De novo formation of a large cavernoma associated with a congenital torcular dural arteriovenous fistula: case report.

The authors report a case of a developmentally normal child with a congenital complex torcular dural arteriovenous fistula (DAVF) who later, in his teenage years, developed several vermian cavernomas within a large cerebellar developmental venous anomaly (DVA). The patient had initially presented with an abnormally large head circumference but no neurological deficits. He underwent several partial embolization procedures in an attempt to decrease the blood supply of the fistula over the course of 8 years. Nine years following initial presentation, he presented with a fourth ventricular hemorrhage, due to development of a new vermian cavernoma adjacent to a previously known vermian DVA and suffered subsequent mild left-sided hemiataxia from which he later recovered. CT angiographic images demonstrated that the vermian DVA drained into the left transverse sinus, which also drained the torcular arteriovenous fistula. A routine follow-up MRI examination 10 years following initial presentation demonstrated interval development of several large cavernomas in the cerebellum, all within the DVA. The patient had no new symptoms at that time and was neurologically intact. This case report highlights the de novo development of multiple cavernous malformations potentially secondary to DAVF-induced venous congestion in a preexisting DVA.