Pleomorphic xanthoastrocytoma: New ultrastructural observations

A 58 year old woman presented with a right frontal lobe cystic mass diagnosed as pleomorphic xanthoastrocytoma (PXA), in which a reticulin fiber network was not evident but prominent vasculature was noted (angiomatous variant). The patient had a 36 year history of epileptic seizure which had been relatively well controlled with anticonvulsants. An ultrastructural study revealed that the neoplastic astrocytes occasionally contained filamentous inclusions identical to Hirano bodies in their cytoplasm and that, at the periphery of the tumor, pre‐existing axon terminals and synaptic junctions were found in close proximity to neoplastic astrocytes. The former may represent a degenerative process in the constituent neoplastic astrocytes and the latter appears to be of interest when considering the epileptogenic lesions associated with this type of benign tumor.