[A case of ruptured internal carotid artery aneurysm mimicking pituitary apoplexy]

A 48-year-old female presented with a sudden onset of headache and visual impairment. Nineteen years before, she had undergone a transsphenoidal surgery for a prolactin producing pituitary adenoma at our hospital without intraoperative arterial bleeding. On arrival, she exhibited dilated pupils and loss of bilateral visual acuity, but improved immediately after all examinations. MRI revealed a pituitary tumor with intratumoral hemorrhage, intraventricular hemorrhage and subdural hemorrhage. Cerebral angiography revealed a left intracavernous carotid artery aneurysm. Her medical history and radiological findings suggested the rupture of a de novo aneurysm causing a hemorrhage into a pituitary adenoma mimicking pituitary apoplexy. Endovascular occlusion of the aneurysm was performed by use of platinum coils. Because of rapid improvement of visual acuity, administration of terguride was chosen for shrinking the pituitary adenoma. If a pituitary adenoma is present, the possibility of a coincidental aneurysm should always be considered. This association should be kept in mind when evaluating any case of pituitary apoplexy.