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We retrospectively evaluated 90 meningiomas for bcl-2 expression, apoptosis counts (per 10 high-power fields [HPF]), MIB-1 labeling indices (LI), and mitosis counts (per 10 HPF). Characteristics were as follows: 37 low-grade (benign) meningiomas: mean apoptosis count, 1.2; MIB-1 LI, 1.0; mitosis count, 0.1; and bcl-2 positivity, 40%; 29 atypical meningiomas: apoptosis count, 3.3; MIB-1 LI, 5.5; mitosis count, 2.2; and bcl-2 positivity, 62%; 24 malignant meningiomas: apoptosis count, 6.5; MIB-1 LI, 12.0; mitosis count, 6.0; and bcl-2 positivity, 67%. By univariate analysis, MIB-1 LI, apoptosis and mitosis counts, and tumor grade were associated significantly with death due to tumor; by multivariate analysis, only mitosis count was independently associated with death due to tumor. We compared similar data for 27 patients with nonrecurrent tumors and 32 patients with recurrent meningiomas. Histologic sections from the initially resected tumor and from the most recent recurrence were reviewed. Only the apoptosis count was significantly higher by univariate analysis in the initial resection specimens from tumors that ultimately recurred vs nonrecurrent tumors. Expression of bcl-2, MIB-1 LI, and mitosis count did not correlate with recurrence. By multivariate analysis, only extent of surgical resection was associated significantly with tumor recurrence. Although bcl-2 immunostaining was not associated statistically with outcome, bcl-2 positivity was more common in atypical and malignant meningiomas than in low-grade tumors.

Mixed glioneuronal neoplasms are relatively uncommon tumors in the central nervous system. Recently, an unusual glioneuronal tumor arising in adults marked histologically by neuropil-like islands was described. We present a similar case arising in a 23-year-old woman who presented with headaches and seizures and on imaging studies was noted to have a frontal-temporal lobe mass. The patient underwent partial resection of the tumor, which histologically resembled anaplastic astrocytoma, and received a course of radiation therapy and chemotherapy. Increasing seizure frequency and expanding size on neuroimaging prompted a re-excision of the tumor. The second resection was marked by islands of tissue resembling gray matter with slightly atypical neuronal and glial cells situated in the white matter. These islands stained positively with synaptophysin and did not stain with glial fibrillary acid protein. Mild vascular proliferation and moderate nuclear pleomorphism also characterized the tumor. Areas of necrosis were not noted. A MIB-1 labeling index of 18.1% was noted. P53 immunoreactivity was observed in approximately 40% of tumor cell nuclei. This lesion is felt to represent a clinically aggressive glioneuronal neoplasm with an unusual and distinctive histologic phenotype. HUM PATHOL 31:1435-1438.