Pituitary enlargement in a carotid-cavernous fistula: An atypical imaging manifestation.

A carotid-cavernous fistula is a rare abnormal communication between carotid vasculature and the cavernous sinus. Development of a carotid-cavernous fistula often results from trauma, but may be spontaneous in the setting of predisposing risk factors. Suspicion for a spontaneous fistula is understandably low on routine non-contrast imaging. In this article, we present a case of a carotid-cavernous fistula initially presenting with the potentially underrecognized imaging manifestation of diffuse pituitary enlargement identified on a non-contrast CT, later revealed to be due to the presence of the fistula.