RESUMO
Cytogenetic study of 45 meningiomas from 31 female and 14 male patients are reported. No chromosomal abnormalities were found in nine (20%). These were predominantly meningotheliomatous, and were from younger patients (average age, 46 years). Monosomy 22 was noted in only 20% and in 12 patients (27%) with other losses and rearrangements. Among the latter, 50% were either recurrent or recurrent and invasive, the majority were fibromatous and occurred in older patients. Nonrandom loss was observed of the Y and abnormalities of chromosomes #1, #7, and #14 and, to a lesser extent, chromosomes #18, #19, and #20. Meningiomas may begin with no chromosomal abnormalities, having meningotheliomatous histopathologic appearance, occur in younger patients, and are less aggressive. Karyotypic evolution following loss of a chromosome #22 continues with losses and rearrangements of other chromosomes with apparent nonrandom involvement of chromosomes #1, #7, #14 and Y. This karyotypic change is associated with aggressive tumor behavior and fibromatous morphology.