Oligodendroglial proliferative abnormality associated with arteriovenous malformation: report of three cases with review of the literature.

A peculiar nonneoplastic oligodendroglial proliferative abnormality associated with cerebral arteriovenous malformations (AVMs) was present in three patients. Histological examination of biopsy material revealed dense oligodendroglial tissue reminiscent of oligodendroglioma in the white matter adjoining the AVMs. Careful consideration of clinical and pathological features suggested that the evidence was insufficient to qualify the lesion as truly neoplastic (oligodendroglioma); rather, a tissue collapse or a hamartomatous proliferation could be considered to be its cause. The literature contains 14 instances of various vascular malformations associated with primary brain tumors, 5 of which were diagnosed as oligodendrogliomas. It is possible, however, that some of the cases reported in the literature constitute oligodendroglial abnormality similar to that observed in our cases rather than genuine oligodendrogliomas. Attention is drawn to this interesting and prognostically important phenomenon.