Histopathological and cytogenetic findings in benign, atypical and anaplastic human meningiomas: a study of 60 tumors

Meningiomas may display benign (grade I), atypical (grade II) and anaplasti c (grade III) histopathological findings. The cytogenetic studies strongly suggest that secondary changes (beyond loss of chromosome 22) appear to be associated with more atypical features and with greater clinical aggressivi ty. We studied 60 tumors from 52 patients. Histopathological features such as nuclear pleomorphism, nucleolar prominence, mitosis, necrosis, cellular density, PCNA labeling index, and karyotype have been evaluated. The distri bution in histological grades was: 50% benign, 33% atypical and 17% anaplas tic meningiomas. Nuclear pleomorphism and nucleolar prominence showed a pro gressive increase in grades I, II and III. Multifocal micronecrosis was con sidered a criterion of malignancy. A significant correlation was observed b etween PCNA-LI, mitotic index and grades. Complex karyotypes increased prog ressively: benign (34% of cases), atypical (45% of cases) and anaplastic (7 0% of cases). The most common numerical alterations were losses of chromoso mes 10, 14, 18 and 22. The chromosomes most often involved in structural an omalies were: 1, 4, 7, 14 and 22. Telomeric associations were present in fo ur cases and double minutes in two cases. Prognostic criteria for these tum ors have been analyzed on the basis of these data.