A 34-year-old woman presented with a history of persisting headache for years, and a newly developed dizziness, left facial palsy and right hemiparesis two days prior to this admission. Initial computed tomographic angiography of the head demonstrated an area of increased density in the left middle and posterior fossae. Multiple aneurysmally dilated venous ectasias with contrast enhancement at the left pre-pontine cistern causing a massive mass effect to the brainstem were also noted, suggesting a huge vascular abnormality. Digital subtraction angiography revealed an abnormal vascular lesion surrounding the brainstem, which indicated a left direct carotid-cavernous fistula with posterior drainage. As her consciousness deteriorated the next day, a follow-up computed tomography scan was done which revealed a pontine hemorrhage. Subsequently, endovascular closure of the fistula with sacrifice of the left ICA was performed, which successfully eliminated the imaging abnormalities.
Keywords: brainstem hemorrhage; carotid-cavernous fistula; venous pouch.