Lack of histopathological correlation of malignant ependymomas with postoperative survival

Proliferation- and apoptosis-related proteins in intracranial ependymomas: an immunohistochemical analysis

As the value of grading of ependymomas is currently debated we studied the expression of proliferation- and apoptosis-related proteins in these tumors as these mechanisms both are suggested to be important in tumor growth. We characterized the immunohistochemical expression of p53, Mdm2, Bcl-2, and Bax in 51 intracranial ependymomas. We also assessed the apoptosis- and proliferation-index, measured by MIB-1, PCNA-immunohistochemistry, and analyzed the clinical parameters. Of all used antibodies, the correlation with survival and the correlation among ordered categories was assessed. None of the analyzed immunohistochemical variables were significantly correlated with tumor grade. On the other hand, PCNA, MIB-1, and p53 were significantly related to the survival of the patient. In multivariate analysis, p53 was the only independent predictive variable (p = 0.0132).

CONCLUSION

The strongest predictors of survival in univariate analysis were the expression of PCNA, MIB-1 and p53. In multivariate analysis a p53 expression > 1% showed to be significantly related with a worse survival. The predicting value of p53 expression has to be confirmed by others before solid conclusions can be made. Apoptosis seems not to be an important mechanism in tumor growth in ependymomas. The expression of Mdm2, Bcl-2, and Bax were not related to survival.

CDKN2A/p16 in ependymomas

Sixteen cases of ependymoma were studied for CDKN2A/p16 inactivation by immunohistochemistry using a p16 monoclonal antibody, by homozygous deletion (HD) assay and 5'CpG promoter methylation assay (methylation-specific PCR). Three out of 16 cases were p16 immuno-negative: two corresponded to grade II ependymomas and one to grade III. The latter ependymoma, characterized by a high Ki-67/MIB-1 LI, was the only one of the whole series to show CDKN2A HD. No promoter methylation was found in the two immuno-negative cases without CDKN2A HD. Alternative mechanisms, such as point mutations or alterations in p16 post-translational regulation, may be responsible for p16 inactivation. Since in our series just one out of eight anaplastic cases showed negative immunostaining and CDKN2A HD, p16/CDKN2A inactivation may not play an important role in the malignant transformation of ependymomas. Amplification of CCNDI and CDK4, p27/Kipl degradation and TP53 mutations were previously studied by other authors and were demonstrated not to correlate with anaplasia. Up to date, molecular genetic studies have not been useful in recognizing the anaplastic variant in ependymomas.

A clinicopathologic study of 81 patients with ependymomas and proposal of diagnostic criteria for anaplastic ependymoma

Optimal histologic criteria for the classification of and grading of ependymomas, including their anaplastic forms, remain elusive. This is especially true because of the poor correlation of these criteria with clinical outcome. The aim of this study was to identify the histopathologic parameters that could distinguish different prognostic groups of patients with ependymomas. Eighty-one patients with ependymal tumors, including those originally diagnosed ependymomas, anaplastic ependymomas and myxopapillary ependymomas, were enrolled in this study. Thirteen histologic parameters, including hypercellularity, nuclear pleomorphism, mitoses, endothelial proliferation, necrosis, clear cell, thrombi, dystrophic calcification, psammoma bodies, bone, cartilage, Rosenthal fibers and MIB-1 labeling index (LI), were evaluated in each patient and correlated with clinical outcome. We assigned one score for each histopathologic parameter evaluated and used a stepwise selection method with entry model based on the significance of the log-rank statistic to formulate a scoring model. Four parameters were chosen in this process, including mitoses > or = 4/10 hpf (1.7/mm2), hypercellularity, endothelial proliferation and necrosis. The sum of these four parameters (scores) was the histopathologic score of the tumor. The progression-free survival (PFS) and overall survival (OS) of patients with histopathologic scores 0 and 1 were significantly better than those with histopathologic scores 2, 3 and 4 (p < 0.001 and p = 0.005, respectively). Because of the latter finding, we proposed that anaplastic ependymoma could be diagnosed by the presence of any two of the aforementioned four parameters. Multivariate analyses including clinical and histopathologic variables showed that histopathologic score > or = 2 and subtotal resection were the factors related to increased risk of recurrence, while histopathologic score > or = 2 was the only factor related to overall survival. Based on the above findings, we concluded that histopathology is an important prognostic indicator for patients with ependymomas.

Differential expression of somatostatin receptors in ependymoma: implications for diagnosis

Somatostatin receptors (SSts) have been found in a variety of brain tumors, e.g., meningiomas, medulloblastomas and astrocytomas. Our aim was to investigate their expression in ependymomas. Using RT-PCR, expression of mRNA for the different SSt subtypes was analyzed and quantified in 28 ependymomas and correlated with different variables (age, tumor location, histological grade, recurrence and survival). In addition, in 8 cases, protein expression was studied in vitro, using immunohistochemistry, and in vivo, by somatostatin scintigraphy. mRNAs for all 5 subtypes were variably expressed in each ependymoma. The Southern blotting signal obtained after SSt(1) and SSt(2) amplification was higher than that for the other receptor subtypes. No significant correlation was seen between the level of SSt(1) and SSt(2) mRNA expression and age, location, histological grading, recurrence or survival. In the 8 cases, SSt(1) staining was negative in 3 and low in 5. Staining for SSt(2A) was positive but low in every specimen analyzed. SSt(1) and SSt(2) immunoreactivity was seen only in the cytoplasm of tumoral cells. Somatostatin scintigraphy showed clear uptake, which agreed with MRI data in the majority of cases. However, no correlation was seen between tracer uptake intensity and histological grade, SSt(1) and SSt(2) mRNA expression or immunostaining intensity. This evidence for the expression of SSt(2) receptors in ependymomas opens interesting prospects for their follow-up.

Chromosomal abnormalities subdivide ependymal tumors into clinically relevant groups

Ependymoma occurs most frequently within the central nervous system of children and young adults. We determined relative chromosomal copy-number aberrations in 44 ependymomas using comparative genomic hybridization. The study included 24 intracranial and 20 spinal cord tumors from pediatric and adult patients. Frequent chromosomal aberrations in intracranial tumors were gain of 1q and losses on 6q, 9, and 13. Gain of 1q and loss on 9 were preferentially associated with histological grade 3 tumors. On the other hand, gain on chromosome 7 was recognized almost exclusively in spinal cord tumors, and was associated with various other chromosomal aberrations including frequent loss of 22q. We conclude that cytogenetic analysis of ependymomas may help to classify these tumors and provide leads concerning their initiation and progression. The relationship of these aberrations to patient outcome needs to be addressed.

Recurrent intracranial ependymoma in children: salvage therapy with oral etoposide

Chronic oral VP-16 (etoposide) is a chemotherapy regimen with a wide application in oncology and documented efficacy against germ cell tumors, lymphomas, Kaposi's sarcoma, and primary brain tumors. This study was performed to assess the toxicity and activity of chronic oral etoposide in the management of children with recurrent intracranial nondisseminated ependymoma. Twelve children (median age of 8 years) with recurrent ependymoma who were refractory to surgery, radiotherapy, and chemotherapy (carboplatinum or the combination of procarbazine, lomustine, and vincristine) were treated with chronic oral etoposide (50 mg/m(2)/day). Treatment-related complications included the following: alopecia (10 children), diarrhea (6), weight loss (5), anemia (4), neutropenia (3), and thrombocytopenia (3). Three children required transfusion (two with packed red blood cells; two with platelets), and two children developed neutropenic fever. No treatment-related deaths occurred. Six children (50%) demonstrated either a radiographic response (two children, both with partial response) or stable disease (four children) with a median duration of response or stable disease of 7 months. In this small cohort of children with recurrent intracranial ependymoma, oral etoposide was well tolerated, produced modest toxicity, and had apparent activity.

Surveillance neuroimaging in childhood intracranial ependymoma: how effective, how often, and for how long?

OBJECT

The authors examined images obtained in 52 children with intracranial ependymomas to determine risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcome.

METHODS

Data obtained in all children with intracranial ependymomas were prospectively entered into a database from January 1987 to June 2000. The imaging and clinical details in all patients were reviewed. Fifty-two children with histologically proven intracranial ependymomas were treated at the authors' institution; recurrences developed in 28 (54%) of them, with a median time from surgery to first recurrence of 14.5 months (range 3-65 months). Of these tumor recurrences, 43% were asymptomatic and were noted on surveillance imaging. Seventeen children died, all of whom had recurrences. Incomplete excision of the primary tumor was significantly associated with reduced time to recurrence (p = 0.0144) and time to death (p = 0.0472). The age of the patient, location of the primary tumor, histological findings, and the presence or absence of spinal metastases on preoperative imaging were not significantly associated with outcome. The risk of death at any given time was 12-fold greater in patients in whom a recurrence was identified due to symptoms rather than on surveillance images (p = 0.016).

CONCLUSIONS

Recurrent childhood ependymoma has a poor prognosis. The extent of the initial local tumor resection is the factor most closely associated with outcome. Surveillance imaging reveals a substantial number of asymptomatic recurrences, and survival appears to be improved in these patients compared with those identified by symptoms. The improvement in survival is thought to be greater than that expected just from earlier diagnosis.

Neoplastic meningitis: diagnosis and treatment considerations

Neoplastic meningitis is an increasingly recognized complication of advanced metastatic cancer and, if left undiagnosed or untreated, is characterized by rapid neurologic deterioration and death. Thus, the diagnosis and treatment of neoplastic meningitis present challenges for the clinical oncologist. The diagnosis of neoplastic meningitis is based on clinical signs and symptoms, laboratory analysis of cerebrospinal fluid to determine cell count and cytology, and analysis of neuroimaging studies for evidence of leptomeningeal or cranial nerve enhancement. Once diagnosed, conventional treatment regimens may include radiotherapy combined with systemic or intrathecal chemotherapy, often with the antimetabolites cytarabine and/or methotrexate. However, the prognosis for neoplastic meningitis secondary to an underlying solid tumor or recurrent leukemia is poor with conventional treatment regimens. Therefore, novel agents for intrathecal administration, including DepoCyttrade mark, mafosfamide, and topotecan, or novel therapeutic approaches, including conjugated monoclonal antibodies and immunotoxins or gene therapy, are currently under investigation. Such new agents and therapeutic approaches will facilitate the development of effective treatment strategies and will ultimately improve the outcome for patients with this devastating disease. This article provides an overview of the approaches to the diagnosis, evaluation, and treatment of neoplastic meningitis.

Immunohistochemical markers for intracranial ependymoma recurrence. An analysis of 88 cases

Intracranial ependymomas are the third most common primary brain tumor in children. Although clinical and histological criteria for ependymoma prognosis are recognized, studies have reported contradictory results. Prognostic significance based on immunohistochemistry of ependymomas has been reported in a few studies. Eighty-eight patients with intracranial ependymomas were examined retrospectively for immunoexpression of various tumor-associated antigens and apoptosis. The results demonstrated significant preponderance of expression of the tenascin, vascular endothelial growth factor protein (VEGF), epidermal growth factor (EGFR), and p53 protein in high-grade tumors. Also high-grade ependymomas revealed more prominent labeling indices (LI) for proliferative marker Ki-S1 and lower LI for cyclin-dependent kinase inhibitor p27/Kip1. For low-grade ependymomas the progression free survival time (PFS) was found to be significantly shorter for Ki-S1 LI>/=5%, and for tenascin, VEGF, and EGFR positivity. For high-grade ependymomas PFS was found to be significantly reduced for age <16 years, subtotal tumor removal, p27 LI <20%, p53 positivity, and for apoptotic index (AI) <1%. The classification regression tree analysis exhibited four groups of ependymomas; (1) low-grade tenascin negative (32 cases, recurrence rate=0), (2) high-grade with AI >/=1% (21 cases, recurrence rate=57%), (3) low-grade tenascin-positive (10 cases, recurrence rate=89%), and (4) high-grade with AI <1% (25 cases, recurrence rate=100%). So, the immunohistochemical variables were found to be strongest predictors of ependymoma recurrence and they seem to be useful for assessing individual tumor prognosis in routinely processed biopsy specimen.

Prognostic value of immunoexpression of the chemoresistance-related proteins in ependymomas: an analysis of 76 cases

Intracranial ependymomas are the third most common primary brain tumor in children. A variety of chemotherapy protocols have been introduced for the treatment of ependymoma although overall these have not contributed to patients outcome. To our knowledge, data on the prognostic value of immunoexpression of the chemoresistance-related proteins (ChRPs) in ependymomas are absent. Seventy-six patients with intracranial ependymomas who received combined treatment were studied retrospectively. Tumor specimens were immunohistochemically examined with antibodies to metallothioneins (MT), glutathione S-transferase pi (GST pi) and P-glycoprotein (P-GP). The results demonstrated significant preponderance of expression of all the above-mentioned ChRPs for the low-grade tumors. The progression-free survival time was found to be significantly shorter for immunonegative tumors in both tumor grades. Multivariate analysis using a Cox hazard model revealed that recurrence-free survival time is significantly associated with tumor grade, and MT and P-GP expression. Risk of recurrence increased for the high-grade ependymomas (hazard ratio 2.85; P = 0.004), and decreased for the MT-positive tumors (hazard ratio -2.72; P = 0.005) and for the P-GP-positive tumors (hazard ratio -2.02; P = 0.02). The obtained results allow one to conclude that ChRPs expression is closely associated with low-grade ependymomas and immunohistochemical findings may be estimated as a predictor for local tumor progression.

Combined treatment of fourth ventricle ependymomas: report of 26 cases

BACKGROUND

This study investigated the relevance of prognostic factors and the impact of histological features in posterior fossa ependymoma.

METHODS

The charts of 26 patients (aged 1-59 years, mean 20.6 years; 11 adults) with posterior fossa ependymoma operated on between January 1983 and December 1994 were reviewed and patients followed up (mean: 93 months).

RESULTS

Gross total resection was performed in 18 patients (69%), subtotal in seven patients (27%), biopsy in one patient (4%). One patient (3.8%) developed respiratory complications and died. All patients underwent posterior fossa radiotherapy (5000 cGy) after surgery. Four children first received chemotherapy and then radiotherapy only when at least 3 years old. Eleven patients (42%) received radiotherapy and subsequently chemotherapy. The 5-year survival rate was 90% for adults and 40% for children (</= 6 years).

CONCLUSIONS

This review suggests that a) younger patients (</= 6 years), despite multimodality treatment, have a poor prognosis; b) the microanatomical location of the tumor (lateral recess, roof, and floor) influences the extent of tumor removal (p < 0.05); c) longer survivals are associated with complete removal (p < 0.05); d) the histological feature most often related to a poor prognosis is a high mitotic index (p < 0.05), whereas vascular proliferation (p = 0.149), necrosis (p = 0.215), nuclear atypia (p = 0.384) and high cellularity (p = 0.786) do not affect survival; e) histological classification (WHO) does not reflect different survival rates between ependymomas and anaplastic ependymomas (p = 0.082).

The immunophenotype of ependymomas

The morphologic distinction of ependymomas with epithelial cytology from metastatic carcinoma may pose a significant problem in differential diagnosis. The known presence of keratin in glioma cells further complicates the issue. Using the labeled streptavidin-biotin method with automated staining, we studied epithelial and glial marker expression in 52 ependymomas of varying type and grade, including 20 epithelial-appearing, 14 glial-appearing, eight mixed pattern, and 10 myxopapillary tumors; 38 were low grade and 14 anaplastic. All tumors were immunoreactive for glial fibrillary acidic protein (GFAP), and S-100 protein. Diffuse staining for GFAP was noted in glial-appearing ependymomas featuring perivascular pseudorosettes. Diffuse immunostaining for S-100 protein was seen in cellular lesions exhibiting epithelial-like features. Staining was more diffuse for GFAP than S-100 protein in anaplastic ependymomas. Keratin (AE1/AE3) reactivity was seen in 98% of cases, the pattern being similar to that of GFAP. The frequency of staining for other keratins varied: wide-spectrum keratin (35%), cytokeratin (CK)7 (20%), CAM 5.2 (19%), CK903 (14%), and CK20 (8%); as a rule, it was scant and limited to occasional cells and processes. epithelial membrane antigen (EMA) staining was seen in 36% of all cases and in 67% of epithelial-appearing tumors wherein it often high-lighted microlumina. Aside from AE1/AE3 staining and very infrequent wide-spectrum keratin and EMA reactivity, expression of epithelial markers was not seen in anaplastic ependymomas. No carcinoembryonic antigen (CEA) positivity was noted in any case. Collagen IV reactivity was limited to tumor cell-stroma interfaces. Although variable, S-100 protein and GFAP staining is seen in all ependymomas, particularly in true and perivascular pseudorosettes. Widespread reactivity for keratin AE1/AE3 corresponds closely to the pattern of GFAP staining. Significant staining for other keratins or for CEA is inconsistent with a diagnosis of ependymoma. EMA reactivity is largely limited to luminal staining of rosettes and tubules.

Combined postoperative irradiation and chemotherapy for anaplastic ependymomas in childhood: results of the German prospective trials HIT 88/89 and HIT 91

PURPOSE

To evaluate the outcome in children with anaplastic ependymomas after surgery, irradiation, and chemotherapy; and to identify prognostic factors for survival.

METHODS AND MATERIALS

Fifty-five children (n = 27 girls, 28 boys; median age at diagnosis, 6.2 years) with newly diagnosed anaplastic ependymomas were treated in the multicenter, prospective trials HIT 88/89 and HIT 91. Macroscopic complete resection was achieved in 28 patients; 27 patients underwent incomplete resection. All patients received chemotherapy before (n = 40) or after irradiation (n = 15). The irradiation volume encompassed either the neuraxis followed by a boost to the primary tumor site (n = 40) or the tumor region only (n = 13). No radiotherapy was administered in two patients.

RESULTS

Median follow-up was 38 months. The overall survival rate at 3 years after surgery was 75.6%. Disease progression occurred in 25 children with local progression occurring in 20. The median time to disease progression was 45 months. The only significant prognostic factor was the extent of resection (estimated progression-free survival [EPFS] after 3 years was 83.3% after complete resection and 38.5% after incomplete resection) and the presence of metastases at the time of diagnosis (0% vs. 65.8% 3-year EPFS in localized tumors). Age, sex, tumor site, mode of chemotherapy, and irradiation volume did not influence survival.

CONCLUSIONS

Treatment centers should be meticulous about surgery and diagnostic workup. Because the primary tumor region is the predominant site of failure it is important to intensify local treatment. Dose escalation by hyperfractionation or stereotactic radiotherapy might be a promising approach in macroscopically residual disease. The role of adjuvant chemotherapy requires further study.

Molecular genetic analysis of ependymal tumors. NF2 mutations and chromosome 22q loss occur preferentially in intramedullary spinal ependymomas

Ependymal tumors are heterogeneous with regard to morphology, localization, age at first clinical manifestation, and prognosis. Several molecular alterations have been reported in these tumors, including allelic losses on chromosomes 10, 17, and 22 and mutations in the NF2 gene. However, in contrast to astrocytic gliomas, no consistent molecular alterations have been associated with distinct types of ependymal tumors. To evaluate whether morphological subsets of ependymomas are characterized by specific genetic lesions, we analyzed a series of 62 ependymal tumors, including myxopapillary ependymomas, subependymomas, ependymomas, and anaplastic ependymomas, for allelic losses on chromosome arms 10q and 22q and mutations in the PTEN and NF2 genes. Allelic losses on 10q and 22q were detected in 5 of 56 and 12 of 54 tumors, respectively. Six ependymomas carried somatic NF2 mutations, whereas no mutations were detected in the PTEN gene. All six of the NF2 mutations occurred in ependymomas of WHO grade II and were exclusively observed in tumors with a spinal localization (P = 0.0063). These findings suggest that a considerable fraction of spinal ependymomas are associated with molecular events involving chromosome 22 and that mutations in the NF2 gene may be of primary importance for their genesis. Furthermore, our data suggest that the more favorable clinical course of spinal ependymomas may relate to a distinct pattern of genetic alterations different from that of intracerebral ependymomas.

Extraventricular cerebral anaplastic ependymomas

BACKGROUND

Anaplastic ependymomas are considered to be uncommon cerebral tumors by most authors. We have had the opportunity to study 34 cases of such lesions in 13 years.

METHODS

34 cases of anaplastic ependymoma operated in different hospitals of Maracaibo, Venezuela, during the period of 1983-1995 were analyzed. Cases of ependymoblastoma were excluded.

RESULTS

Adult patients made up most of the present series. All patients harbored supratentorial growths in locations distant from the ventricular system. The microscopic pattern was of limited value to establish prognosis, for there was no constant correlation between the histologic features and tumor relapse; only in sporadic cases in which high cell density and conspicuous mitotic activity were maximally expressed, did tumor relapse occur shortly after removal of the lesion.

CONCLUSION

This type of paradoxical behavior being the rule makes all attempts at predicting prognosis in these entities a disappointing task.

The role of surgery in pediatric gliomas

Pediatric glial tumors differ from adult gliomas in several ways that are of major therapeutic importance. First, the value of extensive tumor resection, which is controversial for malignant intrinsic brain tumors in adults, has been confirmed for a variety of childhood brain tumors, such as supratentorial high-grade and low-grade gliomas and infratentorial low-grade gliomas, ependymomas, and some medulloblastomas. Second, chemotherapy has been found to be effective in improving overall outcome in several childhood brain tumors, such as medulloblastoma and supratentorial high-grade glioma, but has yet to be proven to have a major benefit for adult tumors. In addition, chemotherapy is increasingly used to delay or avoid radiotherapy in young children with high-grade and incompletely resected low-grade tumors to avoid the morbidity of irradiation on the developing nervous system. Third, the prognosis for histologically similar tumors is often more favorable in children than adults. The present chapter will highlight the unique features of childhood glial tumors, discuss general principles in the clinical presentation, diagnostic evaluation, and treatment of these tumors, and then focus on the surgical management and outcome of the more common types of tumors.

Supratentorial ependymomas in adult patients

OBJECTIVE

Ependymomas arise from different areas in the neuraxis and have variable outcomes that depend on tumor location and patient age at the time of presentation. The predictive value of histology for these tumors is unresolved. We report a series of adult patients with supratentorial ependymomas to characterize the roles of surgery, histology, ploidy, and proliferation index in tumor control.

METHODS

Fourteen of the 23 supratentorial ependymomas were in the region of the third ventricle and the remainder were located in the hemispheres. Resections were gross total in 12 patients, subtotal in 8, and biopsy in 3. A single pathologist reviewed all slides and quantitated the deoxyribonucleic acid. The mean follow-up duration was 95 months (+/-75 mo).

RESULTS

All of the malignant ependymomas were hemispheric (n = 4). Mortality occurred only in patients with third ventricular tumors; two patients died as a result of surgical complications and three as a result of tumor progression. Kaplan-Meier estimates of 5- and 10-year survival rates were 100% for hemispheric and 72.5% for third ventricular tumors (62.5% including the two perioperative deaths). The median time to recurrence was 53 months, with a 10-year progression-free survival rate of 27%. Univariate analysis revealed that recurrence was associated with malignant histology, including mitoses, cellularity, and aneuploidy. For nonmalignant ependymomas, recurrence was associated with subtotal resection and metastases. S-phase fraction did not correlate with recurrence. Only malignant histology correlated with recurrence on multivariate analysis.

CONCLUSION

Although the numbers are too small to draw any definite conclusions, treatment of ependymomas that arise in the supratentorial compartment in adult patients results in excellent outcomes despite frequent recurrences. Association with the third ventricle and metastases seem to have a negative impact on survival, whereas malignant histology, subtotal resection, and metastases may be predictors of recurrence.

Chromosome arm 6q loss is the most common recurrent autosomal alteration detected in primary pediatric ependymoma

We analyzed 23 samples of primary pediatric ependymoma for significant gains or losses of genomic DNA, using comparative genomic hybridization (CGH) and a rigorous statistical approach. Nine of the tumors in this series (39%) appeared normal by CGH. The remainder had a limited number of regions of genomic imbalance, most often involving losses of chromosome arms 6q and 22q and the X chromosome, or gains of either 1q or 9. Recurrent and exclusive losses of 6q or 22q suggest that these regions harbor tumor suppressor genes that may contribute independently to the pathogenesis of childhood ependymoma.

Pediatric brain tumors

Pediatric brain tumors differ from adult brain tumors in several major ways. First, the types of tumors encountered in children are uncommon in adults, and vice versa. Second, tumors of the posterior fossa comprise a far greater percentage of tumors in children as compared to adults. Third, the value of extensive tumor resection, which is controversial for malignant brain tumors in adults, has been confirmed for a variety of childhood brain tumors. Fourth, chemotherapy has been shown to be effective in improving overall outcome in several childhood brain tumors, but has yet to be demonstrated to have a major benefit for adult tumors. In addition, to avoid the morbidity of irradiation on the developing nervous system, chemotherapy is increasingly used to delay or avoid using radiotherapy in children younger than 3 years of age with high-grade and incompletely resected low-grade tumors. Fifth, the prognosis for histologically similar tumors is often more favorable in children than adults. A review of general principles in the clinical presentation, diagnostic evaluation, and treatment of childhood brain tumors is followed by discussion of surgical management, adjuvant therapy, and outcome of the more common types of tumors.

Ki-67 immunolabelling index is a prognostic indicator in childhood posterior fossa ependymomas

Conventional histological evaluation and subclassification of childhood ependymomas poorly predict their biological behaviour. The Ki-67 labelling index (Ki-67 LI), a measure of growth fraction, correlates with the biological behaviour of several neoplasms, and this retrospective study tested the hypothesis that Ki-67 LI is a prognostic indicator in childhood posterior fossa ependymomas. Immunocytochemistry using an antibody to Ki-67 was undertaken on 5 microns sections of formalin-fixed, paraffin-embedded tissue from 74 cases of childhood (age < 16 years.) posterior fossa ependymoma. A Ki-67 LI was established by counting the proportion of labelled nuclei in more than 1000 cells from several histological fields. Several clinical and histological variables (including Ki-67 LI) potentially associated with survival were entered into univariate and multivariate analyses using a Cox proportional hazards model. Variables that showed a significant and independent association with survival were Ki-67 LI (P < 0.002), whether total surgical resection had been achieved according to operation records (P < 0.03), and whether no adjuvant therapy had been given (P < 0.01). Age, sex, and the presence of necrosis or microvascular proliferation did not correlate with survival. In our defined population of patients with ependymomas, Ki-67 LI is a strong prognostic indicator. We recommend that Ki-67 LI is used in the histological evaluation of childhood posterior fossa ependymomas during trials of novel adjunctive therapies.

Ependymomas: MIB-1 proliferation index and survival

The biologic behavior of ependymomas is highly variable, and its correlation with histologic features is at best imprecise. This retrospective study attempted to correlate the malignant histologic characteristics of ependymomas with MIB-1 proliferation index and survival. Biopsy and resection specimens taken from 34 patients who received treatment 1972 to 1996 were histologically examined. The patients' ages range was 1 to 59 years. The histologic specimens were assessed for anaplastic features (necrosis, mitosis, vascular proliferation, cellular pleomorphism, and overlapping of nuclei) and an MIB-1 (Ki-67 antigen) proliferation index was also determined. The overall median MIB-1 proliferation index was 7.8% (range 0.1 - 62.5%). An MIB-1 of 20% was significant for a decrease in survival (RR = 5.7) (p = 0.0013). The median MIB-1 for patients < 20 years old was 20.6% with range (0.1, 43%), while that for patients > 20 years was 5.1% (range 0.2, 9.4%) (KW p = 0.055). Three of 5 histological features evaluated were significantly associated with outcome: > 5 mitotic figures per high-power field, necrosis, and vascular proliferation, but not nuclear overlap or pleomorphism. All pathologic factors except pleomorphism were significantly related to the MIB-1 proliferation index. In brief, our data support the association of poor prognoses in ependymomas with young age, the presence of three to four anaplastic histologic features, and an MIB-1 proliferation index > 20%.

Intracranial ependymomas in children: a critical review of prognostic factors and a plea for cooperation

BACKGROUND

Current controversies in pediatric intracranial ependymoma include histologic categorization and management. Most of our knowledge of this disease comes from single-institution reports.

METHODS

A literature search was done, covering the period 1976-1996. The aim of this review is to analyze the prognostic factors reported in the literature over the last 20 years.

RESULTS

Forty-five series were reviewed, including more than 1,400 children. The largest series reported on 92 patients, and the accrual rate ranged from 0.32-12 patients per year. None of the prognostic factors reported achieved a consensus throughout the different series. Histology remains a major issue, and the range in the incidence of anaplastic ependymo mas (7-89%) highlights the difficulty in agreeing on a histological grading system. The role of surgery on the outcome seems to be determinant. Recent series based on homogeneous imaging-documented extents of resection strongly support the benefit of postoperative radiotherapy. The lack of a proven, effective chemotherapy regimen precludes its use except in prospective pilot studies.

CONCLUSIONS

Limited information is available from single-institution reports in ependymoma. Only large national or international studies can provide enough information to allow a multivariate analysis of the prognostic factors, and thus lead to new therapeutic proposals.

Survival and prognostic factors following radiation therapy and chemotherapy for ependymomas in children: a report of the Children's Cancer Group

OBJECT

Ependymomas in children continue to generate controversy regarding their histological diagnosis and grading. optimal management, and possible prognostic factors. To increase our knowledge of these tumors the authors addressed these issues in a cohort of children with prospectively staged ependymomas treated with radiotherapy and chemotherapy.

METHODS

Children between the ages of 2 and 17.3 years harboring an intracranial ependymoma confirmed by a central review of the tumor's pathological characteristics were treated according to Children's Cancer Group Protocol 921 from 1986 to 1992. Treatment following surgery and postoperative tumor staging (including brain computerized tomography or magnetic resonance [MR] imaging, spinal MR imaging or myelography, and cerebrospinal fluid cytological investigation) included craniospinal irradiation with a local boost to the primary tumor and patient randomization to receive adjuvant chemotherapy with either 1) CCNU, vincristine, and prednisone, or 2) the eight-drugs-in-1-day regimen. Centralized review of the tumor pathological characteristics revealed 20 ependymomas and 12 anaplastic ependymomas in the 32 children included in the study. Diagnoses made at the individual institutions included anaplastic (malignant) ependymoma (15 patients), ependymoma (four patients), ependymoblastoma (nine patients), ependymoastrocytoma (one patient), and primitive neuroectodermal tumor (three patients), which were discordant with the centralized review diagnosis in 22 of 32 cases. Only three of the 32 patients had metastatic disease (two with M and one with M3 stages). At surgery, 47% of tumors were estimated to be totally resected. Among the 14 of 17 patients who suffered a relapse and were evaluated for site of relapse, 10 (71%) had an isolated local relapse, three (21%) had concurrent local and metastatic relapse, and only one (7%) had an isolated metastatic relapse. Kaplan-Meier estimates of 5-year progression-free survival (PFS) and overall survival rates were 50 +/- 10% and 64 +/- 9%, respectively.

CONCLUSIONS

Predictors of PFS duration included an estimate of the extent of resection made at surgery (total compared with less than total, p = 0.0001) and the amount of residual tumor on postoperative imaging as verified by centralized radiological review (< or = 1.5 cm2 compared with > 1.5 cm2, p < 0.0001). No other factors, including centrally reviewed tumor histopathological type, location, metastasis and tumor (M and T) stages, patient age, race, gender, or chemotherapy treatment regimen significantly correlated with PFS duration. The pattern of predominantly local relapse and the important influence of residual tumor or the extent of resection on PFS duration confirms a prevailing impression that local disease control is the major factor in the prediction of outcome of ependymoma. Survival rates were comparable with those reported by other investigators who have treated patients with similar doses of radiation and no chemotherapy.

Survival following intensive chemotherapy with bone marrow reconstitution for children with recurrent intracranial ependymoma--a report of the Children's Cancer Group

Recurrent intracranial ependymoma is rarely cured by surgery, radiotherapy, and chemotherapy in conventional doses. This study was designed to determine the toxicity, radiographic response rate and outcome following intensive chemotherapy with ThioTEPA, etoposide, carboplatinum and autologous bone marrow rescue (ABMR) for young children with recurrent central nervous system ependymoma. ThioTEPA 300 mg/m2/day (total 900 mg/m2) and etoposide 250 to 500 mg/m2/day (total 750 to 1500 mg/m2) were administered for three consecutive days with or without the addition of carboplatinum 500 mg/m2/day (total 1500 mg/m2) for an additional three consecutive days, and autologous bone marrow was reinfused 72 hours following chemotherapy. Eligibility criteria required adequate renal, hepatic and pulmonary function, and no tumor infiltration of bone marrow. Fifteen children with recurrent intracranial ependymoma, aged 5 months to 12 years (median 22 months), were treated. Five patients died of treatment related toxicities within 62 days of marrow reinfusion. Eight have expired from progressive disease a median of six months post-ABMR, and one has died from unrelated causes. One child remains alive 25 months post-ABMR, following further disease recurrence. No partial or complete responses were observed. This regimen of high-dose ThioTEPA and etoposide with or without additional carboplatinum with ABMR is not an effective strategy for retrieving heavily pre-treated children with recurrent ependymoma.

Postoperative radiotherapy of spinal and intracranial ependymomas: analysis of prognostic factors

PURPOSE

Postoperative radiation therapy adds significantly to disease control and survival of patients with ependymoma. However, much controversy exists about the radiation treatment policy. We report the long-term results of a cohort of 56 patients with primary intracranial and spinal ependymomas. Special effort has been taken to define prognostic indicators as a basis for future treatment strategies.

PATIENTS AND METHODS

Between November 1963 and May 1995, 56 patients with histological proven ependymoma were referred to our clinic for further treatment following surgery. Thirty patients had a high grading tumor and 26 had low grade tumors. Seventeen patients had supratentorial tumors and 24 had infratentorial tumors. Fifteen patients suffered from localized spinal tumors.

RESULTS

The mean survival time for all patients was 77 months. Five- and 10-year survival probabilities were 60 and 51%, respectively. The mean progression free survival (PFS) probability for all patients was 67 months with corresponding 5- and 10-year PFS probabilities of 53 and 39%, respectively. On univariate analysis initial performance status, age and tumor grade were significant for survival probability. Concerning PFS radiation dose was significant with improved survival with doses > 45 Gy. On multivariate analysis, tumor grade and initial performance status proved to be the only independent prognostic factors.

CONCLUSIONS

Tumor grade, age, initial performance status and radiation dose are significant factors for the clinical course of patients and have to be taken into account for the urgently needed prospective trials.

February 1997--9 year old girl with hydrocephalus

A nine year old girl presented with nausea vomiting and hydrocephalus. Imaging studies demonstrated a large right thalamic mass with areas of cystic change or necrosis. Sections of resected material showed perivascular pseudorosettes, necrosis, endothelial proliferation, numerous mitoses, densely cellular areas and numerous foci with a clear-cell morphology. This case is used to illustrate the features of anaplastic ependymomas and to discuss the relationship of the histologic features to prognosis.

Improving outcome of malignant brain tumours in very young children: a population-based study in Finland during 1975-93

Sixty-four children with malignant brain tumours diagnosed at less than 3 years of age were reported to the Finnish Cancer Registry from 1975 to 1993. The survival rate has improved significantly: the 5-year survival rate was 26% for all children, 13% for children diagnosed during 1975-85 (n = 30) and 40% for those diagnosed during 1986-93 (n = 34). Of the surviving children in 1986-93, 43% were categorized in Bloom's group I or II and could lead active lives without major disabilities. The remaining children had severe neurologic late complications, such as hemiplegia, intractable seizures, and mental retardation.

Anaplastic ependymoma: treatment of pediatric patients with or without craniospinal radiation therapy

The authors conducted a retrospective review of the clinical and treatment characteristics and outcomes in 28 pediatric patients with anaplastic ependymoma treated with radiation therapy since the advent of computerized tomography (CT) (1978-1994). Twelve patients received craniospinal irradiation followed by a boost to the primary site, two received whole-brain radiation therapy followed by a boost to the primary site, and the remaining 14 were treated with focal radiation therapy. The mean dose to the primary site was 5486 cGy. With a median follow-up period of 86 months for the 14 surviving patients (range 31-201 months), the median disease-free survival, measured from the date of diagnosis to the time of recurrence after radiation therapy, was 40 months. The median disease-free survival measured from the start of radiation therapy was 32 months. The median overall survival rate has not been reached and the actuarial estimates of overall survival rates at 5 and 10 years were 56% and 38%, respectively. According to univariate analysis, the disease-free survival rate was significantly improved (p < 0.01) in patients who underwent a gross-total resection at diagnosis. Overall survival rates were negatively influenced by treatment with craniospinal and whole-brain irradiation. As calculated by multivariate analysis, increasing dosage to the primary site (p < 0.05), infratentorial location (p < 0.01), and gross-total resections (p < 0.02) resulted in the longest disease-free survival times. All 19 patients in whom treatment failed after radiation therapy suffered a recurrence at the primary site. In addition, one of these patients experienced subarachnoid dissemination. Radiation treatment recommendations for patients with ependymoma have been based on the tumor's location, perceived risk for dissemination, and malignant propensity. The significance of anaplastic histological classification is controversial. Differences in the disease-free and overall survival rates have been demonstrated between ependymomas and anaplastic ependymomas treated in the pre-CT era. The results of this study show that there is no benefit from craniospinal irradiation in this group of patients.

The molecular biology of ependymomas

Intracranial ependymomas are the third most common primary brain tumor in the pediatric population. Although an anaplastic variant is recognized, numerous studies examining the prognostic implications of histological features, such as necrosis, endothelial proliferation and mitoses, have yielded contradictory results. In order to improve outcome prediction in affected patients and to refine therapeutic decision-making, there is a strong need for identifying relevant biological correlates of tumor behavior. The molecular biology of tumors is a rapidly expanding field and includes investigations into cytogenetics, oncogenes, growth factors, growth factor receptors, hormonal receptors, proliferation markers, apoptosis, cell cycle genes and cell adhesion molecules, as well as factors potentially related to therapeutic resistance, such as the multidrug resistance gene. The molecular biology of astrocytic tumors in adults has been the subject of many studies; however, relatively few studies have been focused on ependymomas. Herein we review potential oncological markers in ependymomas that have been identified to date and highlight the limitations of our current knowledge as a basis for defining areas for future investigation.

Spinal ependymomas--the value of postoperative radiotherapy for residual disease control

Spinal ependymomas are rare intramedullary tumours, usually with a benign biological nature. They have, however, a known potential for recurrence and metastatic spread through the CSF pathways. Traditionally, radiotherapy has been employed as an adjuvant to surgery. Recently, however, this view has been increasingly questioned. Thirty-eight adult patients operated in the West Midlands between 1956 and 1994 were reviewed. Mean age at presentation was 37.8 years. Of all tumours 45% (17) were situated in the conus/cauda equina region, 26% (10) in the thoracic and 29% (11) in the cervical region. All patients underwent surgery as primary treatment. Postoperative mortality was 2.6% (one patient). Complete macroscopic excision of their tumours was performed in 14 patients; of these three received postoperative radiotherapy. Subtotal excision was performed in 18 patients, seven receiving adjuvant radiotherapy. Decompressive laminectomy and biopsy was performed in five patients with either no radiotherapy in one, radiotherapy in three or radiotherapy and chemotherapy in one. The overall survival rate was 87% at 5 years and 73% at 10 years for the whole series. In patients treated after the 1970s, the cumulative 10-year survival was 95%. Patients over the age of 40 years at diagnosis had a 10-year survival of 61% compared to 78% of those under the age of 40. Intramedullary tumours had a worse outcome with 68% survival at 10 years, compared to 89% of tumours at the cauda equina. Total excision carried 86% survival, subtotal excision 80% and biopsy only 25% at 10 years. In those patients treated by administration of postoperative radiotherapy the 10-year survival was 48%, compared to 96% in those in whom radiotherapy was not given postoperatively. Analysis of the recurrence and survival rates demonstrated that radiotherapy did not confer any significant protection against recurrence or disease progression. Whilst complete excision offers the maximal potential for cure, an expectant policy with possible repeat surgery may be appropriate when total excision is not achieved. The main conclusion to be drawn is that a randomized controlled trial of the value of adjuvant radiotherapy is greatly needed.

Disseminated ependymomas of the central nervous system

Ependymomas are rare central nervous system (CNS) neoplasms that occasionally disseminate along the neuraxis or to extraneural sites. Definitive criteria predictive of dissemination have yet to be determined. One hundred forty patients with CNS ependymoma (88 primary spinal and 52 primary intracranial tumors) were surgically treated by the senior author (F.J.E.) between 1986 and 1994. Sixteen patients (11.4%) demonstrated tumor dissemination. The disseminated group consisted of 11 (12.5%) of 88 primary spinal and five (9.6%) of 52 primary intracranial ependymomas. The authors retrospectively reviewed the patients with CNS ependymoma and have identified several characteristics associated with dissemination from the primary tumor site. The mean time from diagnosis to dissemination was 6.8 years. The patients with disseminated disease were younger (16.8 vs. 28.3 years old, p = 0.02), had fewer gross-total resections (29% vs. 68%, p = 0.015), and had tumors with higher proliferative indices (MIB-1 staining, 13.14% vs. 2.06%, p = 0.02). High-grade tumors had a mean proliferation index of 21%, versus 2.4% and 1.6% for myxopapillary and low-grade tumors, respectively (p = 0.0003). In contrast to previous studies, tumor histology was the most significant variable for time to dissemination as determined by multivariate analysis (p = 0.008). Myxopapillary and high-grade tumors were 3.6 and 5.6 times more likely to have a shorter time to dissemination than low-grade tumors. In addition, dissemination is associated with a worse prognosis. At follow-up review, 31% of patients with disseminated disease had died compared to 7% of patients without dissemination (p = 0.04). It is concluded that younger patients with subtotal resections, myxopapillary or high-grade histology, and tumors with high proliferative indices are at substantial risk for the development of disseminated disease during their clinical course.

Intracranial ependymomas of childhood. Lack of correlation of histopathology and clinical outcome

The histopathology of 66 children with the diagnosis of ependymoma who were operated on at our institution between 1954 and 1994 were reviewed. We performed an initial analysis using the entire study cohort to determine which histopathological features associated with each other in a statistically significant fashion in an attempt to identify combinations of features that together might be useful in predicting outcome. A detailed outcome analysis was then performed on the 37 most recent cases who survived the postoperative period, in whom pre- and post-imaging studies as well as long term follow-up were obtained, in order to identify the histopathological features and combinations of features that were predictive of overall and progression-free survival. Five- and ten-year progression-free survivals were 45.1% and 36.1%, respectively. Overall survivals were 57.1% and 45.0%, respectively. Of the eight individual histopathological features, only the presence of necrosis was found to correlate with a less favorable overall and progression-free survival (PFS) (p = 0.06 and 0.03, respectively). In addition, the combination of necrosis with vascular proliferation or nuclear pleomorphism was associated with a worse PFS (p = 0.01 and 0.02, respectively). However, when other clinical predictive factors were included in a multivariate regression analysis, none of the histological features or combinations of features were independently associated with outcome. In addition, no relationship was found between the pattern of rosettes (true rosette, pseudorosette, or perivascular pseudorosette) and clinical outcome. In conclusion, although this study found an association between certain histopathological features and clinical outcome in children with ependymomas, these relationships did not reach statistical significance on multivariate analysis and, thus, do not provide sufficient evidence for modifying therapy based on histopathology alone.

Infrequency of p53 gene mutations in ependymomas

Ependymomas, which comprise 5% of central nervous system tumors, have not been extensively characterized genetically. The p53 tumor suppressor gene is frequently mutated in human cancer, and is important in the pathogenesis of other central nervous system (CNS) tumors. Chromosomal DNA corresponding to the p53 tumor suppressor gene was amplified by the polymerase chain reaction (PCR) from 31 archival ependymoma specimens. DNA was screened for the presence of p53 mutations by single strand conformational polymorphism (SSCP) analysis; samples with altered mobility were further tested for the presence of mutation by direct DNA sequence analysis. Of the 31 ependymomas tested, one contained a detectable DNA sequence change in the p53 gene. Sequencing revealed a silent mutation in exon 6, at codon 213, which represents a known p53 sequence polymorphism. These finding suggest that in contrast to many other human cancers, p53 mutation is not important in the pathogenesis or progression of ependymomas.

Chemotherapy with the "8 in 1" protocol for malignant brain tumors in children: a population-based study in Finland

We evaluated the outcome of 68 children with malignant brain tumors treated with the "8 in 1" chemotherapy protocol in Finland from 1986 to 1993, comparing 5-year survival rates with those for a historical control group (from 1975 to 1985). For all malignant brain tumors, overall survival was 43% (vs 28% in the control group; P <0.05), and progression-free survival (PFS) was 43% (vs 23%; P <0.05). For medulloblastoma and primitive neuroectodermal tumor, survival was 63% (vs 35%; P <0.05), and the corresponding PFS was 59% (vs 35%; P = 0.15). For high-grade glioma, both the survival rate and the PFS were 27% (vs 17%; P = NS). Thus the outcome was significantly better for our "8 in 1" -treated patients than for the historical controls, especially among the children with primitive neuroectodermal tumor and medulloblastoma. In contrast, those with high-grade gliomas and brain stem tumors seem to have received little benefit; different, more effective treatments are needed for these patients.

A grading study of gliomas using computer aided malignancy classification and histologic morphometry

Forty three cases of astrocytic tumors and mixed gliomas were studied with the aim of evaluating the reproducibility of the Kernohan grading system vis a vis (a) grading using computer-aided malignancy classifier TESTAST 268 and (b) grading by quantitative morphometric evaluation of the various histological parameters of TESTAST 268. These patients were then followed up for variable periods with a maximum of forty months. High inter and intra-observer variability were observed in the Kernohan grading system. TESTAST 268 was found to be simpler, rapid and more reproducible. However, one drawback observed of this system was that it did not completely eliminate inter-observer variability because there was still some subjectivity in assignment of the categorical values against the histological features. Morphometric evaluation of the semi-quantitative assignment values of the 4 histological variables in the TESTAST 268 classifier using Zeiss Morphomat-30 revealed a statistically significant difference between the clusters of the measured quantitative values. A repeat grading using TESTAST 268 and categorical assignment values of histological features derived from the absolute values obtained by morphometry resulted in complete elimination of inter-observer variability. Thus, this study highlights the importance of objectivisation using TESTAST 268 and histologic morphometry in the grading of gliomas. However, since this is a preliminary study on a small number of cases, no cut off values of these measurements have been proposed.

Intracranial ependymomas of childhood: long-term outcome and prognostic factors

A detailed outcome analysis was performed on 40 children with intracranial ependymomas treated at our institution between 1975 and 1993 to identify those factors that were predictive of overall and progression-free survival. Three patients (7.5%) who were treated in the first 5 years of the study died within 3 months of surgery and were excluded from further outcome assessments. Eight (22%) of the 37 patients who survived the perioperative period had evidence of leptomeningeal dissemination at presentation, on the basis of either imaging (three children) and/or cytological (six children) results. The 5- and 10-year progression-free survival rates among these 37 patients were 45.1 and 36.1%, respectively; overall survival rates were 57.1 and 45.0%, respectively. The site of progression was local in 17 of 19 patients with progressive disease. Three factors were found to have a significant association (P < or = 0.05) with the outcome on both univariate and multivariate analyses: 1) the extent of the resection, 2) the age of the patient at diagnosis, and 3) the duration of the symptoms before diagnosis. The 5-year progression-free and overall survivals were 8.9 and 22%, respectively, among patients who had evidence of residual disease on postoperative imaging studies, compared with 68 and 80% rates among patients with no apparent residual disease (P = 0.0001 and P < 0.0001, respectively). Patients younger than 3 years fared significantly worse than older children (5-year progression-free and overall survival rates of 12 and 22%, respectively, in the younger children versus 60 and 75% in older children (P = 0.003 and P = 0.01, respectively). In addition, patients with a duration of symptoms before diagnosis of < 1 month had a worse outcome than those with a more protracted course (5-year progression-free and overall survival rates of 33 and 33%, respectively, versus rates of 53 and 64%, respectively (P = 0.02 for both). Neither the finding of evidence for dissemination at presentation nor the detection of anaplastic histological features (e.g., dense cellularity or high numbers of mitoses) were associated with a significantly worse outcome in this series. The combination of variables that had the strongest association with both favorable and unfavorable outcomes was the combination of the age of the patient and the resection extent. Only 2 of 17 patients older than 3 years with gross total resections have died, whereas 13 of 20 children who were either younger than 3 years or had radiologically incomplete resections have died (P < 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

Anaplastic ependymomas: clinical features and tumour suppressor gene p53 analysis

We analyzed seven cases of anaplastic ependymoma, focusing on neuro-imaging, histopathology, and mutations of the tumour suppressor gene p53. Five of the seven tumours were supratentorial. All had both cystic and solid components, with fragment calcifications detectable on CT scan. The solid parts of the tumours were imaged as heterogenous hypo- or iso-intense areas with moderate enhancement on T1-weighted magnetic resonance images. Vascularity was not prominent on angiograms except for one case. Histologically, in addition to the WHO criteria, loss of typical cellular architecture, endothelial proliferation, and necrosis were commonly found. A mutation in Exon 5 of the tumour suppressor gene p53 was detected in one anaplastic ependymoma out of five tumours (two benign and three anaplastic ependymomas) examined by PCR-SSPC analysis of genomic DNA followed by direct sequencing. Anaplastic ependymoma typically presents as a calcified cystic tumour in the supratentorial parenchyma or transependyma. Mutations of p53 deserve further investigation to examine their possible role in the oncogenesis and malignant transformation of ependymoma.

Retrolumbar subcutaneous ependymoma and giant bathing-trunk nevocellular nevus

BACKGROUND

Subcutaneous ependymomas have been reported rarely in dermatologic reviews and, apparently, were never associated with other cutaneous malformations.

METHODS

A 60-year-old woman with a retrolumbar subcutaneous ependymoma and a giant bathing-trunk nevocellular nevus submitted to thorough dermatologic and neurologic investigation. The surgical material was extensively analyzed with light and electron microscope. The literature was reviewed.

RESULTS

The tumor fits exactly the classical prerequisites of the clinical and pathologic diagnosis. In contrast with the literature, it developed at 53 years, apparently after a trauma, within a congenital giant nevocellular nevus, at the retrolumbar level; it proved unrelated to any spinal cord alteration and so far appeared quite benign.

CONCLUSIONS

The observation of a retrolumbar subcutaneous ependymoma is reported with detail; this tumor exceptionally recognized by dermatologists must be included in the differential diagnosis of lumps arising in the retrolumbar-retrosacral area. The most peculiar feature was its development within a giant bathing-trunk nevocellular nevus; such a fascinating association of two neurectodermal defects, as far as known, is presented for the first time.

Ependymomas in children: histologic and DNA-flow cytometric study

Ependymoma, a common neoplasm in the central nervous system of children, expresses great variability of morphological appearances. Correlation with clinical behavior has been controversial in previous studies. In order to explore the potential value of DNA-flow cytometric analysis in predicting the clinical course of ependymomas in children, we studied 22 patients with this tumor, selected from two large pediatric institutions. In addition, a number of histologic features were reviewed, such as necrosis, mitoses, endothelial proliferation, cellularity, and pleomorphism. DNA analyses of paraffin-embedded tissue from these tumors showed 9 of 17 (53%) with DNA indexes less than 1.16 and 8 of 17 (47%) with DNA indexes above 1.16. Ten of 17 (59%) patients died, 2 (12%) were lost for follow-up, and 5 (29%) are alive. No statistical correlation was found between DNA index, outcome, and histology. In spite of the small sample size, our findings appear to support the general impression that ependymomas are morphologically highly variable tumors of potential aggressiveness without valuable prognostic histologic markers.

Ultrastructure of ependymoma

Twenty-six ependymomas were studied by light and electron microscopy. By electron microscopy, the acellular zones around small vessels in light microscopic sections were seen to be composed of large numbers of closely packed, filament-rich, cytoplasmic processes ringing small vessels. Lumina were consistently present but many of them were too small to be seen by light microscopy. The lumina contained slender, curving microvilli and variable numbers of cilia. Their bordering cells were connected by unusually long tight junctions. Electron microscopy can be useful to establish or confirm a diagnosis of ependymoma when the light microscopic appearance is atypical, or when the tumor arises in an unusual location. The clinical data on the 26 cases has been reviewed; follow-up information was available on 23 patients.