Anaplastic oligo-astrocytoma occurring after resection of a cerebral cavernous malformation; malignant transformation? Case report and review on etiology.

We report a 71-year-old woman who presented with a cerebral cavernous malformation in the right frontal lobe for which she underwent total resection. Three years later, she was admitted with seizures and neuroimaging revealed a partially calcified lesion in the area of the earlier cavernous malformation, consistent with a residual malformation. A few months later she presented with cognitive decline and neuroimaging now revealed a large mass lesion in the same area as the cavernous malformation, irregularly enhancing, spreading through the corpus callosum to the left frontal lobe. Histological examination showed an anaplastic oligo-astrocytoma. These findings suggest that cerebral cavernous malformations, or at least a subgroup, have the potential for oligodendrocytic and astrocytic transformation. Various hypotheses to explain the etiology of these rare cases are discussed.