characterized by 16 astrocytomas without p53 alterations and with none of the genetic changes analyzed in this study. Glioblastomas are a heterogeneous group of tumors that may arise via multiple genetic pathways.

Inclusion of the S2 dorsal rootlets in functional posterior rhizotomy for spasticity in children with cerebral palsy

Many neurosurgeons have made a practice of sectioning the S2 dorsal roots during selective posterior rhizotomy for the treatment of spasticity in children with cerebral palsy, but the efficacy of this treatment has not previously been proven. S2 afferents are involved in reflex arcs of the plantar flexors (PFs), so that S2 lesioning should in theory reduce PF spasticity. To test this assumption, we determined the frequency of postoperative residual spasticity in the PFs when S2 lesioning was or was not performed. We assessed 85 children for whom 6-month follow-up was available. Functional rhizotomy from L2-S1 was performed on 13 of them (26 legs with PF spasticity) and from L2-S2 on 72 (141 legs with PF spasticity). Rootlets were lesioned if there was an abnormal response to intraoperative electrical stimulation. In 20 patients, lesioning of the S2 rootlets was assisted by the "pudendal neurogram," a technique previously shown to prevent bladder dysfunction during sectioning of the sacral roots. When S2 roots were excluded from the lesioning process, residual PF spasticity was detected in 35% of the legs that had it preoperatively, leaving 5 (38%) of 13 children with functionally impairing spasticity. When S2 roots were included, 6% of legs that had PF spasticity retained it postoperatively (P < 0.001), leaving 8 (11%) of 72 patients with functionally limiting spasticity (P < 0.05). Thus, the addition of the S2 roots to the procedure resulted in an 81% reduction in the number of legs with residual PF spasticity and a 71% reduction in the number of patients with residual PF spasticity.(ABSTRACT TRUNCATED AT 250 WORDS)

High frequency of p53 protein accumulation without p53 gene mutation in human juvenile pilocytic, low grade and anaplastic astrocytomas

We analysed 31 non-glioblastoma astrocytomas for alterations in p53 protein expression and for mutations in the p53 gene. Immunohistochemistry detected p53 protein accumulation in 71% (five of seven) of juvenile pilocytic astrocytomas (WHO grade I), 63% (five of eight) of astrocytomas (WHO grade II), and 63% (10 of 16) of anaplastic astrocytomas (WHO grade III). The single strand conformation polymorphism (SSCP) assay of exons 2-11 of the p53 gene and direct DNA sequencing identified p53 mutations in 14% (one of seven) of grade I, 25% (two of eight) of grade II, and 19% (three of 16) of grade III astrocytomas. This is the first report of a p53 mutation in grade I juvenile pilocytic astrocytomas. Immunohistochemistry and SSCP analyses gave concordant results in 55% (17 of the 31) of the tumors. A total of 14 tumors, 60-80% within each grade, showed p53 protein accumulation in the absence of detectable mutations of the p53 gene. No mdm-2 gene amplification was found in these tumors. The similar frequency of p53 alterations in tumors of grades I-III suggests that the p53 gene plays a significant role early in the formation of astrocytomas rather than late in tumor progression to higher grade. The data suggest that mechanisms other than p53 gene inactivation by mutation or mdm-2 complex formation result in the accumulation of P53 protein in > 70% of non-glioblastoma astrocytomas.

Central nervous system gangliogliomas. Part 1: Pathology

Histopathological features that suggest the diagnosis of ganglioglioma require, in most cases, confirmation by special stains to distinguish these tumors from other gliomas. For this purpose, immunostaining for synaptophysin, which has previously been shown to selectively label the cell surface of neoplastic ganglion cells, was used to retrospectively examine glioma tumor specimens. Sixty-three cases of ganglioglioma were identified. The files of the Division of Neuropathology of New York University Medical Center contained 45 tumors that had been diagnosed as ganglioglioma, of which 42 were verified by synaptophysin; three cases were reclassified, two as astrocytomas and one as a gangliocytic paraganglioma. Thus, a tumor identified as ganglioglioma based on other criteria was likely to be a ganglioglioma. The other 21 cases of gangliogliomas were originally diagnosed as astrocytoma or mixed glioma, but were shown by synaptophysin staining to be gangliogliomas. In some cases the ultimate diagnosis was obtained after radical surgery provided relatively abundant amounts of tissue, thereby limiting sampling errors, in contrast to the biopsies from which the original diagnoses were made. Histopathological review of these cases demonstrated that four features represent important clues to the correct diagnosis: 1) clusters of large cells potentially representing neurons (without such cells the tumor cannot be classified as a ganglioglioma); 2) no perineuronal clustering of the glial cells around the alleged neoplastic neurons; 3) fibrosis (desmoplasia); and 4) calcification. Binucleate neurons, previously suggested to be common in gangliogliomas, were not frequently found in this series, and lymphocytic infiltrates, while common, are so often found in other tumors that they gave no specific hint that any single neoplasm was a ganglioglioma. The glial elements were astrocytic in all cases, except that one tumor also had oligodendroglial and ependymal patterns. Four tumors also had small mature neurons, as seen in neurocytomas. Cells from one tumor were successfully grown in short-term tissue culture; the culture contained large dividing neurons with synaptophysin immunoreactivity as well as smaller dividing cells, demonstrating that the neuronal cells are a proliferating element in gangliogliomas.

Central nervous system gangliogliomas. Part 2: Clinical outcome

The records of 58 patients with gangliogliomas surgically treated between January 1, 1980, and June 30, 1990, were retrospectively reviewed in order to determine long-term survival, event-free survival, and functional outcome resulting after radical resection and to assess the impact of histological grading on outcome. Tumors were located in the cerebral hemisphere in 19 cases, the spinal cord in 30, and the brain stem in nine. Forty-four patients had gross total resection and 14 had radical subtotal resection. Only six patients underwent postoperative irradiation or chemotherapy and, therefore, the outcome was generally related to surgery alone. Of the 58 gangliogliomas, 40 were classified as histological grade I, 16 were grade II, and two were grade III. The median follow-up period was 56 months. There were no operative deaths, and the operative morbidity rate was 5%, 37%, and 33% for cerebral hemisphere, spinal cord, and brain-stem gangliogliomas, respectively. The 5-year actuarial survival rates for cerebral hemisphere, spinal cord, and brain-stem gangliogliomas were 93%, 84%, and 73%, respectively (p = 0.7). The event-free survival rate at 5 years was 95% for cerebral hemisphere gangliogliomas and 36% for spinal cord gangliogliomas (p < 0.05); for brain-stem gangliogliomas the event-free survival rate at 3 years was 53% (p < 0.05). Neurological function at recent follow-up evaluation was stable or improved in 81% of patients. Multivariate analysis (Cox linear regression) revealed tumor location to be the only variable predictive of outcome, with spinal cord and brain-stem gangliogliomas having a 3.5- and 5-fold increased relative risk of recurrence, respectively, compared to cerebral hemisphere gangliogliomas. Histological grade was not predictive of outcome, although in each location there was a trend for higher-grade tumors to have a shorter time to recurrence. It is concluded that radical surgery leads to long-term survival of patients with gangliogliomas, regardless of location, and adjuvant therapy can probably be reserved for special cases.

A correlative study of p53 protein alteration and p53 gene mutation in glioblastoma multiforme

The p53 tumor suppressor gene is frequently mutated in glioblastomas. Mutations within the p53 gene often result in aberrant expression of the p53 protein leading to protein accumulation within the nucleus of the cells which can be detected by immunochemistry. Many studies have correlated alterations of p53 protein expression with p53 gene mutations. Positive staining of tumor cells for p53 protein has been widely assumed, perhaps incorrectly, to signify the presence of p53 gene mutations. This study compared the immunostaining patterns for p53 protein in 37 glioblastomas with the molecular genetic data obtained by the single strand conformation polymorphism assay. p53 gene mutations were detected in 46% (17 of 37) of glioblastomas, while 65% (24 of 37) of glioblastomas were positive for protein accumulation by immunohistochemistry. Although 30 of 37 glioblastomas analyzed showed concordance for p53 protein expression and p53 gene mutations, a subset of seven glioblastomas showed discordant accumulation of the p53 protein in the absence of any detectable p53 gene mutations. The mdm-2 gene was assessed in 17 glioblastomas for gene rearrangements or amplification, but none were found. This result suggests that a mechanism other than p53 gene mutation can result in altered p53 protein expression.

Insulin and insulin-like growth factor II permit nerve growth factor binding and the neurite formation response in cultured human neuroblastoma cells

In serum-free medium, SH-SY5Y human neuroblastoma cells specifically and reversibly lost the capacity to bind 125I-labeled nerve growth factor (NGF) to the high-affinity sites (slow sites) and to respond by neurite outgrowth, unless physiological concentrations of insulin or insulin-like growth factor II were present. In serum-containing medium, anti-insulin antiserum decreased the neurite formation response to NGF, and insulin supplementation increased the number of available NGF slow sites. The low-affinity NGF fast sites are absent from SH-SY5Y cells and did not emerge on treatment with insulin. Insulin potentiated the induction of neurites by NGF in rat pheochromocytoma PC12 cells also. These results implicate a wider role for insulin and its homologs in the nervous system.