Evolution to malignancy in a recurrent meningioma: morphological and cytogenetic findings

The original tumor and 4 relapses of a recurrent meningioma were studied. We analyzed and compared these recurrences by histopathology, PCNA labelling index (PCNA-LI), nuclear count, and cytogenetical findings. The most important changes in the evolution to aggressivity were: recurrences at progressively shorter intervals, increases in the PCNA-LI, and micronecrosis; histological changes such as sheeting and increase of the extracellular matrix and a gradual transformation to a clonally complex karyotype.

Meningiomas: karyotypes and histological patterns

The cytogenetic findings, based on G-banding, in six meningiomas are reported. Normal karyotypes were found in three cases and monosomy of chromosome 22 in the remaining three. In one of these three cases, a malignant meningioma, several chromosomes were lost, gonosome Y included. The possible significance of the association of chromosome alterations in meningiomas with the histology of the tumor and its biological aggressivity is discussed.