The contribution of cytogenetics to the histogenesis of meningeal hemangiopericytoma.

Some controversy has existed regarding the nosology of meningeal hemangiopericytoma. In the WHO's classification of 1979 these tumours were included as a subgroup of meningiomas, but for some authors, they should not be classified as meningiomas. Cytogenetic studies on meningioma demonstrate monosomy or partial deletion of chromosome 22 in 60% of these tumors. There have been few cytogenetic studies about meningeal hemangiopericytoma. We present here the results of cytogenetic studies and fluorescence in situ hybridization in six cases of meningeal hemangiopericytoma. In these tumours we have never found monosomy 22, but all six cases were hyperdiploid. These cytogenetic data might provide additional evidence to differenciate the meningeal hemangiopericytoma from the meningioma.