To contribute to a better understanding of the prognostic differences between atypical and malignant meningiomas as defined by the World Health Organization (WHO) and the influence of the grade of initial surgical excision on postoperative course, 42 cases of atypical and 29 of malignant meningioma were studied, along with long-term follow up. The two groups were compared with respect to long-term survival, recurrence-free survival, and median time to recurrence. The prognostic significance of the Simpson grade of surgical resection and tumor location was also considered. Survival at 5 and 10 years was recorded in 95% and 79%, respectively, of patients with atypical meningioma and in 64.3% and 34.5% of patients with malignant meningioma (p = 0.001). Recurrence-free survival and median time to recurrence were also significantly longer in patients with atypical than in those with malignant meningiomas: 11.9 versus 2 years (p = 0.001) and 5 versus 2 years (p < 0.0041), respectively. Six (26%) of the 23 recurring atypical meningiomas became malignant. Simpson Grade I resection and location in the cerebral convexity, which were closely related, were found to be associated with a significantly better clinical course in the entire series (p < or = 0.0016). Patients with atypical meningiomas fared better than those with malignant meningiomas after incomplete surgical excision (Simpson Grades II-III), but the difference was not statistically significant. Multivariate analysis using the Cox model indicated that radical extirpation (Simpson Grade I vs. II-III) and histological findings (atypical meningioma vs. malignant meningioma) were significantly related to prolonged survival (p < 0.0003 and p < 0.0388, respectively). In conclusion, the current study shows that for most patients with atypical meningioma the prognosis was less severe than for those with malignant meningioma, but the risk of a downhill course resulting from malignancy after incomplete resection and recurrence was not negligible (26%). In addition, the WHO classification was found to be inadequate for a minority of the atypical meningioma cases, which currently have the same unfavorable course as cases of malignant meningioma. The results also indicate that objective Simpson Grade I extirpation of convexity meningiomas can be successful despite histological findings of malignancy.

The prognostic value of a series of histologic signs and clinical features was studied in a series of 298 ependymomas, collected from different institutions. The distribution of tumor sites varied in relation to patient age, with infratentorial cases prevailing under 4 years. Life table univariate analysis demonstrated as highly significant prognostic factors: (1) the number of mitoses; (2) endothelial hyperplasia; (3) necrosis; (4) intracranial site; (5) age less than 4 years. Multivariate analysis by tumor site revealed mitoses cell density, age greater than 16 years in supratentorial cases, and subependymoma in infratentorial cases to be prognostically important. Comparison of the anaplastic variant with the other tumor types in intracranial cases did not show a significant difference in survival even though the median survival time of anaplastic cases was shorter. The main conclusion is that the histological criteria employed to diagnose anaplasia in ependymomas. The number of mitoses is a very important prognostic factor in supratentorial cases, whereas endothelial proliferations and necroses are much less important as prognostic factors than in gliomas.

In view of the widely recognized correlation between extent of surgical resection and length of survival of children with intracranial ependymoma and the statement that total resection is more likely to be achieved in supratentorial than infratentorial primaries, we decided to review our experience with supratentorial ependymomas and the pertinent literature to verify the importance of surgery in treating this subgroup of pediatric ependymal neoplasms. Of 23 patients operated on, 12 are still alive without evidence of disease 72-357 months after surgery (mean 227, median 237 months). One girl treated by surgery alone was lost to follow-up after 234 months when she, and 7 other patients in the series, had already passed the end of the period of risk for recurrence according to Collins' law. Six surviving patients (2 with subependymoma and 4 with ependymoma) were treated by surgery alone and only 1, the oldest in the series, had to undergo a second operation for recurrence after 10 years. The idea of treating intracranial ependymoma by surgery alone was favored by eminent neurosurgeons in the past and has recently received renewed attention. This was in part the consequence of recognizing that unlike diffuse astrocytoma, in which neoplastic cells can be found up to several centimeters away from the apparent tumor borders, ependymoma has more or less well-defined margins and grows mainly by expansion. Early experience with the policy of electively deferring adjuvant therapy after radiologically controlled total resection of ependymoma seems encouraging, although postoperative MRI does not yet indicate absolute certainty. Close surveillance is recommended. The majority of ependymomas so far treated by surgery alone, with relatively good success, have been supratentorial. In conclusion, on the basis of our experience and a review of the literature we favor a change in attitude to the management of intracranial ependymomas, especially of the cerebrum, with radiologically controlled radical surgery alone followed by close surveillance with periodic MR imaging until the child passes the period of risk for recurrence according to Collins' law as the initial option. In children less than 3 years old the period of surveillance should be doubled. In case of recurrence, reoperation should be considered first, particularly for supratentorial primaries. Radiotherapy continues to be a major option in malignant ependymoma and unresectable primary or recurrent benign ependymoma.

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To contribute to a better understanding of the prognostic differences between atypical and malignant meningiomas as defined by the World Health Organization (WHO) and the influence of the grade of initial surgical excision on postoperative course, 42 cases of atypical and 29 of malignant meningioma were studied, along with long-term follow up. The two groups were compared with respect to long-term survival, recurrence-free survival, and median time to recurrence. The prognostic significance of the Simpson grade of surgical resection and tumor location was also considered. Survival at 5 and 10 years was recorded in 95% and 79%, respectively, of patients with atypical meningioma and in 64.3% and 34.5% of patients with malignant meningioma (p = 0.001). Recurrence-free survival and median time to recurrence were also significantly longer in patients with atypical than in those with malignant meningiomas: 11.9 versus 2 years (p = 0.001) and 5 versus 2 years (p < 0.0041), respectively. Six (26%) of the 23 recurring atypical meningiomas became malignant. Simpson Grade I resection and location in the cerebral convexity, which were closely related, were found to be associated with a significantly better clinical course in the entire series (p ¾ 0.0016). Patients with atypical meningiomas fared better than those with malignant meningiomas after incomplete surgical excision (Simpson Grades II-III), but the difference was not statistically significant. Multivariate analysis using the Cox model indicated that radical extirpation (Simpson Grade I vs. II-III) and histological findings (atypical meningioma vs. malignant meningioma) were significantly related to prolonged survival (p < 0.0003 and p < 0.0388, respectively). In conclusion, the current study shows that for most patients with atypical meningioma the prognosis was less severe than for those with malignant meningioma, but the risk of a downhill course resulting from malignancy after incomplete resection and recurrence was not negligible (26%). In addition, the WHO classification was found to be inadequate for a minority of the atypical meningioma cases, which currently have the same unfavorable course as cases of malignant meningioma. The results also indicate that objective Simpson Grade I extirpation of convexity meningiomas can be successful despite histological findings of malignancy.