Cytogenetic studies of human brain tumors and their clinical significance. II. Meningioma.

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.