Histogenesis of intracranial haemangiopericytoma and haemangioblastoma. An immunohistochemical study.

An immunohistochemical study was performed on three meningeal haemangiopericytomas and four cerebellar haemangioblastomas (paraffin embedded) in an attempt to elucidate the uncertain histogenesis of these tumours. The tumour cells of all meningeal haemangiopericytomas show no expression of alpha-smooth muscle actin and, thus, no immunohistochemical proof of their true pericytic nature can be obtained. The stromal cells of cerebellar haemangioblastomas show foci of positive staining for S-100 protein, neuron-specific enolase and synaptophysin, thereby clearly indicating their neuroectodermal origin. These results allow the conclusion that the present nomenclature of these tumours is at least arguable and probably incorrect.