Cytogenetic studies of 11 meningiomas and their clinical significance. II.

Cytogenetic analyses of 11 consecutive cases of meningiomas from 7 female and 4 male patients are reported. Chromosomal abnormalities were found in all cases. Only two of the cases showed cells with normal karyotype in addition to the abnormal stemline. Two of the cases displayed a more aggressive growth pattern than is usually seen in meningiomas. The first case was characterized by tumor invasion into the bone, a stemline with monosomy 22 and a hyperhaploid sideline. The second case was characterized by recurrency and a hypodiploid stemline. Extended clonal evolution was observed in one case.