Clinical Analysis of Atypical and Malignant Meningiomas: A study of 52 Cases

ABSTRACT

OBJECTIVE: Atypical and malignant meningiomas(AM, MM) are known to be rare and show aggressive behavior. Limited data are available concerning the clinical features, effectiveness of surgical removal and role of radiation therapy with AM, MM. The authors report our experience of AM, MM, with respect to clinical features. METHODS: Twenty-four cases of AM and 28 cases of MM, who were operated between 1988 and 1999 were retro-spectively studied review of medical records and radiological findings. These were compared with control group of 24 cases of menigiomas manifestating usual clinical course, which are selected arbitrarily among operative cases between Apr. 1999 and Dec. 1999. Mean follow-up periods were 26(1-91) months for AM and 23(1-62) for MM. Authors analyzed the prognostic factors for survival, and statistical analysis were accomplished by Kaplan-Meier method and log-rank test. RESULTS: Differences of clinical features between control groups and these atypical and malignant meningioma group were not significant. However, the location of MM was frequent in non-basal area(p<0.01). In AM, there were 4 patients of recurrence, and 3 patients of mortality. Among mortality cases, only one patient died of tumor progression, the other patients died of other causes. The survival at 2 year and 5 year in this group were 88% and 74% respectively, and in MM, 11 patients died due to tumor progression and 2 had spinal metastasis. The survival at 2 year and 5 year were 72% and 20%, respectively. For extent of resection, total removal(Simpson grade 1 or 2) was less often achieved in MM compared with AM(50% vs. 83%). Extent of resection of tumor and postoperative radiation therapy did not affect survival in both AM, MM. CONCLUSIONS: Clinical behavior of AM showed more benign than that of MM. Prognostic factor for survival is not related extent of resection of tumor and postoperative radiation therapy. However, further investigation with long-term follow-up and additional cases is mandatory.